52001PC0508

Proposal for a REGULATION OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL relating to fertilizers

(presented by the Commission)

TABLE OF CONTENTS

EXPLANATORY MEMORANDUM

1. General Comments

1.1. Policy

1.2. Directives concerned

1.3. Drafting Methodology and Structure

1.3.1. SLIM recommendations

1.3.2. Structure

1.4. Cadmium

1.4.1. The problem

1.4.2. Strategy

2. Specific Comments

REGULATION OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL

relating to fertilizers

ANNEX I - List of types of EC fertilizers

A. Inorganic straight primary nutrient fertilizers

A.1. Nitrogenous fertilizers

A.2. Phosphatic fertilizers

A.3. Potassic fertilizers

B. Inorganic compound primary nutrient fertilizers

B.1. NPK fertilizers

B.2. NP fertilizers

B.3. NK fertilizers

B.4. PK fertilizers

C. Inorganic fluid fertilizers

C.1. Straight fluid fertilizers

C.2. Compound fluid fertilizers

D. Inorganic secondary nutrient fertilizers

E. Inorganic micro-nutrient fertilizers

E.1. Fertilizers containing only one micro-nutrient

E.1.1. Boron...

E.1.2. Cobalt..

E.1.3. Copper.

E.1.4 Iron.....

E.1.5. Manganese

E.1.6. Molybdenum

E.1.7. Zinc.....

E.2. Minimum micro-nutrient content, percentage weight of fertilizer

E.3. List of authorised organic chelating and complexing agents for micro-nutrients

ANNEX II - Tolerances

1. Inorganic straight primary nutrient fertilizers - absolute value in percentage by mass expressed as N, P2O5, K2O, mgo, Cl

2. INORGANIC COMPOUND PRIMARY NUTRIENT FERTILIZERS

3. SECONDARY NUTRIENTS IN FERTILIZERS

4. MICRO-NUTRIENTS IN FERTILIZERS

ANNEX III - Technical provisions for Ammonium Nitrate Fertilizers of High Nitrogen Content

1. CHARACTERISTICS OF AND LIMITS FOR STRAIGHT AMMONIUM NITRATE FERTILIZERS OF HIGH NITROGEN CONTENT

2. DESCRIPTION OF THE TEST OF RESISTANCE TO DETONATION CONCERNING AMMONIUM NITRATE FERTILIZERS OF HIGH NITROGEN CONTENT

3. METHODS OF CHECKING COMPLIANCE WITH THE LIMITS SPECIFIED

IN ANNEXES III-1 and III-2

4. DETERMINATION OF RESISTANCE TO DETONATION

ANNEX IV - Methods of Sampling and Analysis

A. METHOD OF SAMPLING FOR THE CONTROL OF FERTILIZERS

1. PURPOSE AND SCOPE

2. SAMPLING OFFICERS

3. DEFINITIONS

4. APPARATUS

5. QUANTITATIVE REQUIREMENTS

6. INSTRUCTIONS FOR TAKING, PREPARING AND PACKAGING THE SAMPLES

7. PACKAGING OF FINAL SAMPLES

8. SAMPLING RECORD

9. DESTINATION OF SAMPLES

B. METHODS FOR THE ANALYSIS OF FERTILIZERS

GENERAL OBSERVATIONS

GENERAL PROVISIONS RELATING TO METHODS OF ANALYZING FERTILIZERS

Method 1 - PREPARATION OF THE SAMPLE FOR ANALYSIS

Methods 2 - NITROGEN

Method 2.1 - DETERMINATION OF AMMONIACAL NITROGEN

Methods 2.2 - DETERMINATION OF NITRIC AND AMMONIACAL NITROGEN

Method 2.2.1 - DETERMINATION OF NITRIC AND AMMONIACAL NITROGEN

ACCORDING TO ULSCH

Method 2.2.2 - DETERMINATION OF NITRIC AND AMMONIACAL NITROGEN ACCORDING TO ARND

Method 2.2.3 - DETERMINATION OF NITRIC AND AMMONIACAL NITROGEN ACCORDING TO DEVARDA

Method 2.3 - DETERMINATION OF TOTAL NITROGEN

Method 2.3.1 - DETERMINATION OF THE TOTAL NITROGEN IN CALCIUM CYANAMIDE NITRATE FREE

Method 2.3.2 - DETERMINATION OF TOTAL NITROGEN IN CALCIUM CYANAMIDE

CONTAINING NITRATES

Method 2.3.3 - DETERMINATION OF TOTAL NITROGEN IN UREA

Method 2.4 - DETERMINATION OF CYANAMIDE NITROGEN

Method 2.5 - SPECTROPHOTOMETRIC DETERMINATION OF BIURET IN UREA

Methods 2.6 - DETERMINATION OF DIFFERENT FORMS OF NITROGEN IN THE SAME

SAMPLE

Method 2.6.1 - DETERMINATION OF DIFFERENT FORMS OF NITROGEN IN THE SAME SAMPLE IN FERTILIZERS CONTAINING NITROGEN AS NITRIC, AMMONIACAL, UREA AND CYANAMIDE NITROGEN

Method 2.6.2 - DETERMINATION OF DIFFERENT FORMS OF NITROGEN IN FERTILIZERS CONTAINING NITROGEN ONLY AS NITRIC AMMONIACAL AND UREA NITROGEN

Methods 3 - PHOSPHORUS

Methods 3.1 - EXTRACTIONS

Method 3.1.1 - EXTRACTION OF PHOSPHORUS SOLUBLE IN MINERAL ACIDS

Method 3.1.2 - EXTRACTION OF THE PHOSPHORUS SOLUBLE IN 2 % FORMIC ACID (20 g per litre)

Method 3.1.3 - EXTRACTION OF PHOSPHORUS SOLUBLE IN 2 % CITRIC ACID (20 g per litre)

Method 3.1.4 - EXTRACTION OF PHOSPHORUS WHICH IS SOLUBLE IN NEUTRAL

AMMONIUM CITRATE

Methods 3.1.5 - EXTRACTION BY ALKALINE AMMONIUM CITRATE

Method 3.1.5.1 - Extraction of soluble phosphorus according to Petermann at 65 °C

Method 3.1.5.2 - Extraction of the soluble phosphorus according to Petermann at ambient temperature

Method 3.1.5.3 - Extraction of the phosphorus soluble in Joulie's alkaline ammonium citrate

Method 3.1.6 - EXTRACTION OF WATER SOLUBLE PHOSPHORUS

Method 3.2 - DETERMINATION OF EXTRACTED PHOSPHORUS (Gravimetric Method using quinoline phosphomolybdate)

Method 4 - POTASSIUM

Method 4.1 - DETERMINATION OF THE WATER SOLUBLE POTASSIUM CONTENT

Method 5

Method 6 - CHLORINE

Method 6.1 - DETERMINATION OF CHLORIDES IN THE ABSENCE OF ORGANIC

MATERIAL

Methods 7 - FINENESS OF GRINDING

Method 7.1 - DETERMINATION OF FINENESS OF GRINDING (dry procedure)

Method 7.2 - DETERMINATION OF THE FINENESS OF GRINDING OF SOFT NATURAL

PHOSPHATES

Methods 8 - SECONDARY NUTRIENTS

Method 8.1 - EXTRACTION OF TOTAL CALCIUM, TOTAL MAGNESIUM, TOTAL

SODIUM AND TOTAL SULPHUR IN THE FORM OF SULPHATES

Method 8.2 - EXTRACTION OF TOTAL SULPHUR PRESENT IN VARIOUS FORMS

Method 8.3 - EXTRACTION OF WATER-SOLUBLE CALCIUM, MAGNESIUM, SODIUM AND SULPHUR (in the form of sulphates)

Method 8.4 - EXTRACTION OF WATER-SOLUBLE SULPHUR WHERE THE SULPHUR

IS IN VARIOUS FORMS

Method 8.5 - EXTRACTION AND DETERMINATION OF ELEMENTAL SULPHUR

Method 8.6 - MANGANIMETRIC DETERMINATION OF EXTRACTED CALCIUM FOLLOWING PRECIPITATION IN THE FORM OF OXALATE

Method 8.7 - DETERMINATION OF MAGNESIUM BY ATOMIC ABSORPTION SPECTROMETRY

Method 8.8 - DETERMINATION OF MAGNESIUM BY COMPLEXOMETRY

Method 8.9 - DETERMINATION OF SULPHATES

Method 8.10 - DETERMINATION OF THE SODIUM EXTRACTED

Methods 9 - MICRO-NUTRIENTS at a concentration of less than or equal to 10%

Method 9.1 - EXTRACTION OF TOTAL MICRO-NUTRIENTS

Method 9.2 - EXTRACTION OF WATER-SOLUBLE MICRO-NUTRIENTS

Method 9.3 - REMOVAL OF ORGANIC COMPOUNDS FROM FERTILIZER EXTRACTS

Method 9.4 - DETERMINATION OF MICRO-NUTRIENTS IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY (general procedure)

Method 9.5 - DETERMINATION OF BORON IN FERTILIZER EXTRACTS BY MEANS OF SPECTROMETRY WITH AZOMETHINE-H

Method 9.6 - DETERMINATION OF COBALT IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY

Method 9.7 - DETERMINATION OF COPPER IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY

Method 9.8 - DETERMINATION OF IRON IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY

Method 9.9 - DETERMINATION OF MANGANESE IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY

Method 9.10 - DETERMINATION OF MOLYBDENUM IN FERTILIZER EXTRACTS BY SPECTROMETRY OF A COMPLEX WITH AMMONIUM THIOCYANATE

Method 9.11 - DETERMINATION OF ZINC IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY

Methods 10 - MICRO-NUTRIENTS AT A CONCENTRATION GREATER THAN 10 %

Method 10.1 - EXTRACTION OF TOTAL MICRO-NUTRIENTS

Method 10.2 - EXTRACTION OF WATER-SOLUBLE MICRO-NUTRIENTS

Method 10.3 - REMOVAL OF ORGANIC COMPOUNDS FROM FERTILIZER EXTRACTS

Method 10.4 - DETERMINATION OF MICRO-NUTRIENTS IN FERTILIZER EXTRACTS

BY ATOMIC ABSORPTION SPECTROMETRY (general procedure)

Method 10.5 - DETERMINATION OF BORON IN FERTILIZER EXTRACTS BY MEANS

OF ACIDIMETRIC TITRATION

Method 10.6 - DETERMINATION OF COBALT IN FERTILIZER EXTRACTS BY THE GRAVIMETRIC METHOD WITH 1-NITROSO-2-NAPHTHOL

Method 10.7 - DETERMINATION OF COPPER IN FERTILIZER EXTRACTS BY THE TITRIMETRIC METHOD

Method 10.8 - DETERMINATION OF IRON IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY

Method 10.9 - DETERMINATION OF MANGANESE IN FERTILIZER EXTRACTS BY TITRATION

Method 10.10 - DETERMINATION OF MOLYBDENUM IN FERTILIZER EXTRACTS BY THE GRAVIMETRIC METHOD WITH 8-HYDROXYQUINOLINE

Method 10.11 - DETERMINATION OF ZINC IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY

ANNEX V

A. List of documents to be consulted by manufacturers or their representatives in order to compile a technical file for a new type of fertilizers to be added to annex I of this regulation

B. Standards of accreditation concerning the laboratories that are competent and authorised to provide the necessary service for checking compliance of EC fertilizers with the requirements of this Regulation and its annexes

IMPACT ASSESSMENT FORM - DRAFT OF THE IMPACT OF THE PROPOSAL ON BUSINESS WITH SPECIAL REFERENCE TO SMALL AND MEDIUM-

SIZED ENTERPRISES (SMEs)

EXPLANATORY MEMORANDUM

1. General Comments

1.1. Policy

In the context of a people's Europe, the Commission attaches great importance to simplifying and clarifying Community law so as to make it more accessible to the ordinary citizen, thus giving him new opportunities and the chance to make use of the specific rights it gives him.

This aim cannot be achieved as long as numerous provisions that have been amended several times remain scattered, so that they must be sought partly in the original instrument and partly in later amending ones. Considerable research work, comparing many different instruments, is thus needed to identify the current rules.

For this reason, a consolidation of rules that have frequently been amended is essential if Community law is to be clear and transparent.

1.2. Directives concerned

The attached proposal of the Commission is a recast of Council and Commission Directives on the approximation of the laws of the Member States relating to fertilizers. It integrates within a single text the following Directives:

- Council Directive 76/116/EEC of 18 December 1975 on the approximation of the laws of the Member States relating to fertilizers;

- Council Directive 80/876/EEC of 15 July 1980 on the approximation of the laws of the Member States relating to straight ammonium nitrate fertilizers on high nitrogen content;

- Commission Directive 87/94/EEC of 8 December 1986 on the approximation of the laws of the Member States relating to procedures for the control of characteristics of, limits for and resistance to detonation of straight ammonium nitrate fertilizers of high nitrogen content;

- Commission Directive 77/535/EEC of 22 June 1977 on the approximation of the laws of the Member States relating to methods of sampling and analysis for fertilizers,

and the various amendments and adaptations to technical progress to these directives (see first whereas of the attached proposal).

1.3. Drafting Methodology and Structure

1.3.1. SLIM recommendations

Recommendations on what to include into the simplification of the fertilizer legislation were given by the Commission's SLIM II working group in its final report dated 27 October 1997. This, as well as all other points of relevance have been discussed in detail by the Commission's fertilizer working group (here: the working group), where experts from Member States and Industry gave their advice in altogether 13 days of meetings between March 1998 and December 2000. Implementation of this advice had to be guided by scientific, legal and pragmatic considerations. In particular, the SLIM group's recommendations to address certain issues in the recast have been taken into account as follows:

(a) Establishment of an ad-hoc group to advise the Commission For largest possible flexibility it is proposed to leave this to be organised by the Commission's working group on fertilizers on a case by case basis. Article 32 of the recast gives information on how to submit a proposal concerning fertilizers to the Commission.

(b) Criteria for the decision on new types of fertilizers (incl. organic). See Article 14.

(c) Requirements for types fertilizers to be added to the list. See Article 14.

(d) Requirement for mixtures of fertilizers according to compatibility. This is implicitly included in Article 14.

(e) Requirements for peer-reviewing of dossiers of new types of fertilizers with health and safety concerns. This is implicitly part of Article 14. The working group has agreed to decide on a case by case basis to ask for peer-reviewing of proposals.

(f) Conditions for adding new fertilizer groups. The working group has agreed that types of fertilizers of new fertilizer groups (e.g. organic) will only be considered after adoption of this recast and Article 14 provides for the necessity to define test methods.

(g) Controls by network of accredited laboratories and reports. Provisions are in Article 30, and whereas No 9.

(h) Study group on cadmium. This group has been established independently of the recast work, within the framework of the working group related to fertilizers, to permit consultations and discussions with Member States and interested parties. See transitional provisions, Article 33.

(i) Mixture of fertilizers. See Article 9a, last indent. Technical provisions for the identification of nutrients apply.

1.3.2. Structure

This recast has been structured in such a way as to exclude as far as possible all technical specifications from the legal text and instead include them into the annexes. Hence, as a guiding rule, the legal text was kept as general as possible. Undoubtedly, a "new approach" recast would have made things even easier. But that was neither the advice of the SLIM group, nor does it seem that there is, for the time being, enough common understanding on all the necessary standards for analysis. However, provisions [Article 29(4)] have been included to stimulate future adaptation to technical progress to be made in accordance with the "new approach".

In this draft, common provisions are separated from specific provisions. The latter ones are being ordered according to the main groups of fertilizers that are currently included in the legislation. This provides a rather simple way of using this legislation and adding other possible groups of fertilizers (e.g. organic fertilizers) without the need to restructure the whole instrument again.

The technical annexes have been compiled from the original Directives and rearranged. The working group has reviewed the annexes and has introduced some changes, however of a rather minor nature. In particular, technical specifications on nutrient contents have not been changed and tolerance levels have all been put into the annex. It was agreed that in the future a more detailed review of the specific technical requirements of the annexes would be needed in order to bring them up to date with state of the art analysis technology on fertilizers. However, experience of some Member Sates with their national fertilizer legislation showed that this would require several years. It was therefore decided to separate that work from this work on the recast.

The legal instrument chosen is that of a regulation. This is justified by the many adaptations to technical progress that this legislation has been and will be subjected to. In addition, a regulation imposes directly on manufacturers precise requirements to be implemented at the same time and in the same manner throughout the Community. Thus, it facilitates the tasks of the Member States and the economic operators and promotes a uniform application in the internal market.

1.4. Cadmium

1.4.1. The problem

Unintentional cadmium content in mineral fertilizers is a concern, in particular for Austria, Finland and Sweden who, since their accession to the Community, are allowed until 31 December 2001 to restrict the placing on the market of EC-fertilizers with a cadmium content above their national thresholds. No limit values exist on the European level and hence the European fertilizer legislation is currently not fully harmonised. The Commission has committed itself in 1998 to solve this problem by the end of 2001 and has together with the Member States initiated and conducted a risk assessment programme of cadmium in fertilizers.

1.4.2. Strategy

When the risk assessment programme is terminated, the Commission will make a proposal on what measures should be taken, if any, at Community level.

The current recast does therefore not address the cadmium issue, it is limited to the more technical process of recasting the present law. It should therefore be possible to adopt it rapidly. This is all the more necessary as it provides for a transitory period of two years during which the problem of cadmium can be resolved. Afterwards, a similar review on other contaminants will be performed in case that their presence would adversely affect human, animal or plant health, or the environment.

2. Specific Comments

The structure of the recast is indicated by its table of contents.

Much of the text has been copied from the old directives, but rearranged to fit to the structure. Use was made of all the articles of the old directives except in cases of redundancy. Whenever possible, the wording of the old directives has been used.

Article 2 For the most important terms definitions have been introduced, most of them are equivalent to those used by CEN, some have been altered following the advice of the expert working group.

Articles 3 The designation "EC fertilizer" is reserved for those fertilizers complying with this Regulation.

Article 4 Emphasis was put on ensuring that the responsibilities of the person who places the fertilizer on the market are clearly spelled out.

Article 5 This Article enunciates the principle of free circulation in the internal market.

Article 6 Articles of the old directives defining general requirements for the declarations of all types of nutrients have been integrated in this article.

Articles 7-12 Labelling and packaging requirements were taken over almost unchanged from the old directives.

Article 13 This Article relates to the tolerances for the declared contents of nutrients. In Annex II of this Regulation it is made clear that the tolerances are meant to be negative values only. Paragraph 2 specifies the obligations of the manufacturers. Paragraph 3 was copied from the technical Annex III of Directive 76/116/EEC.

Article 14 This Article defines the general requirements that a type of fertilizer must fulfil for Annex I inclusion, introducing explicitly the notion of presenting analysis methods in a proposal.

Article 15 The safeguard clause was hitherto only part of Directive 80/876/EEC concerning the approximation of the laws of the Member Sates relating to straight ammonium nitrate fertilizers of high nitrogen content. It is now applicable to the entire EC fertilizer legislation.

Articles 16-19 Scope, declaration and identification provisions have been included here for the specific types of fertilizers as indicated. They have been copied from the old directives with changes in order to simplify and improve clarity.

Articles 20, 21 Similar as in Articles 16-19, specific requirements for these particular types of fertilizers are defined.

Articles 22, 23 Ibid.

Article 24 As in the previous Directive

Articles 25-28 The scope has been expanded from straight to compound ammonium nitrate fertilizers, of high nitrogen content in order to take into account the new market situation. According to the old legislation compounds would not be subject to detonation tests thus creating a loop hole that Members States wanted to close because of safety and security reasons.

Hence the detonation test can now be required by Member States also for compound Ammonium Nitrate fertilizer of high nitrogen content. If an EC fertilizer satisfies the requirement of the test of resistance to detonation mentioned in Annex III of this Regulation, it should be subject to less stringent national provisions, in particular as regards storage.

Article 29 This Article on compliance provisions includes provisions to use, whenever possible, European standards for adaptation to technical progress of analysis methods, introducing the new approach to future legislation in this sector.

Article 30 This is new and provides for a better framework for analysis and testing. The SLIM group and Member States saw the need to introduce a quality assurance scheme for laboratories. Because of the diverse situation in Member states transitional measure have been introduced as well (see Article 34).

Article 31 Provisions are defined on what to do when applying for Annex I inclusion of a new type of fertilizer.

Article 32 The relevant Comitology according to Council Decision 1999/468/EC.

Articles 33, 34 Transitional provisions, partly from existing directives and partly as indicated under Article 30. The derogation for Austria, Finland and Sweden mentioned in Article 33 has been prolonged till 31 December 2004 in order to allow sufficient time for Community measures on cadmium to be decided.

Articles 35-38 Final provisions.

2001/0212 (COD)

Proposal for a

REGULATION OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL

relating to fertilizers

(Text with EEA relevance)

THE EUROPEAN PARLIAMENT AND THE COUNCIL OF THE EUROPEAN UNION,

Having regard to the Treaty establishing the European Community, and in particular Article 95 thereof,

Having regard to the proposal from the Commission [1],

[1] OJ C

Having regard to the opinion of the Economic and Social Committee [2],

[2] OJ C

Acting in accordance with the procedure laid down in Article 251 of the Treaty [3],

[3] OJ C

Whereas:

(1) Council Directive 76/116/EEC of 18 December 1975 on the approximation of the laws of the Member States relating to fertilizers [4], as last amended by Directive 98/97/EC of the European Parliament and the Council [5], Council Directive 80/876/EEC of 15 July 1980 on the approximation of the laws of the Member States relating to straight ammonium nitrate fertilizers of high nitrogen content [6], as amended by Directive 97/63/EC of the European Parliament and the Council [7], Commission Directive 87/94/EEC of 8 December 1986 on the approximation of the laws of the Member States relating to procedures for the control of characteristics of, limits for and resistance to detonation of straight ammonium nitrate fertilizers of high nitrogen content [8], as amended by Directive 88/126/EEC [9] and Commission Directive 77/535/EEC of 22 June 1977 on the approximation of the laws of the Member States relating to methods of sampling and analysis for fertilizers [10], as last amended by Directive 95/8/EC [11], have been substantially amended several times. In accordance with the communication from the Commission to the Council and the European Parliament "Simpler legislation for the internal market" [12] (SLIM) and the Action Plan for the Single Market [13] those Directives should be repealed and replaced by a single legal instrument, in the interests of clarity.

[4] OJ L 24, 30.1.1976, p. 21.

[5] OJ L 18, 23.1.1999, p. 60.

[6] OJ L 250, 23.9.1980, p. 7.

[7] OJ L 335, 6.12.1997, p. 15.

[8] OJ L 38, 7.2.1987, p. 1.

[9] OJ L 63, 9.3.1988, p. 12.

[10] OJ L 213, 22.8.1977, p. 1.

[11] OJ L 86, 20.4. 1995,p. 41.

[12] COM(96) 204 final.

[13] CSE(97) 1 final.

(2) The Community legislation on fertilizers is very technical in its content. A Regulation is therefore the more appropriate legal instrument as it imposes directly on manufacturers and importers precise requirements to be applied at the same time and in the same manner throughout the Community.

(3) In each Member State fertilizers must display certain technical characteristics laid down by mandatory provisions. These provisions, concerning more particularly the composition and definition of fertilizers types, the designations of these types, their identification and their packaging, differ from one Member State to another. By their disparity they hinder trade within the Community. They should therefore be harmonised.

(4) Since the objectives of the proposed action namely to ensure the internal market in fertilizers, cannot be sufficiently achieved by the Member States if there are no common technical criteria and can therefore, by reason of the scale of the action, be better achieved at Community level, the Community may adopt measures, in accordance with the principle of subsidiarity as set out in Article 5 of the Treaty. In accordance with the principle of proportionality, as set out in that Article, this regulation does not go beyond what is necessary in order to achieve those objectives.

(5) It is necessary to determine at Community level the designation, definition and composition of EC fertilizers.

(6) Community rules on the identification and labelling of these fertilizers, and on the closure of the packages should also be laid down.

(7) A procedure should be established at Community level to be followed in cases where a Member State deems it necessary to restrict the placing on the market of EC fertilizers.

(8) The production of fertilizers is subject to varying degrees of fluctuation due to manufacturing techniques or basic materials. Sampling and analytical procedures may also contain variations. It is therefore necessary to authorise tolerances on the declared nutrient contents. In the interest of the agricultural user, it is advisable to keep these tolerances within narrow limits.

(9) Official controls on the compliance of EC fertilizers with requirements of this Regulation concerning quality and composition should be carried out by competent laboratories.

(10) Ammonium nitrate is the essential ingredient of a variety of products, some of which are intended for use as fertilizers and others as explosives. I It is necessary, having regard to the particular nature of ammonium nitrate fertilizers of high nitrogen content and to the requirements it entails regarding public safety, health and protection of workers, to lay down additional Community rules for EC fertilizers of this type.

(11) Certain of those products could be hazardous and could in certain instances be used for purposes other than those for which they were intended. This could well endanger the security of persons and property. Member States should therefore not be prevented from taking appropriate steps to avoid such use.

(12) In the interest of public safety, it is particularly important to determine at Community level the characteristics and properties distinguishing ammonium nitrate EC fertilizers of high nitrogen content from varieties of ammonium nitrate used in the manufacture of products used as explosives

(13) Ammonium nitrate EC fertilizers of high nitrogen content should conform to certain characteristics to ensure that they are harmless. Member States should be able to subject such fertilizers to a test of resistance to detonation before or after they are placed on the market. If an EC fertilizer satisfies the requirement of the test of resistance to detonation, it should be subject to less stringent national provisions, in particular as regards storage.

(14) It is necessary to establish rules on the methods of the closed thermal cycles even if these methods may not necessarily simulate all conditions arising during transport and storage.

(15) Fertilizers can be contaminated by substances that can potentially pose a risk to human and animal health and the environment. The issue of unintentional cadmium content in mineral fertilizers is the first of these substances that will be addressed by the Commission. Where appropriate, a similar review will be undertaken for other contaminants.

(16) It is appropriate to establish a procedure, to be observed by any manufacturer or his representative wanting to include a new type of fertilizer into Annex I in order to apply to a fertilizer the marking "EC FERTILIZER". This procedure should include the submission of a technical file to a Member State authority which will act as rapporteur for the file.

(17) Since the measures necessary for the implementation of this Regulation are measures of general scope within the meaning of Article 2 of Council Decision 1999/468/EC of 28 June 1999 laying down the procedures for the exercise of implementing powers conferred on the Commission [14], they should be adopted by use of the regulatory procedure provided for in Article 5 of that Decision.

[14] OJ L 184, 17.7.1999, p. 23.

(18) Member States should lay down penalties in respect of infringements to the provisions of this Regulation,

HAVE ADOPTED THIS REGULATION:

TItLE I General provisions

Chapter I Scope and Definitions

Article 1

This Regulation shall apply to products which are placed on the market as fertilizers designated "EC fertilizer".

Article 2

For the purpose of this Regulation the following definitions shall apply:

(a) Fertilizer means material, the main function of which is to provide nutrients for plants.

(b) Primary nutrient means the elements nitrogen, phosphorus and potassium only.

(c) Secondary nutrient means the elements calcium, magnesium, sodium and sulphur.

(d) Micro-nutrients means the elements boron, cobalt, copper, iron, manganese, molybdenum and zinc, essential for plant growth in quantities small compared to those of primary and secondary nutrients.

(e) Inorganic fertilizer means a fertilizer in which the declared nutrients are in the form of minerals obtained by physical and/or chemical industrial processes. Calcium cyanamide, urea and its condensation and association products may, by convention, be classed as inorganic fertilizers.

(f) Chelated micro-nutrient means a micro-nutrient that is held by one of the organic molecules listed in section E.3.1 of Annex I.

(g) Complexed micro-nutrient means a micro-nutrient that is held by one of the molecules listed in section E.3.2 of Annex I.

(h) Type of fertilizers means fertilizers with a common type designation as indicated in Annex I.

(i) Straight fertilizer means anitrogenous, phosphatic or potassic fertilizer having a declarable content of only one of the primary nutrients.

(j) Compound fertilizer means a fertilizer having a declarable content of at least two of the primary nutrients and obtained chemically or by blending or by a combination of both.

(k) Complex fertilizer means a compound fertilizer, obtained by chemical reaction, by solution, or in its solid state by granulation, having a declarable content of at least two of the primary nutrients. In its solid state each granule contains all the nutrients in their declared composition.

(l) Blended Fertilizer means a fertilizer obtained by dry mixing of several fertilizers, with no chemical reaction.

(m) Foliar fertilizer means a fertilizer designed for application to and nutrient uptake by the foliage of a crop.

(n) Fluid fertilizer means fertilizers in suspension or solution.

(o) Solution fertilizer means a fluid fertilizer, that is free of solid particles.

(p) Suspension fertilizer means a two-phase fertilizer in which solid particles are maintained in suspension in the liquid phase.

(q) Declaration means a statement of the amount of nutrients or of their oxides, including their forms and solubility, guaranteed within specified tolerances.

(r) Declarable content means the content of a nutrient, or its oxide, which according to Community legislation, may or shall be given on a label or document associated with an EC fertilizer.

(s) Tolerance means the permitted deviation of the measured value of a nutrient content from its declared value.

(t) Harmonised European Standard means CEN (European Committee for Standardisation) standards, which have been officially recognised by the Community and whose reference has been published in the Official Journal of the European Communities

(u) Package means a sealable receptacle used to hold, protect, handle, and distribute fertilizers and holding not more than 1 000 kg.

(v) Bulk means a fertilizer not packaged as prescribed by this Regulation.

(w) Placing on the market means any supply, whether in return for payment or free of charge, or storage for the purpose of supply. Importation of a fertilizer into the customs territory of the Community shall be deemed to constitute placing on the market for the purposes of this Regulation.

(x) Manufacturer means the natural or legal person, including importers, placing a fertilizer on the market.

Chapter ii Placing on the market

Article 3

A fertilizer belonging to a type of fertilizers listed in Annex I and which complies with the conditions laid down in this Regulation, may be designated "EC fertilizer".

The manufacturer shall not use the designation "EC fertilizer" for fertilizers that do not comply with this Regulation.

Article 4

The manufacturer shall be established within the Community and shall be responsible for the conformity of the "EC fertilizer" with the provisions of this Regulation.

Article 5

1. Without prejudice to the provisions of Article 15 and of other Community legislation, Member States shall not, on grounds of composition, identification, labelling or packaging, and other provisions contained in this Regulation, prohibit, restrict or hinder the placing on the market of fertilizers marked "EC fertilizer" which comply with the provisions of this Regulation.

2. Fertilizers that are marked "EC fertilizer" in accordance with this Regulation shall circulate freely within the Community.

Article 6

1. In order to satisfy the requirements of Article 9, Member States may prescribe that the indication of the nitrogen, phosphorus and potassium contents of fertilizers placed on their market is to be expressed in the following way:

(a) nitrogen solely in the elemental form (N);

(b) phosphorus and potassium solely in the elemental form (P, K);

(c) phosphorus and potassium solely in the oxide form (P2O5, K2O);

(d) phosphorus and potassium in both elemental and oxide forms simultaneously.

Where the option is chosen to prescribe that the phosphorus and potassium contents be expressed in the form of elements, all references in the Annexes to the oxide form shall read as being in elemental form and the numerical values converted using the following factors:

(a) phosphorus (P) = phosphorus pentoxide (P2O5) ( 0.436;

(b) potassium (K) = potassium oxide (K2O) ( 0.830.

2. Member States may prescribe that the calcium, magnesium, sodium and sulphur contents of secondary nutrient fertilizers and, where the conditions of Article 17 are fulfilled, of primary nutrient fertilizers placed on their markets are to be expressed:

(a) in the oxide form (CaO, MgO, Na2O, SO3);

(b) or in the elemental form (Ca, Mg, Na, S);

(c) or in both of these forms.

To convert the calcium oxide, magnesium oxide, sodium oxide and sulphur trioxide contents into calcium, magnesium, sodium and sulphur contents, the following factors shall be used:

(a) calcium (Ca) = calcium oxide (CaO) ( 0.715;

(b) magnesium (Mg) = magnesium oxide (MgO) ( 0.603;

(c) sodium (Na) = sodium oxide (Na2O) ( 0.742;

(d) sulphur (S) = sulphur trioxide (SO3) ( 0.400.

For the calculated oxide or elemental content, the figure declared shall be rounded to the nearest decimal place.

3. The Member States cannot prevent a manufacturer from choosing to label an "EC fertilizer" in both of the forms mentioned in paragraphs 1 and 2 respectively.

4. The content of one or more of the micro-nutrients boron, cobalt, copper, iron, manganese, molybdenum, or zinc in the EC fertilizers belonging to the types of fertilizers listed in sections A, B, C and D of Annex I shall be declared where the following conditions are fulfilled:

(a) the micro-nutrients are added at least in the minimum quantities specified in section E.2.2 and E .2.3 of Annex I;

(b) the EC fertilizer continues to satisfy the requirements of sections A, B, C and D of Annex I.

5. Where the micro-nutrients are the normal ingredients of the raw materials intended to supply primary (N, P, K) and secondary (Ca, Mg, Na, S) nutrients, they may be declared, provided that these micro-nutrients are present at least in the minimum quantities specified in sections E.2.2 and E.2.3 of Annex I.

6. The micro-nutrient content shall be declared in the following manner:

(a) for fertilizers belonging to the types of fertilizers listed in section E.1 of Annex I in accordance with the requirements set out in column 6 of that section;

(b) for mixtures of fertilizers referred to in (a) containing at least two different micro-nutrients and meeting the requirements of section E.2.1 of Annex I and for fertilizers belonging to the types of fertilizers listed in sections A, B, C and D of Annex I by indicating:

(i) the total content, expressed as a percentage of the fertilizer by mass,

(ii) the water-soluble content, expressed as a percentage of the fertilizer by mass, where the soluble content is at least half of the total content.

Where a micro-nutrient is totally water-soluble, only the water-soluble content shall be declared.

Where a micro-nutrient is chemically linked with an organic molecule the content present in the fertilizer shall be declared immediately following the water- soluble content as a percentage by mass of the product, followed by one of the terms "chelated by", or "complexed by" with the name of the organic molecule as set out in section E.3 of Annex I. The name of the organic molecule may be replaced by its initials.

Article 7

1. Manufacturers shall provide EC fertilizers with the identification markings listed in Article 9.

2. If the fertilizers are packed, these identification markings shall appear on the packages or labels attached. If the fertilizers are in bulk, these markings must appear on the accompanying documents.

Article 8

Member States may require on their territory without impeding trade and under the responsibility of the manufacturer, that an indication be given of the dose rates and conditions of use suitable for the soil and crop conditions under which the fertilizer is used. This information must be clearly separated from the compulsory indications provided for in Articles 9, 19, 21 and 23.

Article 9

1. Without prejudice to other Community rules, the only statutory markings relating to fertilizers and permitted on the packages, labels and accompanying documents referred to in Article 7 shall be the following indications:

(a) Compulsory identification

- The words "EC FERTILIZER" in capital letters;

- The additional markings specified in Article 19, 21 or 23;

- Nutrients shall be indicated both in words and by the appropriate chemical symbols, e.g. nitrogen (N), phosphorus (P), phosphorus pentoxide (P2O5), potassium (K), potassium oxide (K2O), calcium (Ca), calcium oxide (CaO), magnesium (Mg), magnesium oxide (MgO), sodium (Na), sodium oxide (Na2O), sulphur (S), sulphur trioxide (SO3), boron (B), copper (Cu), cobalt (Co), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn);

- If the fertilizer contains micro-nutrients of which all or part are chemically linked with an organic molecule, the name of the micro-nutrient shall be followed by one of the following qualifiers:

(i) "chelated by ..." (name of chelating agent or its abbreviation as set out in section E.3.1 of Annex I),

(ii) "complexed by ..." (name of complexing agent as set out in section E.3.2 of Annex I);

- Micro-nutrients contained in the fertilizer, listed in the alphabetical order of their chemical symbols: B, Co, Cu, Fe, Mn, Mo, Zn;

- Quantities of fluid fertilizers, expressed by mass. The expression of quantities of fluid fertilizers by volume or in terms of mass versus volume (kilograms per hectolitre or grams per litre) shall be optional;

- Net or gross mass, and optionally volume for fluid fertilizers;

- If the gross mass/volume is given, the tare mass/volume must be indicated beside it;

- The name or trade name or trade mark and the address of the manufacturer;

- For blended fertilizers the marking "blend" after the designation of the type.

(b) Optional identification

- As listed in Annex I;

- The specific directions for the use, storage, and handling of the fertilizer;

- The manufacturer's own mark, the trademark of the product and the trade description of the product.

The characteristics referred to in (b) must not conflict with those referred to in (a) and must be clearly separated from them.

2. All the markings referred to in Paragraph 1 must be clearly separated from any other information on the packages, labels and accompanying documents

3. Fluid fertilizers may be placed on the market only if suitable additional instructions are provided by the manufacturer. These instructions shall cover, in particular, storage temperature and prevention of accidents during storage.

Article 10

1. The labels or markings printed on the package and giving the particulars mentioned under Article 9 must be placed in a conspicuous position. Attached labels must be held in place by whatever system is used for closing the package. If this system consists of a seal, that seal must bear the name or mark of the manufacturer.

2. The markings referred to in Paragraph 1 must be and must remain indelible and clearly legible.

3. In the cases referred to in Article 7(2) a copy of the documents containing the identification markings must accompany the goods and be accessible for inspection purposes.

Article 11

Member States may require that on their territory the label, the markings on the package and the accompanying documents shall appear in at least their national language or languages.

Article 12

In the case of packaged EC fertilizers, the package must be closed in such a way or by such a device that, when it is opened, the fastening, fastening seal or the package itself is irreparably damaged. Valve sacks may be used.

Article 13

1. The declared contents of nutrients of EC fertilizers shall comply with the tolerance limits established in Annex II.

2. A manufacturer shall not take systematic advantage of the tolerances given in Annex II

3. No tolerances are allowed in respect of the minimum and maximum contents specified in Annex I.

Article 14

A type of fertilizer shall only be included into Annex I if:

(a) Under normal conditions of use it does not adversely affect human, animal, or plant health, or the environment;

(b) It provides nutrients in an effective manner;

(c) Relevant sampling, analysis, and if required, test methods are being provided.

Article 15

1. Where a Member State has justifiable grounds for believing that a specific EC fertilizer, although satisfying the requirements of this Regulation, constitutes a risk to safety or health of humans or of animals or a risk to the environment, it may temporarily prohibit the placing on the market of that fertilizer in its territory or make it subject to special conditions. It shall immediately inform the other Member States and the Commission thereof, giving the reasons for its decision.

2. The Commission shall, within six weeks from the receipt of the information, consult the Member States and if appropriate shall without undue delay consult the relevant technical or scientific committee of the Commission. The Commission shall inform the Member States about the conclusions of the said committee.

3. After consultation of the Member States, or if appropriate of the relevant technical or scientific committee of the Commission, a decision shall be taken on the matter within 90 days in accordance with the procedure referred to in Article 32(2).

4. The provisions of this Regulation shall not preclude the taking of measures which are justified on grounds of public security to prohibit, restrict or hinder the placing on the market of EC fertilizers.

Title II provisions for specific types of fertilizers

Chapter I Inorganic primary nutrient fertilizers

Article 16

This chapter shall apply to inorganic primary nutrient fertilizers, solid or fluid, straight or compound, including those containing secondary nutrients or micro-nutrients, with the minimum nutrient content established in sections A, B, C, E.2.2 or E.2.3 of Annex I.

Article 17

1. A declaration of the calcium, magnesium, sodium and sulphur content as secondary nutrient content of the EC fertilizers belonging to the types of fertilizers listed in sections A, B and C of Annex I may be made, provided that the EC fertilizer continues to satisfy the requirements set out in those sections and that these elements are present in at least the following minimum quantities:

(a) 2 % calcium oxide (CaO), i.e. 1.4 % Ca;

(b) 2 % of magnesium oxide (MgO), i.e. 1.2 % Mg;

(c) 3 % of sodium oxide (Na2O), i.e. 2.2 % Na;

(d) 5 % of sulphur trioxide (SO3), i.e. 2 % S.

In such a case, the additional marking specified in Article 19(2)(ii), shall be added to the type designation.

2. Unless otherwise specified in Annex I a declaration of the calcium content shall only be made if it is soluble in water.

Article 18

The declaration of the calcium, magnesium, sodium and sulphur content of the fertilizers listed in sections A, B, and C of Annex I shall be expressed in one of the following ways:

(a) the total content expressed as a percentage of the fertilizer by mass;

(b) the total content and the content soluble in water, expressed as a percentage of the fertilizer by mass where the soluble content is at least a quarter of the total content;

(c) where an element is totally soluble in water, only the content soluble in water shall be declared as a percentage of the mass.

Article 19

1. In addition to the compulsory identification markings referred to in Article 9(1)(a) the markings set out in paragraphs 2, 3 and 4 of this Article shall be stated.

2. The designation of the type of fertilizer shall be stated, in accordance with Annex I with, in brackets and immediately following the chemical symbols of the primary nutrients, the chemical symbols of the declared secondary nutrients, which the fertilizer contains.

The nutrient content shall be given by:

(i) numbers indicating the primary nutrient content which, for compound fertilizers, should be in the order laid down by the said designation;

(ii) numbers, in brackets, indicating the contents for the declared secondary nutrients followed:

- by the words "with micro-nutrients" if there is a declared content of micro-nutrients, or

- by the word "with" followed by the name or names of the micro-nutrients present or by their chemical symbols.

Only numbers stating the contents of primary and secondary nutrients shall follow the type designation.

3. The declared content of primary nutrients and secondary nutrients shall be given as a percentage by mass, as whole numbers or, where necessary, to one decimal place.

For compound fertilizers the order shall be for primary nutrients: N, P2O5 and/or P, K2O and/or K, and for secondary nutrients: CaO and/or Ca, MgO and/or Mg, Na2O and/or Na, SO3 and/or S.

The declared content of micro-nutrients shall be given as a percentage by mass as specified in sections E.2.2 and E.2.3 of Annex I.

4. The forms and solubility of the nutrients shall also be expressed as a percentage by mass of fertilizer, except where Annex I explicitly provides that this content shall be otherwise expressed.

The number of decimal places shall be one, except for micro-nutrients where it shall be as specified in sections E.2.2 and E.2.3 of Annex I.

Chapter II Inorganic secondary nutrient fertilizers

Article 20

This chapter shall apply to inorganic secondary nutrient fertilizers, solid or fluid, including those containing micro-nutrients, with the minimum nutrient content established in sections D, E.2.2, and E.2.3 of Annex I.

Article 21

1. In addition to the compulsory identification markings referred to in Article 9(1)(a) the markings set out in paragraphs 2, 3 and 4 of this Article shall be stated.

2. The designation of the type of fertilizer shall be stated in accordance with section D of Annex I.

The nutrient content shall be given by numbers indicating the contents of the declared secondary nutrients followed:

(i) by the words "with micro-nutrients" if there is a declared content of micro-nutrients, or

(ii) by the word "with" followed by the name or names of the micro-nutrients present or by their chemical symbols.

Only numbers stating the contents of secondary nutrients shall follow the type designation.

3. The declared content of secondary nutrients shall be given as a percentage by mass, as whole numbers or, where necessary, to one decimal place.

For compound fertilizers the order shall be:

CaO and/or Ca, MgO and/or Mg, Na2O and/or Na, SO3 and/or S.

The declared content of micro-nutrients shall be given as a percentage by mass as specified in sections E.2.2 and E.2.3 of Annex I.

4. The forms and solubility of the nutrients shall also be expressed as a percentage by mass of fertilizer, except where Annex I explicitly provides that this content shall be otherwise expressed.

The number of decimal places shall be one, except for micro- nutrients where it shall be as specified in sections E.2.2 and E.2.3 of Annex I.

Chapter III Inorganic micro-nutrient fertilizers

Article 22

This chapter shall apply to inorganic micro-nutrient fertilizers, solid or fluid, with the minimum nutrient content established in sections E.1 and E.2.1 of Annex I.

Article 23

1. In addition to the compulsory identification markings referred to in Article 9(1)(a) the markings set out in paragraphs 2, 3, 4 and 5 of this Article shall be stated.

2. The designation of the type of fertilizer shall be stated:

(a) either in accordance with section E.1 of Annex I, or

(b) as the type designation "mixture of micro-nutrients", followed by the names of the micro-nutrients present or their chemical symbols.

3. The declared micro-nutrient content shall be given as a percentage by mass, in whole numbers or, where necessary, to one decimal places for fertilizers containing only one micro-nutrient shown in section E.1 of Annex I.

Where fertilizers contain several micro-nutrients, the number of decimal places may, for a given element, be as set out in section E.2.1 of Annex I.

4. The forms and solubility of micro-nutrients shall be expressed as a percentage by mass of fertilizer, except where Annex I explicitly provides that this content shall be otherwise expressed.

The number of decimal places of micro-nutrient contents for mixtures of micro-nutrients shall be as specified in section E.2.1 of Annex I.

5. Below the obligatory or optional declarations the following shall be entered on the label and accompanying papers with regard to the products appearing in sections E.1 and E.2.1 of Annex I:

"To be used only where there is a recognised need. Do not exceed the appropriate dose rates."

Article 24

EC fertilizers covered by the provisions of this chapter shall be packaged.

Chapter IV Ammonium nitrate fertilizers of high nitrogen content

Article 25

For the purpose of this chapter, ammonium nitrate fertilizers of high nitrogen content, straight or compound, are ammonium nitrate based products manufactured for use as fertilizers and containing more than 28 % by mass of nitrogen in relation to ammonium nitrate.

This type of fertilizer may contain inorganic or inert substances.

Any substances that are used in the manufacturing of this type of fertilizers, must not increase its sensitivity to heat or its tendency to detonate.

Article 26

1. Manufacturers shall ensure that straight ammonium nitrate fertilizers of high nitrogen content comply with the provisions of section 1 of Annex III.

2. The checking, analysis and testing for official controls of straight ammonium nitrate fertilizers of high nitrogen content provided for by this Chapter shall be carried out in accordance with the methods described in section 3 of Annex III.

Article 27

1. Without prejudice to the measures referred to in Article 26, Member States may require additional checks on ammonium nitrate EC fertilizers of high nitrogen content. Such checks may be carried out either before the fertilizers are placed on the market within their territories, or after marketing, or at both stages .

For these checks, only the test described in section 2 of Annex III shall be used.

2. EC fertilizers which satisfy the requirements of this chapter and, where required by the Member State, the test of resistance to detonation described in section 3 (Method 1, point 3) and 4 of Annex III, shall not be subject to national rules which apply to less safe fertilizers and their storage.

Article 28

Straight ammonium nitrate fertilizers of high nitrogen content shall be made available to the final user only in packaged form.

Title III conformity assessment of fertilizers

Article 29

1. Member States may subject fertilizers placed on the market with the marking "EC FERTILIZER" to official control measures, for the purpose of verifying that they comply with this Regulation. These control measures shall not oblige manufacturers to repeat tests made by laboratories fulfilling the conditions of Article 30 in so far as these tests have shown compliance of the fertilizer in question.

2. Member States shall ensure that sampling and analysis for official controls of EC fertilizers belonging to types of fertilizers listed in Annex I are carried out in accordance with the methods described in Annex IV.

3. Compliance with this Regulation in respect of conformity to types of fertilizer and compliance with the declared nutrient content and/or the declared content expressed as forms and solubilities of such nutrients may be verified at official inspections only by means of sampling and analysis methods established in accordance with Annex IV and taking into account the tolerances specified in Annex II.

4. Adaptation to technical progress of sampling and analysis methods shall follow the procedure referred to in Article 32(2), and shall, wherever possible, use Harmonised European Standards.

Article 30

1. Member States shall notify to the Commission those laboratories on their territories that are competent and authorised to provide the necessary services for checking compliance of EC fertilizers with the requirements of this Regulation

2. Member States shall demonstrate the competence of the notified laboratories referred to under Paragraph 1 either by accreditation, according to the standards mentioned in Annex V, or by certifying them to comply with the requirements of Council Directive 87/18/EEC [15].

[15] OJ L 15, 17.1. 1987, p. 29.

3. The Commission shall publish the list of notified laboratories in the Official Journal of the European Communities.

4. Where a Member State has justifiable grounds for believing that a notified laboratory does not possess the competence referred to in Paragraph 2 of this article, it shall raise this matter in the committee referred to in Article 32(1). Article 15(2) shall apply mutatis mutandis.

Title IV FINAL provisions

Chapter I Adaptation of the annexes

Article 31

1. The inclusion of a new type of fertilizer into Annex I of this Regulation shall be adopted in accordance with the procedure referred to in Article 32(2). This procedure requires the submission of a technical file to a Member State authority which will act as rapporteur for the file to the committee referred to in Article 32(1).

2. A manufacturer or its representative wanting to propose a new type of fertilizer to be added to Annex I and to this effect needs to compile a technical file, shall do so by taking into account the technical documents referred to in Annex V.

3. Amendments required to adapt the Annexes to technical progress shall be adopted in accordance with the procedure referred to in Article 32(2).

Article 32

1. The Commission shall be assisted by a committee, composed of representatives of the Member States and chaired by the representative of the Commission.

2. Where reference is made to this paragraph, the regulatory procedure laid down in Article 5 of Decision 1999/468/EC shall apply, in compliance with Article 7 and Article 8 thereof.

3. The period provided for in Article 5(6) of Decision 1999/468/EC shall be three months.

Chapter II Transitional provisions

Article 33

1. By way of derogation from Article 5, Austria, Finland and Sweden may prohibit the placing on the market on their territory of EC fertilizers containing cadmium at concentrations in excess of those which were fixed nationally at the date of Accession until 31 December 2004.

2. The Commission shall, in consultation with Member States and interested parties, review by 30 June 2002 at the latest the need for establishing provisions at Community level concerning the cadmium content of fertilizers.

Article 34

1. Without prejudice to the provisions of Article 30(2), Member States may, for a transitional period until 31 December 2006 continue to apply their national provisions for authorising competent laboratories to provide the necessary services for checking compliance of EC fertilizers with the requirements of this Regulation.

2. Member States shall notify these laboratories to the Commission, giving details of their authorisation scheme.

Chapter III Final provisions

Article 35

Directives 76/116/EEC, 77/535/EEC, 80/876/EEC and 87/94/EEC are repealed.

Article 36

The Member States shall lay down the rules on penalties applicable to infringements of the provisions of this Regulation and shall take all measures necessary to ensure that they are implemented. The penalties provided for must be effective, proportionate and dissuasive. The Member States shall notify those provisions to the Commission by 31 December 2003 at the latest and shall notify it without delay of any subsequent amendment affecting them.

Article 37

By 31 December 2006 at the latest, the Commission will review the way in which declarations have to be made under Article 6 with a view to proposing a single coherent system of declarations throughout the Community.

Article 38

This Regulation shall enter into force on the sixtieth day following that of its publication in the Official Journal of the European Communities.

This Regulation shall be binding in its entirety and directly applicable in all Member States.

Done at Brussels,

For the European Parliament For the Council

The President The President

ANNEX I List of types of EC fertilizers

A. Inorganic straight primary nutrient fertilizers

A.1. Nitrogenous fertilizers

>TABLE POSITION>

A.2. Phosphatic fertilizers

Where a particle size criterion is prescribed for the basic constituent materials of fertilizers sold in granular form (fertilizers 1, 3, 4, 5, 6 and 7), it will be established by an appropriate analytical method.

>TABLE POSITION>

A.3. Potassic fertilizers

>TABLE POSITION>

B. Inorganic compound primary nutrient fertilizers

B.1. NPK fertilizers

>TABLE POSITION>

>TABLE POSITION>

B.1. NPK fertilizer (continued)

>TABLE POSITION>

>TABLE POSITION>

B.2. NP fertilizers

>TABLE POSITION>

>TABLE POSITION>

B.2. NP fertilizers(continued)

>TABLE POSITION>

B.3. NK fertilizers

>TABLE POSITION>

>TABLE POSITION>

B.3. NK fertilizers (continued)

>TABLE POSITION>

>TABLE POSITION>

B.4. PK fertilizers

>TABLE POSITION>

>TABLE POSITION>

C. Inorganic fluid fertilizers

C.1. Straight fluid fertilizers

>TABLE POSITION>

C.2. Compound fluid fertilizers

>TABLE POSITION>

>TABLE POSITION>

C.2. Compound fluid fertilizers (continued)

>TABLE POSITION>

>TABLE POSITION>

C.2. Compound fluid fertilizers (continued)

>TABLE POSITION>

>TABLE POSITION>

C.2. Compound fluid fertilizers (continued)

>TABLE POSITION>

>TABLE POSITION>

C.2. Compound fluid fertilizers (continued)

>TABLE POSITION>

>TABLE POSITION>

C.2. Compound fluid fertilizers (continued)

>TABLE POSITION>

>TABLE POSITION>

C.2. Compound fluid fertilizers (continued)

>TABLE POSITION>

>TABLE POSITION>

C.2. Compound fluid fertilizers (continued)

>TABLE POSITION>

>TABLE POSITION>

D. Inorganic secondary nutrient fertilizers

>TABLE POSITION>

E. Inorganic micro-nutrient fertilizers

Explanatory note: The following notes are applicable to the whole of Part E.

Note 1: A chelating agent may be designated by means of its initials as set out in E.3

Note 2: If the product leaves no solid residue after being dissolved in water it may be described as 'for dissolution'.

Note 3: Where a micro-nutrient is present in a chelated form, the pH range guaranteeing acceptable stability of the chelated fraction shall be stated.

E.1. Fertilizers containing only one micro-nutrient

E.1.1. Boron

>TABLE POSITION>

E.1.2. Cobalt

>TABLE POSITION>

E.1.3. Copper

>TABLE POSITION>

E.1.4 Iron

>TABLE POSITION>

E.1.5. Manganese

>TABLE POSITION>

E.1.6. Molybdenum

>TABLE POSITION>

E.1.7. Zinc

>TABLE POSITION>

E.2. Minimum micro-nutrient content, percentage weight of fertilizer

E.2.1. Solid or fluid mixtures of micro-nutrient

>TABLE POSITION>

Minimum total of micro-nutrient in a solid mixture: 5 % by mass of the fertilizer.

Minimum total of micro-nutrient in a fluid mixture: 2 % by mass of the fertilizer.

E.2.2. EEC fertilizers containing primary and/or secondary nutrient with micro-nutrient applied to the soil

>TABLE POSITION>

E.2.3. EEC fertilizers containing primary and/or secondary nutrient with micro-nutrients for leaf sprays

>TABLE POSITION>

E.3. List of authorised organic chelating and complexing agents for micro-nutrients

Authorised products

E.3.1. Chelating agents

Sodium, potassium or ammonium acid or salts of:

>TABLE POSITION>

E.3.2. Complexing agents

List to be drawn up

ANNEX II Tolerances

The tolerances given in this Annex are negative values in percentage by mass.

The tolerance allowed in respect of the declared nutrient contents in the various types of EC fertilizer are as follows:

1. Inorganic straight primary nutrient fertilizers absolute value in percentage by mass expressed as N, P2O5, K2O, MgO, Cl

1.1. Nitrogenous fertilizers

>TABLE POSITION>

1.2. Phosphatic fertilizers

>TABLE POSITION>

1.3. Potassic fertilizers

>TABLE POSITION>

1.4. Other components

>TABLE POSITION>

2. INORGANIC COMPOUND PRIMARY NUTRIENT FERTILIZERS

2.1. Nutrient elements

>TABLE POSITION>

2.2. Total negative deviations from the declared value

>TABLE POSITION>

3. SECONDARY NUTRIENTS IN FERTILIZERS

The tolerances allowed in respect of the declared calcium, magnesium, sodium and sulphur contents shall be a quarter of the declared contents of these nutrients up to a maximum of 0,9 % in absolute terms for CaO, MgO, Na2O, and SO3, i.e. 0,64 for Ca, 0,55 for Mg, 0,67 for Na and 0,36 for S.

4. MICRO-NUTRIENTS IN FERTILIZERS

The tolerance allowed in respect of the declared micro-nutrient content shall be:

- 0,4 % in absolute terms for a content of more than 2 %,

- one fifth of the declared value for a content not exceeding 2 %.

The tolerance allowed in respect of the declared content for the various forms of nitrogen or the declared solubilities of phosphorus pentoxide is one-tenth of the overall content of the nutrient concerned with a maximum of 2 % by mass, provided that the overall content of that nutrient remains within the limits specified in Annex I and the tolerances specified above.

ANNEX III Technical provisions for Ammonium Nitrate Fertilizers of High Nitrogen Content

1. CHARACTERISTICS OF AND LIMITS FOR STRAIGHT AMMONIUM NITRATE FERTILIZERS OF HIGH NITROGEN CONTENT

1.1. Porosity (oil retention)

The oil retention of the fertilizer, which must first have undergone two thermal cycles of a temperature ranging from 25 to 50 °C and conforming with the provisions of part 2 of section 3. of this Annex, must not exceed 4 % by mass.

1.2. Combustible ingredients

The percentage by mass of combustible material measured as carbon must not exceed 0.2 % for fertilizers having a nitrogen content of at least 31.5 % by mass and must not exceed 0.4 % for fertilizers having a nitrogen content of at least 28 % but less than 31.5 % by mass.

1.3. pH

A solution of 10 g of fertilizer in 100 ml of water must have a pH of at least 4.5.

1.4. Particle size analysis

Not more than 5 % by mass of the fertilizer must pass through a 1 mm mesh sieve and not more than 3 % by mass must pass through a 0.5 mm mesh sieve.

1.5. Chlorine

The maximum chlorine content is set at 0.02 % by mass.

1.6. Heavy metals

Heavy metals should not be added deliberately, and any traces which are incidental to the production process should not exceed the limit fixed by the Committee.

The copper content shall not be higher than 10 mg/kg.

No limits are specified for other heavy metals.

2. DESCRIPTION OF THE TEST OF RESISTANCE TO DETONATION CONCERNING AMMONIUM NITRATE FERTILIZERS OF HIGH NITROGEN CONTENT

The test must be carried out on a representative sample of fertilizer. Before being tested for resistance to detonation, the whole mass of the sample is to be thermally cycled five times complying with the provisions of part 3 in section 3. of this Annex.

The fertilizer must be subjected to the test of resistance to detonation in a horizontal steel tube under the following conditions:

- seamless steel tube,

- Tube length: 1 000 mm at least,

- Nominal external diameter: 114 mm at least,

- Nominal wall thickness: 5 mm at least,

- Booster: the type and mass of the booster chosen should be such as to maximise the detonation pressure applied to the sample in order to determine its susceptibility to the transmission of detonation,

- Test temperature: 15-25 °C,

- Witness lead cylinders for detecting detonation: 50 mm diameter and 100 mm high

placed at 150 mm intervals and supporting the tube horizontally. The test is to be carried out twice. The test is deemed conclusive if in both tests one or more of the supporting lead cylinders is crushed by less than 5 %.

3. METHODS OF CHECKING COMPLIANCE WITH THE LIMITS SPECIFIED IN ANNEXES III-1 and III-2

Method 1 Methods for the application of thermal cycles

1. Scope and field of application

This document defines the procedures for the application of thermal cycles prior to the execution of the oil retention test for straight ammonium nitrate fertilizers of high nitrogen content and of the test on the resistance to detonation for both, straight and compound ammonium nitrate fertilizer of high nitrogen content.

The methods of the closed thermal cycles as described in this section are regarded as simulating sufficiently the conditions to be taken into account within the scope of application of title II, chapter IV, however, these methods may not necessarily simulate all conditions arising during transport and storage;

2. Thermal cycles referred to in Annex III-1

2.1. Field of application

This procedure is for thermal cycling prior to determining the oil retention of the fertilizer.

2.2. Principle and definition

In an Erlenmeyer flask, heat the sample from ambient temperature to 50 °C and maintain at this temperature for a period of two hours (phase at 50 °C). Thereupon cool the sample until a temperature of 25 °C is achieved and maintain at that temperature for two hours (phase at 25 °C). The combination of the successive phases at 50 °C and 25 °C forms one thermal cycle. After being subjected to two thermal cycles, the test sample is held at a temperature of 20 +/- 3 °C for the determination of the oil retention value.

2.3. Apparatus

Normal laboratory apparatus, in particular:

- water baths thermostated at 25 (± 1) and 50 (± 1) °C respectively,

- Erlenmeyer flasks with an individual capacity of 150 ml.

2.4. Procedure

Put each test sample of 70 (± 5) grams into an Erlenmeyer flask which is then sealed with a stopper.

Move each flask every two hours from the 50 °C bath to the 25 °C bath and vice versa.

Maintain the water in each bath at constant temperature and keep in motion by rapid stirring to ensure the water level comes above the level of the sample. Protect the stopper from condensation by a foam rubber cap.

3. Thermal cycles to be used for Annex III-2

3.1. Field of application

This procedure is for thermal cycling prior to the execution of the detonability test.

3.2. Principle and definition

In a watertight box heat the sample from ambient temperature to 50 °C and maintain at this temperature for a period of one hour (phase at 50 °C). Thereupon cool the sample until a temperature of 25 °C is achieved and maintain at that temperature for one hour (phase at 25 °C). The combination of the successive phases at 50 °C and 25 °C forms one thermal cycle. After being subjected to the required number of thermal cycles, the test sample is held at a temperature of 20 +/- 3 °C pending the execution of the detonability test.

3.3. Apparatus

- A water bath, thermostated in a temperature range of 20 to 51 °C with a minimum heating and cooling rate of 10 °C/h, or two water baths, one thermostated at a temperature of 20 °C, the other at 51 °C. The water in the bath(s) is continuously stirred; the volume of the bath should be large enough to guarantee ample circulation of the water.

- A stainless steel box, watertight all around and provided with a thermocouple in the centre. The outside width of the box is 45 (± 2) mm and the wall thickness is 1,5 mm (see Figure 1). The height and length of the box can be chosen to suit the dimensions of the water bath, e.g. length 600 mm, height 400 mm.

3.4. Procedure

Place a quantity of fertilizers sufficient for a single detonation into the box and close the cover. Place the box in the water bath. Heat the water to 51 °C and measure the temperature in the centre of the fertilizer. One hour after the temperature at the centre has reached 50 °C cool the water. One hour after the temperature at the centre has reached 25 °C heat the water to start the second cycle. In the case of two water baths, transfer the box to the other bath after each heating/cooling period.

Figure 1

>REFERENCE TO A GRAPHIC>

Method 2 Determination of oil retention

1. Scope and field of application

This document defines the procedure for the determination of oil retention of straight ammonium nitrate fertilizers of high nitrogen content.

The method is applicable to both prilled and granular fertilizers which do not contain oil-soluble materials.

2. Definition

Oil retention of a fertilizer: the quantity of oil retained by the fertilizer determined under the operating conditions specified, and expressed as a percentage by mass.

3. Principle

Total immersion of the test portion in gas oil for a specified period, followed by the draining away of surplus oil under specified conditions. Measurement of the increase in mass of the test portion.

4. Reagent

Gas oil

Viscosity max.: 5 mPas at 40 °C

Density: 0,8 to 0,85 g/ml at 20 °C

Sulphur content: <= 1,0 % (m/m)

Ash: <= 0,1 % (m/m)

5. Apparatus

Ordinary laboratory apparatus, and:

5.1. Balance, capable of weighing to the nearest 0,01 gram.

5.2. Beakers, of capacity 500 ml.

5.3. Funnel, of plastic materials, preferably with a cylindrical wall at the upper end, diameter approximately 200 mm.

5.4. Test sieve, aperture 0,5 mm, fitting into the funnel (5.3).

Note: The size of the funnel and sieve is such as to ensure that only a few granules lie one above another and the oil is able to drain easily.

5.5. Filter paper, rapid filtering grade, creped, soft, mass 150 g/m2.

5.6. Absorbent tissue (laboratory grade).

6. Procedure

6.1. Two individual determinations are carried out in quick succession on separate portions of the same test sample.

6.2. Remove particles smaller than 0,5 mm using the test sieve (5.4). Weigh to the nearest 0,01 gram approximately 50 grams of the sample into the beaker (5.2). Add sufficient gas oil (section 4) to cover the prills completely and stir carefully to ensure that the surfaces of all the prills are fully wetted. Cover the beaker with a watch glass and leave to stand for one hour at 25 (± 2) °C.

6.3. Filter the entire contents of the beaker through the funnel (5.3) containing the test sieve (5.4). Allow the portion retained by the sieve to remain there for one hour so that most of the excess oil can drain away.

6.4. Lay two sheets of filter paper (5.5) (about 500 ( 500 mm) on top of each other on a smooth surface; fold the four edges of both filter papers upwards to a width of about 40 mm to prevent the prills from rolling away. Place two layers of absorbent tissue (5.6) in the centre of the filter papers. Pour the entire contents of the sieve (5.4) over the absorbent tissues and spread the prills evenly with a soft, flat brush. After two minutes lift one side of the tissues to transfer the prills to the filter papers beneath and spread them evenly over these with the brush. Lay another sheet of filter paper, similarly with its edges turned upward, on the sample and roll the prills between the filter papers with circular movements while exerting a little pressure. Pause after every eight circular movements to lift the opposite edges of the filter papers and return to the centre the prills that have rolled to the periphery. Keep to the following procedure: make four complete circular movements, first clockwise and then anticlockwise. Then roll the prills back to the centre as described above. This procedure to be carried out three times (24 circular movements, edges lifted twice). Carefully insert a new sheet of filter paper between the bottom sheet and the one above it and allow the prills to roll onto the new sheet by lifting the edges of the upper sheet. Cover the prills with a new sheet of filter paper and repeat the same procedure as described above. Immediately after rolling, pour the prills into a tared dish and reweigh to the nearest 0,01 gram to determine the mass of the quantity of gas oil retained.

6.5. Repeating the rolling procedure and reweighing

If the quantity of gas oil retained in the portion is found to be greater than 2,00 grams, place the portion on a fresh set of filter papers and repeat the rolling procedure, lifting the corners in accordance with section 6.4 (two times eight circular movements, lifting once). Then reweigh the portion.

7. Expression of the results

7.1. Method of calculation and formula

The oil retention, from each determination (6.1) expressed as a percentage by mass of the sieved test portion, is given by the equation:

>TABLE POSITION>

where:

m1 is the mass, in grams, of the sieved test portion (6.2),

m2 is the mass, in grams, of the test portion according to section 6.4 or 6.5 respectively as the result of the last weighing.

Take as the result the arithmetic mean of the two individual determinations.

Method 3 Determination of the combustible ingredients

1. Scope and field of application

This document defines the procedure for the determination of the combustible content of straight ammonium nitrate fertilizers of high nitrogen content.

2. Principle

The carbon dioxide produced by inorganic fillers is removed in advance with an acid. The organic compounds are oxidised by means of a chromic acid/sulphuric acid mixture. Carbon dioxide formed is absorbed in a barium hydroxide solution. The precipitate is dissolved in a solution of hydrochloric acid and measured by back-titration with sodium hydroxide solution.

3. Reagents

3.1. Analytical-grade chromium (VI) trioxide Cr2O3;

3.2. Sulphuric acid, 60 % by volume: pour 360 ml of water into a one-litre beaker and carefully add 640 ml of sulphuric acid (density at 20 °C = 1.83 g/ml).

3.3. Silver nitrate: 0,1 mol/l solution.

3.4. Barium hydroxide

Weigh out 15 grams of barium hydroxide [Ba(OH)2. 8H2O], and dissolve completely in hot water. Allow to cool and transfer to a one-litre flask. Fill up to the mark and mix. Filter through a pleated filter paper.

3.5. Hydrochloric acid: 0,1 mol/l standard solution.

3.6. Sodium hydroxide: 0,1 mol/l standard solution.

3.7. Bromophenol blue: solution of 0,4 grams per litre in water.

3.8. Phenolphthalein: solution of 2 grams per litre in 60 % by volume ethanol.

3.9. Soda lime: particle dimensions, about 1,0 to 1,5 mm.

3.10. Demineralised water, freshly boiled to remove carbon dioxide.

4. Apparatus

4.1. Standard laboratory equipment, in particular:

- filter crucible with a plate of sintered glass and a capacity of 15 ml; plate diameter: 20 mm; total height: 50 mm; porosity 4 (pore diameter from 5 to 15 µm),

- 600-ml beaker.

4.2. Compressed nitrogen supply.

4.3. Apparatus made up of the following parts and assembled, if possible, by means of spherical ground joints (see Figure 2).

4.3.1. Absorption tube A about 200 mm long and 30 mm in diameter filled with soda lime (3.9) kept in place by fibreglass plugs.

4.3.2. 500-ml reaction flask B with side arm and a round bottom.

4.3.3. Vigreux fractionating column about 150 mm long (C').

4.3.4. Double-surface condenser C, 200 mm long.

4.3.5. Drechsel bottle D acting as a trap for any excess acid which may distil over.

4.3.6. Ice bath E to cool the Drechsel bottle.

4.3.7. Two absorption vessels F1 and F2, 32 to 35 mm in diameter, the gas distributor of which comprises a 10 mm disc of low-porosity sintered glass.

4.3.8. Suction pump and suction regulating device G comprising a T-shaped glass piece inserted into the circuit, the free arm of which is connected to the fine capillary tube by a short rubber tube fitted with a screw clamp.

Caution: The use of boiling chromic acid solution in an apparatus under reduced pressure is a hazardous operation and requires appropriate precautions.

5. Procedure

5.1. Sample for analysis

Weigh approximately 10 grams of ammonium nitrate to the nearest 0,001 grams.

5.2. Removal of carbonates

Place the sample for analysis in the reaction flask B. Add 100 ml of H2SO4 (3.2). The prills dissolve in about 10 minutes at ambient temperature. Assemble the apparatus as indicated in the diagram: connect one end of the absorption tube (A) to the nitrogen source (4.2) via a non-return flow device containing 5 to 6 mm of mercury and the other end to the feed tube which enters the reaction flask. Place the Vigreux fractionating column (C') and the condenser (C) with cooling water supply in position. Adjust the nitrogen to provide a moderate flow through the solution, bring the solution to boiling point and heat for two minutes. At the end of this time there should be no more effervescence. If effervescence is seen, continue heating for 30 minutes. Allow solution to cool for at least 20 minutes with the nitrogen flowing through it.

Complete assembly of the apparatus as indicated in the diagram by connecting the condenser tube to the Drechsel bottle (D) and the bottle to the absorption vessels F1 and F2. The nitrogen must continue to pass through the solution during the assembly operation. Rapidly introduce 50 ml of barium hydroxide solution (3.4) into each of the absorption vessels (F1 and F2).

Bubble a stream of nitrogen through for about 10 minutes. The solution must remain clear in the absorbers. If this does not happen, the carbonate removal process must be repeated.

5.3. Oxidation and absorption

After withdrawing the nitrogen feed tube, rapidly introduce 20 grams of chromium trioxide (3.1) and 6 ml of silver nitrate solution (3.3) via the side arm of the reaction flask (B). Connect the apparatus to the suction pump and adjust the nitrogen flow so that a steady stream of gas bubbles passes through the sintered-glass absorbers F1 and F2.

Heat the reaction flask (B) until the liquid boils and keep it boiling for one and a half hours [16]. It may be necessary to adjust the suction-regulating valve (G) to control the nitrogen flow since it is possible that the barium carbonate precipitated during the test may block the sintered-glass discs. The operation is satisfactory when the barium hydroxide solution in the absorber F2 remains clear. Otherwise repeat the test. Stop heating and dismantle the apparatus. Wash each of the distributors (3.10) both inside and outside to remove barium hydroxide and collect the washings in the corresponding absorber. Place the distributors one after the other in a 600-ml beaker which will subsequently be used for the determination.

[16] A reaction time of one and a half hours, is sufficient in the case of most of the organic substances in the presence of silver nitrate catalyst.

Rapidly filter under vacuum firstly the contents of absorber F2 and then of absorber F1 using the sintered-glass crucible. Collect the precipitate by rinsing the absorbers with water (3.10) and wash the crucible with 50 ml of the same water. Place the crucible in the 600-ml beaker and add about 100 ml of boiled water (3.10). Introduce 50 ml of boiled water into each of the absorbers and pass nitrogen through the distributors for five minutes. Combine the water with that from the beaker. Repeat the operation once to ensure that the distributors are rinsed thoroughly.

5.4. Measurement of the carbonates originating from organic material

Add five drops of phenolphthalein (3.8) to the contents of the beaker. The solution becomes red in colour. Add hydrochloric acid (3.5) drop by drop until the pink colour just disappears. Stir the solution well in the crucible to check that the pink colour does not reappear. Add five drops of bromphenol blue (3.7) and titrate with hydrochloric acid (3.5) until the solution turns yellow. Add a further 10 ml of hydrochloric acid.

Heat the solution to boiling point and continue boiling for a maximum of one minute. Check carefully that no precipitate remains in the liquid.

Allow to cool and back titrate with the sodium hydroxide solution (3.6).

6. Blank test

Carry out a blank test following the same procedure and using the same quantities of all reagents.

7. Expression of the results

The content of combustible ingredients (C), expressed as carbon, as a percentage by mass of the sample, is given by the formula:

>TABLE POSITION>

where:

E =the mass in grams of the test portion,

V1 = the total volume in ml of 0,1 mol/l hydrochloric acid added after the change in colour of the phenolphthalein,

V2 = the volume in ml of the 0,1 mol/l sodium hydroxide solution used for back titration.

Figure 2

>REFERENCE TO A GRAPHIC>

Method 4 Determination of the pH value

1. Scope and field of application

This document defines the procedure for measuring the pH value of a solution of a straight ammonium nitrate fertilizer of high nitrogen content.

2. Principle

Measurement of the pH of an ammonium nitrate solution by means of a pH meter.

3. Reagents

Distilled or demineralised water, free from carbon dioxide.

3.1. Buffer solution, pH 6,88 at 20 °C

Dissolve 3,40 ± 0,01 grams of potassium dihydrogen orthophosphate (KH2PO4) in approximately 400 ml of water. Then dissolve 3,55 ± 0,01 grams of disodium hydrogen orthophosphate (Na2HPO4) in approximately 400 ml of water. Transfer the two solutions without loss into a 1 000-ml graduated flask, make up to the mark and mix. Keep this solution in an airtight vessel.

3.2. Buffer solution, pH 4,00 at 20 °C

Dissolve 10,21 ± 0,01 grams of potassium hydrogen phthalate (KHC8O4H4) in water, transfer without loss into a 1 000-ml graduated flask, make up to the mark and mix.

Keep this solution in an airtight vessel.

3.3. Commercially available pH standard solutions may be used.

4. Apparatus

pH meter, equipped with glass and calomel electrodes or equivalent, sensitivity 0,05 pH unit.

5. Procedure

5.1. Calibration of the pH meter

Calibrate the pH meter (4) at a temperature of 20 (± 1) °C, using the buffer solutions (3.1), (3.2) or (3.3). Pass a slow stream of nitrogen onto the surface of the solution and maintain this throughout the test.

5.2. Determination

Pour 100,0 ml of water onto 10 (± 0,01) grams of the sample in a 250-ml beaker. Remove the insolubles by filtering, decanting or centrifuging the liquid. Measure the pH value of the clear solution at a temperature of 20 (± 1) °C according to the same procedure as for the calibration of the meter.

6. Expression of the results

Express the result in pH units, to the nearest 0,1 unit, and state the temperature used.

Method 5 Determination of the particle size

1. Scope and field of application

This document defines the procedure for the test sieving of straight ammonium nitrate fertilizers of high nitrogen content.

2. Principle

The test sample is sieved on a nest of three sieves, either by hand or by mechanical means. The mass retained on each sieve is recorded and the percentage of material passing the required sieves are calculated.

3. Apparatus

3.1. 200-mm-diameter woven-wire test sieves with apertures of 2,0 mm, 1,0 mm and 0,5 mm respectively of standard ranges. One lid and one receiver for these sieves.

3.2. Balance to weigh to 0,1 gram.

3.3. Mechanical sieve shaker (if available) capable of imparting both vertical and horizontal motion to the test sample.

4. Procedure

4.1. The sample is divided representatively into portions of approximately 100 grams.

4.2. Weigh one of these portions to the nearest 0,1 gram.

4.3. Arrange the nest of sieves in ascending order; receiver, 0,5 mm, 1 mm, 2 mm and place the weighed test portion on the top sieve. Fit the lid to the top of the nest of sieves.

4.4. Shake by hand or machine, imparting both a vertical and horizontal motion and if by hand, tapping occasionally. Continue this process for 10 minutes or until the quantity passing through each sieve in one minute is less than 0,1 gram.

4.5. Remove the sieves from the nest in turn and collect the material retained, brush gently from the reverse side with a soft brush, if necessary.

4.6. Weigh the material retained on each sieve and that collected in the receiver, to the nearest 0,1 gram.

5. Evaluation of the results

5.1. Convert the fraction masses to a percentage of the total of the fraction masses (not of the original charge).

Calculate the percentage in the receiver (i.e. < 0,5 mm): A %

Calculate the percentage retained on the 0,5 mm sieve: B %

Calculate the percentage passing 1,0 mm, i.e. (A + B) %

The sum of the fraction masses should be within 2 % of the initial mass taken.

5.2. At least two separate analyses should be carried out and the individual results for A should not differ by more than 1,0 % absolute and for B by more than 1,5 % absolute. Repeat the test if this is not the case.

6. Expression of the results

Report the mean of the two values obtained for A on the one hand and for A+B on the other.

Method 6 Determination of the chlorine content (as chloride ion)

1. Scope and field of application

This document defines the procedure for the determination of the chlorine content (as chloride ion) of straight ammonium nitrate fertilizers with a high nitrogen content.

2. Principle

Chloride ions dissolved in water are determined by potentiometric titration with silver nitrate in an acidic medium.

3. Reagents

Distilled or demineralised water, free from chloride ions.

3.1. Acetone AR.

3.2. Concentrated nitric acid (density at 20 °C = 1,40 g/ml)

3.3. Silver nitrate 0,1 mol/l standard solution. Store this solution in a brown glass bottle.

3.4. Silver nitrate 0,004 mol/l standard solution - prepare this solution at the time of use.

3.5. Potassium chloride 0,1 mol/l standard reference solution. Weigh, to the nearest 0,1 mg, 3,7276 grams of analytical-grade potassium chloride, previously dried for one hour in an oven at 130 °C and cooled in a desiccator to ambient temperature. Dissolve in a little water, transfer the solution without loss into a 500-ml standard flask, dilute to the mark and mix.

3.6. Potassium chloride, 0,004 mol/l standard reference solution - prepare this solution at the time of use.

4. Apparatus

4.1. Potentiometer with silver indicating electrode and calomel reference electrode, sensitivity 2 mV, covering the range - 500 to + 500 mV.

4.2. Bridge, containing a saturated potassium nitrate solution, connected to the calomel electrode (4.1), fitted at the ends with porous plugs.

4.3. Magnetic stirrer, with a Teflon-coated rod.

4.4. Microburette with fine-pointed tip, graduated in 0,01 ml divisions.

5. Procedure

5.1. Standardisation of the silver nitrate solution

Take 5,00 ml and 10,00 ml of the standard reference potassium chloride solution (3.6) and place in two low-form beakers of convenient capacity (for example 250 ml). Carry out the following titration of the contents of each beaker.

Add 5 ml of the nitric acid solution (3.2), 120 ml of the acetone (3.1) and sufficient water to bring the total volume to about 150 ml. Place the rod of the magnetic stirrer (4.3) in the beaker and set the stirrer in motion. Immerse the silver electrode (4.1) and the free end of the bridge (4.2) in the solution. Connect the electrodes to the potentiometer (4.1) and, after verifying the zero of the apparatus, note the value of the starting potential.

Titrate, using the microburette (4.4), adding initially 4 or 9 ml respectively of the silver nitrate solution corresponding to the standard reference potassium chloride solution used. Continue the addition in 0,1 ml portions for the 0,004 mol/l solutions and in 0,05 ml portions for the 0,1 mol/l solutions. After each addition, await the stabilisation of the potential.

Record the volumes added and the corresponding values of the potential in the first two columns of a table.

In a third column of the table, record the successive increments ((1E) of the potential E. In a fourth column, record the differences ((2E) positive or negative, between the potential increments ((1E). The end of the titration corresponds to the addition of the 0,1 or 0,05 ml portion (V1) of the silver nitrate solution which gives the maximum value of (1E.

In order to calculate the exact volume (Veq) of the silver nitrate solution corresponding to the end of the reaction, use the formula:

>TABLE POSITION>

where:

V0 is the total volume, in ml, of the silver nitrate solution immediately lower than the volume which gives the maximum increment of (1E,

V1 is the volume, in ml, of the last portion of the silver nitrate solution added (0,1 or 0,05 ml),

b is the last positive value of (2E,

B is the sum of the absolute values of the last positive values of (2E and the first negative value of (2E (see example in Table 1).

5.2. Blank test

Carry out a blank test and take account thereof when calculating the final result.

The result V4 of the blank test on the reagents is given, in ml, by the formula:

V4 = 2V3 - V2

where:

V2 is the value, in ml, of the exact volume (Veq) of the silver nitrate solution corresponding to the titration of 10 ml of the potassium chloride standard reference solution used,

V3 is the value, in ml, of the exact volume (Veq) of the silver nitrate solution corresponding to the titration of 5 ml of the potassium chloride standard reference solution used.

5.3. Check test

The blank test can at the same time serves as a check that the apparatus is functioning satisfactorily and that the test procedure is being implemented correctly.

5.4. Determination

Take a portion of sample in the range 10 to 20 grams and weigh to the nearest 0,01 gram. Transfer quantitatively to a 250-ml beaker. Add 20 ml of water, 5 ml of nitric acid solution (3.2), 120 ml of acetone (3.1) and sufficient water to bring the total volume to about 150 ml.

Place the rod of the magnetic stirrer (4.3) in the beaker, place the beaker on the stirrer and set the stirrer in motion. Immerse the silver electrode (4.1) and the free end of the bridge (4.2) in the solution, connect the electrodes to the potentiometer (4.1) and, after having verified the zero of the apparatus, note the value of the starting potential.

Titrate with the silver nitrate solution, by additions from the microburette (4.4) in increments of 0,1 ml. After each addition, await the stabilisation of the potential.

Continue the titration as specified in 5.1, starting from the fourth paragraph: "Record the volumes added and the corresponding values of the potential in the first two columns of a table ...".

6. Expression of the results

Express the result of the analysis as the percentage of chlorine contained in the sample as received for analysis. Calculate the percentage of chlorine (Cl) content from the formula:

>TABLE POSITION>

where:

T is the concentration of silver nitrate solution used, in mol/l

V4 is the result, in ml, of the blank test (5.2),

V5 is the value, in ml, of Veq corresponding to the determination (5.4),

M is the mass, in grams, of the test portion.

Table 1 Example

>TABLE POSITION>

Method 7 Determination of copper

1. Scope and field of application

This document defines the procedure for the determination of copper content of straight ammonium nitrate fertilizers of high nitrogen content.

2. Principle

The sample is dissolved in dilute hydrochloric acid and the copper is determined by atomic absorption spectrophotometry.

3. Reagents

3.1. Hydrochloric acid (density at 20 °C = 1,18 g/ml).

3.2. Hydrochloric acid, 6 mol/l solution.

3.3. Hydrochloric acid 0,5 mol/l solution.

3.4. Ammonium nitrate.

3.5. Hydrogen peroxide, 30 % w/v

3.6. Copper solution [17] (stock): weigh, to the nearest 0,001 gram, 1 gram of pure copper, dissolve in 25 ml 6 mol/l hydrochloric acid solution (3.2), add 5 ml of hydrogen peroxide (3.5) in portions and dilute to 1 litre with water. 1 ml of this solution contains 1 000 µg of copper (Cu).

[17] Commercially available standard copper solution may be used.

3.6.1. Copper solution (dilute): dilute 10 ml of stock solution (3.6) to 100 ml with water and then dilute 10 ml of the resulting solution, to 100 ml with water, 1 ml of the final dilution contains 10 µg of copper (Cu).

Prepare this solution at the time of use.

4. Apparatus

Atomic absorption spectrophotometer with a copper lamp (324,8 nm).

5. Procedure

5.1. Preparation of the solution for analysis

Weigh, to the nearest 0,001 gram, 25 grams of the sample, place it in a 400-ml beaker, add carefully 20 ml of hydrochloric acid (3.1) (there may be a vigorous reaction due to carbon dioxide formation). Add more hydrochloric acid, if necessary. When effervescence has stopped, evaporate to dryness on a steam bath, stirring occasionally with a glass rod. Add 15 ml 6 mol/l hydrochloric acid solution (3.2) and 120 ml of water. Stir with the glass rod, which should be left in the beaker, and cover the beaker with a watch glass. Boil the solution gently until dissolution is complete and then cool.

Transfer the solution quantitatively into a 250-ml graduated flask, by washing the beaker with 5 ml 6 mol/l hydrochloric acid (3.2), and twice with 5 ml of boiling water, make up to the mark with 0,5 mol/l hydrochloric acid (3.3) and mix carefully.

Filter through a copper-free filter paper [18], discarding the first 50 ml.

[18] Whatman 541 or equivalent.

5.2. Blank solution

Prepare a blank solution from which only the sample has been omitted and allow for this in the calculation of the final results.

5.3. Determination

5.3.1. Preparation of sample and blank test solutions

Dilute the sample solution (5.1) and the blank test solution (5.2) with 0,5 mol/l hydrochloric acid solution (3.3) to a concentration of copper within the optimal measuring range of the spectrophotometer. Normally no dilution is needed.

5.3.2. Preparation of the calibration solutions

By diluting the standard solution (3.6.1) with 0,5 mol/l hydrochloric acid solution (3.3), prepare at least five standard solutions corresponding to the optimal measuring range of the spectrophotometer (0 to 5,0 mg/l Cu). Before making up to the mark, add to every solution ammonium nitrate (3.4) to give concentration of 100 mg per ml.

5.4. Measurement

Set up the spectrophotometer (4) at a wavelength of 324,8 nm. Use an oxidising air-acetylene flame. Spray successively, in triplicate, the calibration solution (5.3.2), the sample solution and the blank solution (5.3.1), washing the instrument through with distilled water between each spraying. Plot the calibration curve using the mean absorbances of every standard used as the ordinates and the corresponding concentrations of copper in µg/ml as the abscissae.

Determine the concentration of copper in the final sample and blank solutions by reference to the calibration curve.

6. Expression of the results

Calculate the copper content of the sample taking into account the mass of the test sample, the dilutions carried out in the course of the analysis and the value of the blank. Express the result as mg Cu/kg.

4. DETERMINATION OF RESISTANCE TO DETONATION

4.1. Scope and field of application

This document defines the procedure for the determination or resistance to detonation of ammonium nitrate fertilizers of high nitrogen content.

4.2. Principle

The test sample is confined in a steel tube and subjected to detonation shock from an explosive booster charge. Propagation of the detonation is determined from the degree of crushing of lead cylinders on which the tube rests horizontally during the test.

4.3. Materials

4.3.1. Plastic explosive containing 83 to 86 % penthrite

Density: 1 500 to 1 600 kg/m3

Detonation velocity: 7 300 to 7 700 m/s

Mass: 500 ± 1 gram.

4.3.2. Seven lengths of flexible detonating cord with non-metallic sleeve

Filling mass: 11 to 13 g/m

Length of each cord: 400 ± 2 mm.

4.3.3. Compressed pellet of secondary explosive, recessed to receive detonator

Explosive: hexogen/wax 95/5 or tetryl or similar secondary explosive, with or without added graphite.

Density: 1 500 to 1 600 kg/m3

Diameter: 19 to 21 mm

Height: 19 to 23 mm

Central recess to receive detonator: diameter 7 to 7,3 mm, depth 12 mm.

4.3.4. Seamless steel tube as specified in ISO 65 - 1981 - Heavy Series, with nominal dimensions DN 100 (4'')

Outside diameter: 113,1 to 115,0 mm

Wall thickness: 5,0 to 6,5 mm

Length: 1 005 (± 2) mm.

4.3.5. Bottom place

Material: steel of good weldable quality

Dimensions: 160 ( 160 mm

Thickness: 5 to 6 mm.

4.3.6. Six lead cylinders

Diameter: 50 (± 1) mm

Height: 100 to 101 mm

Materials: soft lead, at least 99,5 % purity.

4.3.7. Steel block

Length: at least 1 000 mm

Width: at least 150 mm

Height: at least 150 mm

Mass: at least 300 kg if there is no firm base for the steel block.

4.3.8. Plastic or cardboard cylinder for booster charge

Wall thickness: 1,5 to 2,5 mm

Diameter: 92 to 96 mm

Height: 64 to 67 mm.

4.3.9. Detonator (electric or non-electric) with initiation force 8 to 10

4.3.10. Wooden disc

Diameter: 92 to 96 mm. Diameter to be matched to the internal diameter of the plastic or cardboard cylinder (4.3.8)

Thickness: 20 mm.

4.3.11. Wooden rod of same dimensions as detonator (4.3.9)

4.3.12. Dressmaking pins (maximum length 20 mm)

4.4. Procedure

4.4.1. Preparation of booster charge for insertion into steel tube

There are two methods of initiation of the explosive in the booster charge, depending on the availability of equipment.

4.4.1.1. Seven-point simultaneous initiation

The booster charge prepared for use is shown in Figure 1.

4.4.1.1.1.Drill holes in the wooden disc (4.3.10) parallel to the axis of the disc through the centre and through six points symmetrically distributed around a concentric circle 55 mm in diameter. The diameter of the holes must be 6 to 7 mm (see Section A-B in Figure 1), depending on the diameter of the detonating cord used (4.3.2).

4.4.1.1.2.Cut seven lengths of flexible detonating cord (4.3.2) each 400 mm long, avoiding any loss of explosive at each end by making a clean cut and immediately sealing the end with adhesive. Push each of the seven lengths through the seven holes in the wooden disc (4.3.10) until their ends project a few cm on the other side of the disc. Then insert a small dressmaking pin (4.3.12) transversally into the textile sleeve of each length of cord 5 to 6 mm from the end and apply adhesive around the outside of the lengths of cord in a band 2 cm wide adjacent to the pin. Finally, pull the long piece of each cord to bring the pin into contact with the wooden disc.

4.4.1.1.3.Shape the plastic explosive (4.3.1) to form a cylinder 92 to 96 mm in diameter, depending on the diameter of the cylinder (4.3.8). Stand this cylinder upright on a level surface and insert the shaped explosive. Then insert the wooden disc [19] carrying the seven lengths of detonating cord into the top of the cylinder and press it down onto the explosive. Adjust the height of the cylinder (64 to 67 mm) so that its top edge does not extend beyond the level of the wood. Finally, fix the cylinder to the wooden disc for instance with staples or small nails, around its entire circumference.

[19] The diameter of the disc must always correspond to the inside diameter of the cylinder.

4.4.1.1.4.Group the free ends of the seven lengths of detonating cord around the circumference of the wooden rod (4.3.11) so that their ends are all level in a plane perpendicular to the rod. Secure them in a bundle around the rod by means of adhesive tape [20].

[20] NB: When the six peripheral lengths of cord are taut after assembly, the central cord must remain slightly slack.

4.4.1.2. Central initiation by a compressed pellet

The booster charge prepared for use is shown in Figure 2.

4.4.1.2.1.Preparing a compressed pellet

Taking the necessary safety precautions, place 10 grams of a secondary explosive (4.3.3) in a mould with an inside diameter of 19 to 21 mm and compress to the correct shape and density.

(The ratio of diameter: height should be roughly 1:1).

In the centre of the bottom of the mould there is a peg, 12 mm in height and 7,0 to 7,3 mm in diameter (depending on the diameter of the detonator used), which forms a cylindrical recess in the compressed cartridge for subsequent insertion of the detonator.

4.4.1.2.2.Preparing the booster charge

Place the explosive (4.3.1) into the cylinder (4.3.8) standing upright on a level surface, then press it down with a wooden die to give the explosive a cylindrical shape with a central recess. Insert the compressed pellet into this recess. Cover the cylindrically shaped explosive containing the compressed pellet with a wooden disc (4.3.10) having a central hole 7,0 to 7,3 mm in diameter for insertion of a detonator. Fix the wooden disc and the cylinder together with a cross of adhesive tape. Ensure that the hole drilled in the disc and the recess in the compressed pellet are coaxial by inserting the wooden rod (4.3.11).

4.4.2. Preparing steel tubes for the detonation tests

At one end of the steel tube (4.3.4), drill two diametrically opposed holes 4 mm in diameter perpendicularly through the side wall at a distance of 4 mm from the edge.

Butt weld the bottom plate (4.3.5) to the opposite end of the tube, completely filling the right angle between the bottom place and the wall of the tube with weld metal around the entire circumference of the tube.

4.4.3. Filling and charging the steel tube

See Figures 1 and 2.

4.4.3.1. The test sample, the steel tube and the booster charge must be conditioned to temperatures of 20 (± 5) °C. 16 to 18 kg of the test sample are needed for two detonation tests.

4.4.3.2. Place the tube upright with its square bottom place resting on a firm, flat surface, preferably concrete. Fill the tube to about one-third of its height with the test sample and drop it 10 cm vertically onto the floor five times to compact the prills or granules as densely as possible in the tube. To accelerate compaction, vibrate the tube by striking the side wall with a 750 to 1 000-gram hammer between drops for a total of 10 times.

Repeat this charging method with another portion of the test sample. Finally, a further addition shall be made such that, after compaction by raising and dropping the tube 10 times and a total of 20 intermittent hammer blows, the charge fills the tube to a distance of 70 mm from its orifice.

The filling height of the sample must be adjusted in the steel tube so that the booster charge (4.4.1.1 or 4.4.1.2) to be inserted later will be in close contact with the sample over its entire surface.

4.4.3.3. Insert the booster charge into the tube so that it is in contact with the sample; the top surface of the wooden disc must be 6 mm below the end of the tube. Ensure essential close contact between explosive and test sample by adding or removing small quantities of sample. As shown in Figures 1 and 2, split pins should be inserted through the holes near the open end of the tube and their legs opened flat against the tube.

4.4.4. Positioning of the steel tube and lead cylinders (see figure 3)

4.4.4.1. Number the bases of the lead cylinders (4.3.6) 1 to 6. Make six marks 150 mm apart on the centre line of a steel block (4.3.7) lying on a horizontal base, with the first mark at least 75 mm from the edge of the block. Place a lead cylinder upright on each of these marks, with the base of each cylinder centred on its mark.

4.4.4.2. Lay the steel tube prepared according to 4.4.3 horizontally on the lead cylinders so that the axis of the tube is parallel to the centre line of the steel block and the welded end of the tube extends 50 mm beyond lead cylinder N° 6. To prevent the tube from rolling, insert small wooden wedges between the tops of the lead cylinders and the tube wall (one on each side) or place a cross of wood between the tube and the steel block.

Note

Make sure that the tube is in contact with all six lead cylinders; a slight curvature of the tube surface can be compensated for by rotating the tube about its longitudinal axis; if any of the lead cylinders is too tall, tap the cylinder in question carefully with a hammer until it is the required height.

4.4.5. Preparation for detonation

4.4.5.1. Set up the apparatus according to the 4.4.4 in a bunker or suitably prepared underground site (e.g. mine or tunnel). Ensure that the temperature of the steel tube is kept at 20 (± 5 °C before detonation.

Note

Should such firing sites not be available, the work can, if necessary, be done in a concrete-lined pit covered over with wooden beams. Detonation can cause steel fragments to be projected with high kinetic energy, therefore, firing must be carried out at a suitable distance from dwellings or thoroughfares.

4.4.5.2. If the booster charge with seven-point initiation is used, ensure that the detonation cords are stretched out as described in the footnote to 4.4.1.1.4 and arranged as horizontally as possible.

4.4.5.3. Finally, remove the wooden rod and replace with the detonator. Do not carry out firing until the danger zone has been evacuated and the test personnel have taken cover.

4.4.5.4. Detonate the explosive.

4.4.6. Allow sufficient time for the fumes (gaseous and sometimes toxic decomposition products such as nitrous gases) to disperse, then collect the lead cylinders and measure their heights with a Vernier caliper

Record for each of the marked lead cylinders, the degree of crushing expressed as a percentage of the original height of 100 mm. If the cylinders are crushed obliquely, record the highest and the lowest values and calculate the average.

4.4.7. A probe for continuous measurement of the detonation velocity can be used; the probe should be inserted longitudinally to the axis of the tube or along its side wall

4.4.8. Two detonation tests per sample are to be carried out

4.5. Test report

Values for the following parameters are to be given in the test report for each of the detonation tests:

- the values actually measures for the outside diameter of the steel tube and for the wall thickness,

- the Brinell hardness of the steel tube,

- the temperature of the tube and the sample shortly before firing,

- the packing density (kg/m3) of the sample in the steel tube,

- the height of each lead cylinder after firing, specifying the corresponding cylinder number,

- method of initiation employed for the booster charge.

4.5.1. Evaluation of test results

If, in each firing, the crushing of at least one lead cylinder is less than 5 % , the test shall be considered conclusive and the sample in conformity with the requirements of Annex III.2.

Figure 1

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Figure 2

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Figure 3

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ANNEX IV Methods of Sampling and Analysis

A. METHOD OF SAMPLING FOR THE CONTROL OF FERTILIZERS

INTRODUCTION

Correct sampling is a difficult operation which requires the greatest of care. The need to obtain a sufficiently representative sample for the official testing of fertilizers cannot, therefore, be stressed too much.

The sampling Method described below must be applied with strict accuracy by specialists with experience of the conventional sampling procedure.

1. PURPOSE AND SCOPE

Samples intended for the official control of fertilizers, for quality and composition, shall be taken according to the methods described below. Samples thus obtained shall be considered as representative of the sampled portions.

2. SAMPLING OFFICERS

The samples shall be taken by specialist officers authorized for that purpose by the Member States.

3. DEFINITIONS

Sampled portion: A quantity of product constituting a unit, and having characteristics presumed to be uniform.

Incremental sample: A quantity taken from one point in the sampled portion.

Aggregate sample: An aggregate of incremental samples taken from the same sampled portion.

Reduced sample: A representative part of the aggregate sample, obtained from the latter by a process of reduction.

Final sample: A representative part of the reduced sample.

4. APPARATUS

4.1. The sampling apparatus must be made of materials which cannot affect the characteristics of the products to be sampled. Such apparatus may be officially approved by the Member States.

4.2. Apparatus recommended for the sampling of solid fertilizers

4.2.1. Manual sampling

4.2.1.1. Flat-bottomed shovel with vertical sides.

4.2.1.2. Sampling spear with a long split or compartments. The dimensions of the sampling spear must be appropriate to the characteristics of the sampled portion (depth of container, dimensions of sack, etc.) and to the particle size of the fertilizer.

4.2.2. Mechanical sampling

Approved mechanical apparatus may be used for the sampling of moving fertilizers.

4.2.3. Divider

Apparatus designed to divide the sample into equal parts may be used for taking incremental samples and for the preparation of reduced and final samples.

4.3. Apparatus recommended for the sampling of fluid fertilizers

4.3.1. Manual sampling

Open tube, probe, bottle or another appropriate equipment able to take samples at random from the sampled portion.

4.3.2. Mechanical sampling

Approved mechanical apparatus may be used for sampling of moving fluid fertilizers.

5. QUANTITATIVE REQUIREMENTS

5.1. Sampled portion

The size of the sampled portion must be such that each of its constituent parts can be sampled.

5.2. Incremental samples

5.2.1. Loose solid fertilizers or fluid fertilizers in containers exceeding 100 kg

5.2.1.1. Sampled portions not exceeding 2.5 tonnes:

Minimum number of incremental samples: seven

5.2.1.2. Sampled portions exceeding 2.5 tonnes and up to 80 tonnes:

>TABLE POSITION>

5.2.1.3. Sampled portions exceeding 80 tonnes:

Minimum number of incremental samples: 40

5.2.2. Packaged solid fertilizers or fluid fertilizers in containers (= packages each not exceeding 100 kg)

5.2.2.1. Packages of more than 1 kg

5.2.2.1.1.Sampled portions of less than five packages:

Minimum number of packages to be sampled [21]: all packages.

[21] For packages whose contents do not exceed 1 kg, an incremental sample shall be the contents of one original package.

5.2.2.1.2.Sampled portions of five to 16 packages:

Minimum number of packages to be sampled [22]: four.

[22] See note 2.

5.2.2.1.3.Sampled portions of 17 to 400 packages:

>TABLE POSITION>

5.2.2.1.4.Sampled portions exceeding 400 packages:

Minimum number of packages to be sampled [23]: 20.

[23] See note 2.

5.2.2.2. Packages not exceeding 1 kg:

Minimum number of packages to be sampled [24]: four.

[24] See note 2.

5.3. Aggregate sample

A single aggregate sample per sampled portion is required. The total mass of the incremental samples making up the aggregate sample shall be not less than the following:

5.3.1. Loose solid fertilizers or fluid fertilizers in containers exceeding 100 kg: 4 kg.

5.3.2. Packaged solid fertilizers or fluid fertilizers in containers (= packages) each not exceeding 100 kg

5.3.2.1. Packages of more than 1 kg: 4 kg

5.3.2.2. Packages not exceeding 1 kg: mass of the contents of four original packages.

5.3.3. Ammonium nitrate fertilizer sample for tests according to Annex III.2: 75 kg

5.4. Final samples

The aggregate sample gives the final samples on reduction when necessary. Analysis of at least one final sample is required. The mass of the sample for analysis shall not be less than 500 g.

5.4.1. Solid and fluid fertilizers

5.4.2. Ammonium nitrate fertilizer sample for tests

The aggregate sample gives the final sample for tests on reduction when necessary.

5.4.2.1. Minimum final sample mass for Annex III.1 tests: 1 kg

5.4.2.2. Minimum final sample mass for Annex III.2 tests: 25 kg

6. INSTRUCTIONS FOR TAKING, PREPARING AND PACKAGING THE SAMPLES

6.1. General

The samples must be taken and prepared as quickly as possible bearing in mind the precautions necessary to ensure that they remain representative of the fertilizer sampled. Instruments and also surfaces and containers intended to receive samples must be clean and dry.

In the case of fluid fertilizers, if possible the sampled portion should be mixed prior to sampling.

6.2. Incremental samples

Incremental samples must be taken at random throughout the whole sampled portion and they must be of approximately equal sizes.

6.2.1. Loose solid fertilizers or fluid fertilizers in containers exceeding 100 kg

An imaginary division shall be made of the sampled portion into a number of approximately equal parts. A number of parts corresponding to the number of incremental samples required in accordance with 5.2 shall be selected at random and at least one sample taken from each of these parts. Where it is not possible to comply with the requirements of 5.1 when sampling bulk fertilizers or fluid fertilizers in containers exceeding 100 kg the sampling should be carried out when the sampled portion is being moved (loading or unloading). In this case samples shall be taken from the randomly selected notional parts as defined above while these are being moved.

6.2.2. Packaged solid fertilizers or fluid fertilizers in containers (= packages) each not exceeding 100 kg

Having selected the required number of packages for sampling as indicated in 5.2, part of the contents of each package shall be removed. Where necessary, the samples shall be taken after emptying the packages separately.

6.3. Preparation of aggregate sample

The incremental samples shall be mixed to form a single aggregate sample.

6.4. Preparation of the final sample

The material in the aggregate sample shall be carefully mixed [25].

[25] Any lumps shall be broken up (if necessary by separating them out and returning them to the sample).

If necessary the aggregate sample should first be reduced to at least 2 kg (reduced sample) either by using a mechanical divider or by the quartering method.

At least three final samples shall then be prepared, of approximately the same amount and conforming to the quantitative requirements of 5.4. Each sample shall be put into an appropriate air tight container. All necessary precautions shall be taken to avoid any change in the characteristics of the sample.

For the tests of Annex III, sections 1 and 2, the final samples shall be kept at a temperature between 0 °C and 25 °C.

7. PACKAGING OF FINAL SAMPLES

The containers or packages shall be scaled and labelled (the total label must be incorporated in the seal) in such a manner that they cannot be opened without damaging the seal.

8. SAMPLING RECORD

A record must be kept of each sampling, permitting each sampled portion to be identified unambiguously.

9. DESTINATION OF SAMPLES

For each sample portion at least one final sample shall be sent as quickly as possible to an authorized analytical laboratory or to the test institution, together with the information necessary for the analysis or the test.

B. METHODS FOR THE ANALYSIS OF FERTILIZERS

(See table of contents p 2.)

GENERAL OBSERVATIONS

Laboratory equipment

In the descriptions of the methods, general laboratory equipment has not been precisely defined, except that the sizes of flasks and pipettes are given. In all cases laboratory apparatus must be well cleaned, particularly when small quantities of elements are to be determined.

Control tests

Before analysis it is necessary to ensure that all apparatus functions well and that the analytical technique is carried out correctly, using where appropriate chemical compounds of known composition (e.g. ammonium sulphate, mono potassium phosphate, etc.). Nevertheless, the results from analyzed fertilizers can indicate wrong chemical composition if the analytical technique is not rigorously followed. On the other hand, a certain number of determinations are empirical and are relative to products of complex chemical composition. It is recommended that where available, laboratories should make use of standard reference fertilizers of well defined composition.

GENERAL PROVISIONS RELATING TO METHODS OF ANALYZING FERTILIZERS

1. Reagents

Unless otherwise specified in the Method of analysis, all of the reagents must be analysis-pur (a.p.). Where micro-nutrients are to be analyzed the purity of the reagents must be checked by means of a blank test. Depending upon the result obtained, it might be necessary to conduct a further purification.

2. Water

Where dissolution, dilution, rinsing or washing operations referred to in the methods of analysis do not specify the nature of solvents or diluents the use of water is implied. Normally, the water will have to be demineralized or distilled. In these specific instances, as mentioned in the Method of analysis, that water will have to be subjected to specific purification processes.

3. Laboratory equipment

In view of the equipment normally used in inspection laboratories, the apparatus described in the methods of analysis is restricted to special instruments and apparatus or to such demanded by any specific requirements. This equipment must be perfectly clean, above all where small quantities are to be determined. The laboratory will have to ensure the accuracy of any graduated glassware used by referring to appropriate metrological standards.

Method 1 PREPARATION OF THE SAMPLE FOR ANALYSIS

1. SCOPE

This document defines the procedure for the preparation of the sample for analysis, taken from the final sample.

2. PRINCIPLE

The preparation of a final sample received at the laboratory is a series of operations, usually sieving, grinding and mixing, carried out in such a way that:

- on the one hand, the smallest amount weighed out laid down by the methods of analysis is representative of the laboratory sample,

- on the other hand, the fineness of the fertilizer cannot have been changed by the preparation to the extent that its solubility in the various extraction reagents is appreciably affected.

3. APPARATUS

Sample divider (optional).

Sieves with apertus of 0.2 and 0.5 mm.

250-ml flasks, stoppered.

Porcelain pestle and mortar or grinder.

4. CHOICE OF TREATMENT TO BE USED

Preliminary remark

If the product is suitable, only a representative part of the final sample need be kept.

4.1. Final samples which must not be ground

Calcium nitrate, calcium magnesium nitrate, sodium nitrate, Chile nitrate, calcium cyanamide, nitrogenous calcium cyanamide, ammonium sulphate, ammonium nitrates of over 30 % N, urea, basic slag, natural phosphate rendered partially soluble, precipitated dihydrated dicalcium phosphate, calcined phosphate, aluminium calcium phosphate, soft ground rock phosphate.

4.2. Final samples which must be divided and part of which must be ground

These are products in respect of which certain determinations are carried out without previous grinding (fineness of grinding for example) and other determinations after grinding. They include all compound fertilizers containing the following phosphate ingredients: basic slag, aluminium calcium phosphate, calcined phosphate, soft ground rock phosphate and natural phosphate rendered partially soluble. To that end, divide the final sample into two parts, which are as identical as possible, using a sample divider or by quartering.

4.3. Final samples in respect of which all determinations are carried out on a ground product

Only a representative part of the final sample need be ground. These are all the other fertilizers on the list which are not to be found under 4.1 and 4.2.

5. METHOD

The part of the final sample referred to under 4.2 and 4.3 is sieved rapidly through a sieve with apertures of 0.5 mm. The residue is ground roughly so as to obtain a product in which there is a minimum of fine particles, and it is then sieved. The grinding must be done in conditions such that the substance is not appreciably heated. The operation is repeated as many times as is necessary until there is no residue, and it must be effected as quickly as possible in order to prevent any gain or loss of constituents (water, ammonia). The whole ground and sieved product is placed in a clean flask which can be stoppered.

Before any weighing is carried out for the analysis, the whole sample must be thoroughly mixed.

6. SPECIAL CASES

a) Fertilizers comprising a blend of several categories of crystals In this case, separation frequently occurs. It is therefore absolutely essential to crush and pass the sample through a sieve with apertures of 0.200 mm. For example: mixtures of ammonium phosphate and potassium nitrate. The grinding of the whole of the final sample is recommended in the case of these products.

b) Residue which is difficult to grind and does not contain fertilizing substances Weigh the residue and take account of its mass when calculating the final result.

c) Products which decompose on heating Grinding must be carried out in such a way as to avoid any heating. It is preferable in this case to use a mortar for grinding. For example: compound fertilizers containing calcium cyanamide and urea.

d) Products which are abnormally moist or made into a paste by grinding To ensure homogeneity, a sieve is to be chosen which has the smallest apertures compatible with the destruction of lumps by hand or with the pestle. This may be the case of mixtures, certain ingredients of which contain water of crystallization.

Methods 2 NITROGEN

Method 2.1 DETERMINATION OF AMMONIACAL NITROGEN

1. SCOPE

This document defines the procedure for the determination of the ammoniacal nitrogen.

2. FIELD OF APPLICATION

All nitrogenous fertilizers, including compound fertilizers, in which nitrogen is found exclusively either in the form of ammonium salts, or ammonium salts together with nitrates.

It is not applicable to fertilizers containing urea, cyanamide or other organic nitrogenous compounds.

3. PRINCIPLE

Displacement of ammonia by means of an excess of sodium hydroxide; distillation; determining the yield of ammonia in a given volume of a standard sulphuric acid and titration of the excess acid by means of a standard solution of sodium or potassium hydroxide.

4. REAGENTS

Distilled or demineralized water, free from carbon dioxide and all nitrogenous compounds.

4.1. Diluted hydrochloric acid: one volume of HCl (d20 = 1.18 g /ml) plus one volume of water

>TABLE POSITION>

4.8. Sodium hydroxide, approximately 30 % NaOH (d20 = 1.33 g/ml), ammonia free

4.9. Indicator solutions

4.9.1. Mixed indicator

Solution A: Dissolve 1 g of methyl red in 37 ml of sodium hydroxide solution 0.1 mol/l and make up to one litre with water.

Solution B: Dissolve 1 g of methylene blue in water and make up to one litre.

Mix one volume of A with two volumes of B.

This indicator is violet in acid solution, grey in neutral solution and green in alkaline solution. Use 0.5 ml (10 drops) of this indicator solution.

4.9.2. Methyl red indicator solution

Dissolve 0.1 g of methyl red in 50 ml of 95 % ethanol. Make up to 100 ml with water and filter if necessary. This indicator may be used (four to five drops) instead of the preceding one.

4.10. Anti-bump granules of pumice stone, washed in hydrochloric acid and calcined

4.11. Ammonium sulphate for analysis

5. APPARATUS

5.1. Distillation apparatus consisting of a round-bottomed flask of suitable capacity connected to a condenser by means of a splash head

Note 1

The different types of equipment approved and recommended for this determination are reproduced, showing all the features of construction, in Figures 1, 2, 3 and 4.

5.2. Pipettes of 10, 20, 25, 50, 100 and 200 ml

5.3. A 500-ml graduated flask

5.4. Rotary shaker (35 to 40 turns per minute)

6. PREPARATION OF THE SAMPLE

See Method 1.

7. METHOD OF ANALYSIS

7.1. Preparation of the solution

Carry out a solubility test on the sample in water at room temperature and in the proportion of 2 % (W/V). Weigh to 0.001 g, according to the indications in Table 1, a quantity of 5 or 7 or 10 g of the prepared sample and place it in a 500-ml graduated flask. According to the result of the solubility test, proceed as follows:

a) Products completely soluble in water Add to the flask the quantity of water needed to dissolve the sample; shake, and when completely dissolved, make up the volume and mix thoroughly.

b) Products not completely soluble in water Add to the flask 50 ml of water and then 20 ml of hydrochloric acid (4.1). Shake. Leave undisturbed until the evolution of carbon dioxide has ceased. Add 400 ml of water and shake for half an hour with the rotary shaker (5.4). Make up the volume with water, mix and filter through a dry filter into a dry receptacle.

7.2. Analysis of the solution

According to the variant chosen, place in the receiving flask a measured quantity of standard sulphuric acid as indicated in Table 1. Add the appropriate quantity of the chosen indicator solution (4.9.1 or 4.9.2) and, if necessary, water in order to obtain a volume of at least 50 ml. The end of the extension tube of the condenser must be below the surface of the solution.

Transfer by precision pipette, according to the details given in the table, an aliquot portion [26] of the clear solution, into the distilling flask of the apparatus. Add water in order to obtain a total volume of about 350 ml, and several grains of pumice in order to control the boiling.

[26] The quantity of ammoniacal nitrogen contained in the aliquot part taken according to Table 1 will be approximately: - 0.05 g for variant a, - 0.10 g for variant b, - 0.20 g for variant c.

Assemble the distillation apparatus, and taking care to avoid any loss of ammonia, add to the contents of the distillation flask 10 ml of concentrated sodium hydroxide solution (4.8) or 20 ml of the reagent in the cases where one has used 20 ml hydrochloric acid (4.1) in order to dissolve the test sample. Gradually warm the flask, to avoid boiling vigorously. When boiling commences, distil at the rate of about 100 ml in 10 to 15 minutes; the total volume of distillate should be about 250 ml [27]. When no more ammonia is likely to be evolved, lower the receiving flask so that the tip of the condenser extension is above the surface of the liquid.

[27] The condenser must be regulated so that a continuous flow of condensate is ensured. The distillation should be completed in 30 to 40 minutes.

Test the subsequent distillate by means of an appropriate reagent to ensure that all the ammonia is completely distilled. Wash the condenser extension with a little water and titrate the surplus acid with the standard solution of sodium or potassium hydroxide prescribed for the variant adopted (see Note 2).

Note 2

Standard solutions of different strengths may be used for the back titration provided that the volumes used for the titration do not, as far as possible, exceed 40 to 45 ml.

7.3. Blank

Make a blank test under the same conditions and refer to this in the calculation of the final result.

7.4. Control test

Before carrying out analyses, check that the apparatus is working properly and that the correct application of the Method is used, using an aliquot part of a freshly prepared solution of ammonium sulphate (4.11) containing the maximum quantity of nitrogen prescribed for the chosen variant.

8. EXPRESSION OF THE RESULT

Express the result of the analysis as the percentage of ammoniacal nitrogen in the fertilizer as received for analysis.

9. ANNEXES

As specified in Note 1 in 5.1 "Apparatus", Figures 1, 2, 3 and 4 refer to construction features of the different types of equipment used in this document.

Table 1. - Determination of the ammoniacal nitrogen and of the ammoniacal and nitrate nitrogen in fertilizers

Table of the weighing, dilution and calculation to be carried out for each of the variants a, b and c of the method

Variant a

Approximate maximum quantity of nitrogen to be distilled: 50 mg.

Sulphuric acid 0.1 mol/l to be placed in the receiving flask: 50 ml.

Back titration with NaOH or KOH 0.1 mol/l.

>TABLE POSITION>

Variant b

Approximate maximum quantity of nitrogen to be distilled: 100 mg.

Sulphuric acid 0.2 mol/l to be placed in the receiving flask: 50 ml.

Back titration with NaOH or KOH 0.2 mol/l.

>TABLE POSITION>

Variant c

Approximate maximum quantity of nitrogen to be distilled: 200 mg.

Sulphuric acid 0.5 mol/l to be placed in the receiving flask: 35 ml.

Back titration with NaOH or KOH 0.5 mol/l.

>TABLE POSITION>

Figure 1

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Figure 2

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Figure 3

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Figure 4

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Key to Figures 1, 2, 3 and 4

Figure 1

a) A round-bottomed, long-necked flask of 1 000 ml capacity.

b) Distillation tube with a splash head, connected to the condenser by means of a spherical joint (No 18) (the spherical joint for the connection to the condenser may be replaced by an appropriate rubber connection).

c) Funnel with a teflon tap for the addition of sodium hydroxide (the tap may likewise be replaced by a rubber connection with a clip).

d) A six-bulb condenser with spherical joint (No 18) at the entrance, and joined at the issue to a glass extension tube by means of a small rubber connection (when the connection to the distillation tube is effected by means of a rubber tube, the spherical joint may be replaced by a suitable rubber bung).

e) A 500-ml flask in which the distillate is collected.

The equipment is made of borosilicate glass.

Figure 2

a) A round-bottomed, short-necked flask of 1 000 ml capacity with a spherical joint (No 35).

b) Distillation tube with a splash head, equipped with a spherical joint (No 35) at the entrance and a spherical joint (No 18) at the issue, connected at the side to a funnel with a teflon tap for the addition of sodium hydroxide.

c) A six-bulb condenser with a spherical joint (No 18) at the entrance and joined at the issue to a glass extension tube by means of a small rubber connection.

d) A 500-ml flask in which the distillate is collected.

The equipment is made of borosilicate glass.

Figure 3

a) A round-bottomed, long-necked flask of 750 or 1 000 ml capacity with, a bell mouth.

b) Distillation tube with a splash head and a spherical joint (No 18) at the issue.

c) An elbow tube with a spherical joint (No 18) at the entrance, and a drip cone (the connection to the distillation tube may be effected by means of a rubber tube instead of a spherical joint).

d) A six-bulb condenser joined at the issue to a glass extension tube by means of a small rubber connection.

e) A 500-ml flask in which the distillate is collected.

The equipment is made of borosilicate glass.

Figure 4

a) A round-bottomed, long-necked flask of 1,000 ml capacity with a bell mouth.

b) Distillation tube with a splash head and a spherical joint (No 18), at the issue, connected at the side to a funnel with a teflon tap for the addition of sodium hydroxide (a suitable rubber bung may be used instead of the spherical joint; the tap may be replaced by a rubber connection with an appropriate clip).

c) A six-bulb condenser with a spherical joint (No 18) at the entrance, joined at the issue, by a rubber connection, to a glass extension tube (when the connection to the distillation tube is effected by means of a rubber tube, the spherical joint may be replaced by a suitable rubber bung).

d) A 500-ml flask for the collection of the distillate.

The equipment is made of borosilicate glass.

Methods 2.2 DETERMINATION OF NITRIC AND AMMONIACAL NITROGEN

Method 2.2.1 DETERMINATION OF NITRIC AND AMMONIACAL NITROGEN ACCORDING TO ULSCH

1. SCOPE

This document defines the procedure for the determination of nitrate and ammoniacal nitrogen with reduction according to Ulsch.

2. FIELD OF APPLICATION

All nitrogenous fertilizers, including compound fertilizers, in which nitrogen is found exclusively in nitrate form, or in ammoniacal and nitrate form.

3. PRINCIPLE

Reduction of nitrates and nitrites to ammonia by means of metallic iron in an acid medium, and displacement of the ammonia thus formed by the addition of an excess of sodium hydroxide: distillation of the ammonia, and determination of the yield of ammonia in a known volume of standard sulphuric acid solution. Titration of the excess sulphuric acid by means of a standard solution of sodium or potassium hydroxide.

4. REAGENTS

Distilled or demineralized water, free from carbon dioxide and all nitrogenous compounds.

4.1. Dilute hydrochloric acid: one volume of HCl (d20 = 1.18 g/ml) plus one volume of water

4.2. Sulphuric acid: 0.1 mol/l

4.3. Sodium or potassium hydroxide solution, carbonate free: 0.1 mol/l

4.4. Sulphuric acid solution, approximately 30 % H2SO4 (W/V), ammonia free

4.5. Powdered iron reduced in hydrogen (the prescribed quantity of iron must be able to reduce at least 0.05 g of nitrate nitrogen)

4.6. Sodium hydroxide solution, approximately 30 % NaOH (d20 = 1.33 g/ml), ammonia free

4.7. Indicator solutions

4.7.1. Mixed indicator

Solution A: Dissolve 1 g of methyl red in 37 ml of 0.1 mol/l sodium hydroxide solution and make up to one litre with water.

Solution B: Dissolve 1 g of methylene blue in water and make up to one litre.

Mix one volume of A with two volumes of B.

This indicator is violet in acid solution, grey in neutral solution and green in alkaline solution. Use 0.5 ml (10 drops).

4.7.2. Methyl red indicator solution

Dissolve 0.1 g of methyl red in 50 ml of 95% ethanol. Make up to 100 ml with water and filter if necessary.

This indicator may be used (four to five drops) instead of the preceding one.

4.8. Anti-bump granules of pumice stone, washed in hydrochloric acid and calcined

4.9. Sodium nitrate for analysis

5. APPARATUS

See Method 2.1 "Determination of ammoniacal nitrogen".

6. PREPARATION OF THE SAMPLE

See Method 1 "Preparation of the sample".

7. METHOD OF ANALYSIS

7.1. Preparation of the solution

See Method 2.1 "Determination of ammoniacal nitrogen".

7.2. Procedure

Place in the receiving flask an exactly measured quantity of 50 ml of standard sulphuric acid as indicated in Table 1 of Method 2.1 (variant a) and add the appropriate quantity of indicator solution 4.7.1 or 4.7.2. The end of the extension tube of the condenser must be below the surface of the standard acid in the receiving flask.

Using a precision pipette, transfer an aliquot part of the clear solution as indicated in Table 1 of Method 2.1 (variant a) and place it in the distilling flask of the apparatus. Add 350 ml of water, 20 ml of 30 % sulphuric acid solution (4.4) stir, and add 5 g of reduced iron (4.5). Wash the neck of the flask with several millilitres of water, and place in the neck of the flask a small, long-stemmed funnel. Heat in a boiling water bath for an hour and then wash the stem of the funnel with a few millilitres of water.

Taking care to avoid any loss of ammonia, add to the contents of the distilling flask 50 ml of concentrated sodium hydroxide solution (4.6), or in the cases where 20 ml of hydrochloric acid (1 + 1) (4.1) has been used to dissolve the sample, add 60 ml of concentrated sodium hydroxide solution (4.6). Assemble the distillation apparatus. Distil the ammonia according to the procedure given in Method 2.1.

7.3. Blank test

Carry out a blank test (omitting the sample) under the same conditions and refer to this in the calculation of the final result.

7.4. Control test

Before analysis, check that the apparatus is working properly and that the correct application of the Method is used by using an aliquot part of a freshly prepared solution of sodium nitrate (4.9) containing 0.045 to 0.050 g of nitrogen.

8. EXPRESSION OF THE RESULT

Express the result of analysis as a percentage of nitrate nitrogen or combined ammoniacal and nitrate nitrogen contained in the fertilizer as received for analysis.

Method 2.2.2 DETERMINATION OF NITRIC AND AMMONIACAL NITROGEN ACCORDING TO ARND

1. SCOPE

This document defines the procedure for the determination of nitric and ammoniacal nitrogen with reduction according to Arnd (modified for each of the variants a, b and c).

2. FIELD OF APPLICATION

See Method 2.2.1.

3. PRINCIPLE

Reduction of nitrates and nitrites to ammonia in a neutral aqueous solution by means of a metallic alloy composed of 60 % Cu and 40 % Mg (Arnd's alloy) in the presence of magnesium chloride (MgCl2).

Distillation of the ammonia, and determination of the yield in a known volume of standard sulphuric acid solution. Titration of the excess acid by means of a standard solution of sodium or potassium hydroxide.

4. REAGENTS

Distilled or demineralized water, free from carbon dioxide and all nitrogenous compounds.

4.1. Dilute hydrochloric acid: one volume of HCl (d = 1.18) plus one volume of water

>TABLE POSITION>

4.8. Sodium hydroxide solution: approximately 2 mol/l

4.9. Arnd's alloy for analysis: powdered so as to pass through a seive with apertures less than 1 mm square

4.10. 20 % magnesium chloride solution

Dissolve 200 g of magnesium chloride (MgCl2 . 6H2O) in approximately 600 to 700 ml of water in a one-litre, flat-bottomed flask. To prevent frothing, add 15 g of magnesium sulphate (MgSO4 . 7H2O).

After dissolution add 2 g of magnesium oxide and a few anti-bump granules of pumice stone, and concentrate the suspension to 200 ml by boiling, thus expelling any trace of ammonia from the reagents. Cool, make up the volume to one litre and filter.

4.11. Indicator solutions

4.11.1. Mixed indicator

Solution A: Dissolve 1 g of methyl red in 37 ml of 0.1 mol/l sodium hydroxide solution and make up to one litre with water.

Solution B: Dissolve 1 g of methylene blue in water and make up to one litre.

Mix one volume of A with two volumes of B.

This indicator is violet in acid solution, grey in neutral solution and green in alkaline solution. Use 0.5 ml (10 drops).

4.11.2. Methyl red indicator solution

Dissolve 0.1 g if methyl red in 50 ml of 95 % ethanol. Make up to 100 ml with water and filter if necessary. This indicator may be used (four or five drops) instead of the preceding one.

4.11.3. Congo red indicator solution

Dissolve 3 g of Congo red in one litre of warm water and filter if necessary after cooling. This indicator may be used, instead of the two described above, in the neutralization of acid extracts before distillation, using 0.5 ml per 100 ml of liquid to be neutralized.

4.12. Anti-bump granules of pumice stone washed in hydrochloric acid and calcined

4.13. Sodium nitrate for analysis

5. APPARATUS

See Method 2.1 "Determination of ammoniacal nitrogen".

6. PREPARATION OF THE SAMPLE

See Method 1.

7. METHOD OF ANALYSIS

7.1. Preparation of the solution for analysis

See Method 2.1 "Determination of ammoniacal nitrogen".

7.2. Analysis of the solution

According to the chosen variant, place in the receiving flask the exactly measured quantity of standard sulphuric acid as indicated in Table 1 of Method 2.1. Add the appropriate quantity of chosen indicator solution (4.11.1 or 4.11.2) and finally, sufficient water to give a volume of at least 50 ml. The end of the extension tube of the condenser must be below the surface of the solution.

Using a precision pipette, take, according to Table 1, an adequate aliquot of the clear solution. Place it in the distillation flask.

Add sufficient water to obtain a total volume of about 350 ml (see Note 1), 10 g of Arnd's alloy (4.9), 50 ml of magnesium chloride solution (4.10) and a few fragments of pumice stone (4.12). Rapidly connect the flask to the distillation apparatus. Heat gently for about 30 minutes. Then increase the heating to distil the ammonia. Continue the distillation for about an hour. After this time, the residue in the flask ought to have a syrupy consistency. When the distillation has finished, titrate the quantity of excess acid in the receiving task according to the procedure in Method 2.1.

Note 1

When the sample solution is acid (addition of 20 ml of HCl (4.1) to dissolve the sample) the aliquot part taken for analysis is neutralized in the following way: to the distillation flask containing the taken aliquot part add about 250 ml of water, the necessary quantity of one of the indicators (4.11.1, 4.11.2, 4.11.3) and shake carefully.

Neutralize with 2 mol/l sodium hydroxide solution (4.8) and acidify again with a drop of hydrochloric acid (4.1). Then proceed as indicated in 7.2 (second line).

7.3. Blank test

Carry out a blank test (omitting the sample) under the same conditions and refer to this in the calculation of the final result.

7.4. Control test

Before analysis, check that the apparatus is working properly and that the correct technique is applied using a freshly prepared solution of sodium nitrate (4.13) containing 0.050 to 0.150 g of nitrate nitrogen depending on the variant chosen.

8. EXPRESSION OF THE RESULT

See Method 2.2.1.

Method 2.2.3 DETERMINATION OF NITRIC AND AMMONIACAL NITROGEN ACCORDING TO DEVARDA

1. SCOPE

This document defines the procedure for the determination of nitrate and ammoniacal nitrogen with reduction according to Devarda (modified for each of the variants a, b and c).

2. FIELD OF APPLICATION

See Method 2.2.1.

3. PRINCIPLE

Reduction of nitrates and nitrites to ammonia in a strongly alkaline solution by means of a metallic alloy composed of 45 % Al, 5 % Zn and 50 % Cu (Devarda alloy). Distillation of the ammonia and determination of the yield in a known volume of standard sulphuric acid; titration of the excess sulphuric acid by means of a standard solution of sodium or potassium hydroxide.

4. REAGENTS

Distilled or demineralized water, free from carbon dioxide and all nitrogenous compounds.

4.1. Dilute hydrochloric acid: one volume of HCl (d = 1.18) plus one volume of water

>TABLE POSITION>

4.8. Devarda alloy for analysis

Powdered so that 90 to 100 % will pass through a sieve with apertures less than 0.25 mm square, 50 to 75 % will pass through a sieve with apertures of less than 0.075 mm square.

Pre-packed bottles containing a maximum of 100 g are recommended.

4.9. Sodium hydroxide solution, approximately 30 % NaOH (d20 = 1.33 g/ml), ammonia free

4.10. Indicator solutions

4.10.1. Mixed indicator

Solution A: Dissolve 1 g of methyl red in 37 ml of 0.1 mol/l sodium hydroxide solution and make up to one litre with water.

Solution B: Dissolve 1 g of methylene blue in water and make up to one litre.

Mix one volume of A with two volumes of B.

This indicator is violet in acid solution, grey in neutral solution and green in alkaline solution. Use 0.5 ml (10 drops).

4.10.2. Methyl red indicator

Dissolve 0.1 g if methyl red in 50 ml of 95 % ethanol. Make up to 100 ml with water and filter if necessary.

This indicator (four or five drops) may be used instead of the preceding one.

4.11. Ethanol, 95 to 96 %

4.12. Sodium nitrate for analysis

5. APPARATUS

See Method 2.1.

5.1. Distillation apparatus consisting of a round-bottomed flask of suitable capacity, connected to a condenser by a distilling tube with a splash head, equipped, in addition, with a bubble trap on the receiving flask to prevent any loss of ammonia

The type of apparatus approved for this determination is reproduced, showing all the features of construction, in Figure 5.

5.2. Pipettes of 10, 20, 25, 50, 100 and 200 ml

5.3. A 500-ml graduated flask

5.4. Rotary shaker (35 to 40 turns a minute)

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Preparation of the solution for analysis

See Method 2.1 "Determination of ammoniacal nitrogen".

7.2. Analysis of the solution

The quantity of nitric nitrogen present in the aliquot part of the solution must not exceed the maximum quantity expressed in Table 1.

According to the variant chosen, place in the receiving flask an exactly measured quantity of standard sulphuric acid as indicated in Table 1. Add the appropriate quantity of the chosen indicator solution (4.10.1 or 4.10.2) and finally, sufficient water to give a volume of 50 ml. The end of the extension tube of the condenser must be underneath the surface of the solution. Fill the bubble trap with distilled water.

Using a precision pipette, take an aliquot part as indicated in Table 1 of Method 2.1. Place it in the distillation flask.

Add sufficient water to the distillation flask to obtain a volume of 250 to 300 ml, 5 ml ethanol (4.11) and 4 g Devarda's alloy (4.8). (See Note 2).

Taking the necessary precautions to avoid loss of ammonia, add to the flask about 30 ml of 30 % sodium hydroxide solution (4.9) and finally, in the case of acid soluble samples an additional quantity sufficient to neutralize the quantity of hydrochloric acid (4.1) present in the aliquot part taken for the analysis. Connect the distillation flask to the apparatus, ensuring the tightness of connections. Carefully shake the flask to mix the contents.

Warm gently, so that the release of hydrogen decreases appreciably over about half an hour and the liquid will boil. Continue the distillation, increasing the heat so that at least 200 ml liquid distils in about 30 minutes (do not prolong the distillation beyond 45 minutes).

When the distillation is complete, disconnect the receiving flask from the apparatus, carefully wash the extension tube and bubble trap, collecting the rinsings in the titration flask. Titrate the excess acid according to the procedure in Method 2.1.

Note 2

In the presence of calcium salts such as calcium nitrate and calcium ammonium nitrate, it is necessary to add before distillation for each gram of sample present in the aliquot, 0.700 g sodium phosphate (Na2HPO4 . 2H2O) to prevent the formation of Ca(OH)2.

7.3. Blank test

Carry out a blank test under the same conditions and refer to this in the calculation of the final results.

7.4. Control test

Before carrying out the analysis, check that the apparatus is working properly and that the correct application of the Method is used, using an aliquot of a freshly prepared solution of sodium nitrate (4.12) containing, according to the variant chosen, 0.050 to 0.150 g of nitrate nitrogen.

8. EXPRESSION OF THE RESULT

See Method 2.2.1.

Figure 5

>REFERENCE TO A GRAPHIC>

Key to Figure 5

a) A 750-ml (1 000 ml) round-bottomed, long-necked flask with a bell mouth.

b) Distillation tube with a splash head and an No 18 spherical joint at the issue.

c) Elbow tube with an No 18 spherical joint at the entrance, and a drip cone at the issue (a suitable rubber connection may be used instead of the spherical joint).

d) A six-bulb condenser with an extension tube mounted on a rubber bung holding a bubble trap.

e) A 750-ml receiving flask.

f) A bubble trap to prevent loss of ammonia.

The equipment is made of borosilicate glass.

Method 2.3 DETERMINATION OF TOTAL NITROGEN

Method 2.3.1 DETERMINATION OF THE TOTAL NITROGEN IN CALCIUM CYANAMIDE NITRATE FREE

1. SCOPE

This document defines the procedure for the determination of total nitrogen in nitrate free, calcium cyanamide.

2. FIELD OF APPLICATION

Exclusively to calcium cyanamide (nitrate free).

3. PRINCIPLE

After Kjeldahl digestion, the ammoniacal nitrogen formed is displaced by sodium hydroxide, collected and estimated in a standard solution of sulphuric acid.

4. REAGENTS

Distilled or demineralized water, free from carbon dioxide and all nitrogenous compounds.

4.1. Dilute sulphuric acid (d20 = 1.54 g/ml): one volume of sulphuric acid (d20 = 1.84g/ml) plus one volume of water

4.2. Potassium sulphate for analysis

4.3. Copper oxide (CuO): 0.3 to 0.4 g for each estimation, or an equivalent quantity of copper sulphate pentahydrate (CuSO4 . 5H2O), from 0.95 to 1.25 g for each estimation

4.4. Sodium hydroxide solution, approximately 30 % NaOH (d20 = 1.33 g/ml), ammonia free

>TABLE POSITION>

4.11. Indicator solutions

4.11.1. Mixed indicator

Solution A: Dissolve 1 g of methyl red in 37 ml of 0.1 mol/l sodium hydroxide solution and make up to one litre with water.

Solution B: Dissolve 1 g of methylene blue in water and make up to one litre.

Mix one volume of A with two volumes of B.

This indicator is violet in acid solution, grey in neutral solution and green in alkaline solution. Use 0.5 ml (10 drops).

4.11.2. Methyl red indicator

Dissolve 0.1 g if methyl red in 50 ml of 95 % ethanol and make up to 100 ml with water. Filter if necessary. This indicator (four or five drops) may be used instead of the preceding one.

4.12. Anti-bump granules of pumice stone, washed in hydrochloric acid and calcined

4.13. Potassium thiocyanate for analysis

5. APPARATUS

5.1. Distilling apparatus, see Method 2.1 "Determination of ammoniacal nitrogen"

5.2. A long-necked Kjeldahl flask of suitable capacity

5.3. Pipettes of 50, 100 and 200 ml

5.4. A 250-ml graduated flask

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Preparation of the solution for analysis

Weigh, to the nearest 0.001 g, 1 g of the sample and place it in the Kjeldahl flask. Add 50 ml of diluted sulphuric acid (4.1), 10 to 15 g of potassium sulphate (4.2), and the prescribed catalyst (4.3). Heat slowly to drive off the water, boil gently for two hours, allow to cool, and dilute with 100 to 150 ml of water. Cool again, transfer quantitatively the suspension to a graduated 250-ml flask, make up the volume with water, shake, and filter through a dry filter into a dry flask.

7.2. Analysis of the solution

With a pipette, transfer, according to the variant chosen (see Method 2.1), 50, 100 or 200 ml of the solution thus obtained, and distil the ammonia as described in Method 2.1, adding sufficient NaOH solution (4.4) to ensure a considerable excess.

7.3. Blank test

Carry out a blank test (omitting the sample) under the same conditions and refer to this in the calculation of the final result.

7.4. Control test

Before carrying out the analysis, check that the apparatus is working properly and that the correct application of the Method is used, using an aliquot part of a standard solution of potassium thiocyanate (4.13), approximating to the concentration of nitrogen in the sample.

8. EXPRESSION OF THE RESULT

Express the result as the percentage of nitrogen (N) contained in the fertilizer as received for analysis.

Variant a:

% N = (50 - A) ( 0.7

Variant b:

% N = (50 - A) ( 0.7

Variant c:

% N = (35 - A) ( 0.875

Method 2.3.2 DETERMINATION OF TOTAL NITROGEN IN CALCIUM CYANAMIDE CONTAINING NITRATES

1. SCOPE

This document defines the procedure for the determination of total nitrogen in calcium cyanamide.

2. FIELD OF APPLICATION

The Method is applicable to calcium cyanamide containing nitrates.

3. PRINCIPLE

The direct application of Kjeldahl's Method cannot be applied to calcium cyanamides containing nitrates. For this reason the nitrate nitrogen is reduced to ammonia with metallic iron and stannous chloride before Kjeldahl digestion.

4. REAGENTS

Distilled or demineralized water, free from carbon dioxide and all nitrogenous compounds.

4.1. Sulphuric acid (d20 = 1.84 g/ml)

4.2. Powdered iron reduced in hydrogen

4.3. Potassium sulphate, finely pulverized, for analysis

>TABLE POSITION>

4.10. Indicator solutions

4.10.1. Mixed indicator

Solution A: Dissolve 1 g of methyl red in 37 ml of 0.1 mol/l sodium hydroxide solution and make up to one litre with water.

Solution B: Dissolve 1 g of methylene blue in water and make up to one litre.

Mix one volume of A with two volumes of B.

This indicator is violet in acid solution, grey in neutral solution and green in alkaline solution. Take 0.5 ml (10 drops) of this indicator solution.

4.10.2. Methyl red indicator

Dissolve 0.1 g if methyl red in 50 ml of 95 % ethanol, make up to 100 ml with water and filter if necessary. This indicator (four or five drops) may be used instead of the preceding one.

4.11. Solution of stannous chloride

Dissolve 120 g of SnCl2 . 2H2O in 400 ml of concentrated hydrochlorine acid (d20 = 1.18g/ml) and make up to one litre with water. The solution must be completely clear and prepared immediately before use. It is essential to check the reducing power of the stannous chloride.

Note

Dissolve 0.5 g of SnCl2 . 2H2O in 2 ml of concentrated hydrochloric acid (d20 = 1.18g/ml) and make up to 50 ml with water. Then add 5 g of Rochelle salt (potassium sodium tartrate) and a sufficient quantity of sodium bicarbonate for analysis for the solution to show an alkaline reaction to a litmus paper test.

Titrate with 0.1 mol/l iodine solution in the presence of a starch solution as an indicator.

1 ml of iodine solution 0.1 mol/l corresponds to 0.01128 g of SnCl2 . 2H2O.

At least 80 % of the total tin present in the solution thus prepared must be in a bivalent form. For the titration at least 35 ml of 0.1 mol/l iodine solution should be used.

4.12. Solution of sodium hydroxide containing about 30 % NaOH (d20 = 1.33 g/ml), ammonia free

4.13. Standard nitrate-ammoniacal solution

Weigh out 2.5 g of potassium nitrate for analysis and 10.16 g of ammonium sulphate for analysis and place them in a 250-ml graduated flask. Dissolve in water and make up to 250 ml. 1 ml of this solution contains 0.01 g of nitrogen.

4.14. Pumice stone anti-bump granules, washed in hydrochloric acid and calcined

5. APPARATUS

See Method 2.3.1.

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Preparation of the solution

Weigh, to the nearest 0.001 g, 1 g of the sample and place it in the Kjeldahl flask. Add 0.5 g of powdered iron (4.2) and 50 ml of the stannous chloride solution (4.11), stir and leave standing for half an hour. During the time it is left standing, stir again after 10 and 20 minutes. Then add 10 g of potassium sulphate (4.3) and 30 ml of sulphuric acid (4.1). Boil and carry on the process for an hour after the appearance of white fumes. Leave to cool and dilute with 100 to 150 ml of water. Transfer the suspension quantitatively into a 250-ml graduated flask, cool and make up the volume with water, stir and filter through a dry filter into a dry container. Instead of then siphoning off the suspension in order to apply the variant a, b or c, used in Method 2.1, the ammoniacal nitrogen in this solution may also be distilled directly, after adding sufficient sodium hydroxide to ensure a large surplus (4.12).

7.2. Analysis of the solution

With a pipette, transfer, according to the variant a, b or c, used in Method 2.1, 50, 100 or 200 ml of the solution thus obtained. Distil the ammonia according to the process described in Method 2.1, taking care to add to the distillation flask sufficient sodium hydroxide solution (4.12) to ensure a large excess.

7.3. Blank test

Carry out a blank test (omitting the sample) under the same conditions and refer to this in the calculation of the final result.

7.4. Control test

Before carrying out the analysis, check that the apparatus is working properly and that the correct application of the Method is used with a standard solution (4.13) containing quantities of ammoniacal and nitrate nitrogen comparable to the quantities of cyanamide and nitrate nitrogen contained in nitrated calcium cyanamide.

For this purpose place 20 ml of the standard solution (4.13) in the Kjeldahl flask.

Carry out the analysis according to the Method described in 7.1 and 7.2.

8. EXPRESSION OF THE RESULT

The result of the analysis must be expressed as the percentage of total nitrogen (N) contained in the fertilizer as received for analysis.

Variant a:

% N = (50 - A) ( 0.7

Variant b:

% N = (50 - A) ( 0.7

Variant c:

% N = (35 - A) ( 0.875

Method 2.3.3 DETERMINATION OF TOTAL NITROGEN IN UREA

1. SCOPE

This document defines the procedure for the determination of total nitrogen in urea.

2. FIELD OF APPLICATION

This Method is applied exclusively to urea fertilizers which are nitrate free.

3. PRINCIPLE

Urea is transformed quantitatively into ammonia by boiling in the presence of sulphuric acid. The ammonia thus obtained is distilled from an alkaline medium, the distillate being collected in an excess of standard sulphuric acid. The excess acid is titrated by means of a standard alkaline solution.

4. REAGENTS

Distilled or demineralized water, free from carbon dioxide and all nitrogenous compounds.

4.1. Sulphuric acid, concentrated (d20 = 1.84 g/ml)

4.2. Sodium hydroxide solution, approximately 30 % NaOH (d20 = 1.33 g/ml), ammonia free

>TABLE POSITION>

4.9. Indicator solutions

4.9.1. Mixed indicator

Solution A: Dissolve 1 g of methyl red in 37 ml of 0.1 mol/l sodium hydroxide solution and make up to one litre with water.

Solution B: Dissolve 1 g of methylene blue in water and make up to one litre.

Mix one volume of A with two volumes of B.

This indicator is violet in acid solution, grey in neutral solution and green in alkaline solution. Use 0.5 ml (10 drops).

4.9.2. Methyl red indicator solution

Dissolve 0.1 g if methyl red in 50 ml of 95 % ethanol and make up to 100 ml with water. Filter if necessary. This indicator (four or five drops) may be used instead of the preceding one.

4.10. Anti-bump granules of pumice stone, washed in hydrochloric acid and calcined

4.11. Urea for analysis

5. APPARATUS

5.1. Distillation apparatus, see Method 2.1 "Determination of ammoniacal nitrogen"

5.2. A 500-ml graduated flask

5.3. Pipettes of 25, 50 and 100 ml

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Preparation of the solution

Weigh, to the nearest 0.001 g, 2.5 g of the prepared sample, place it in a 300-ml Kjeldahl flask and moisten with 20 ml water. Stir in 20 ml of concentrated sulphuric acid (4.1) and add a few glass beads to prevent bumping. To prevent splashing, place a long-stemmed glass funnel in the neck of the flask. Heat, slowly at first, then increase the heat until white fumes are observed (30 to 40 minutes).

Cool and dilute with 100 to 150 ml water. Quantitatively transfer to a 500-ml volumetric flask, discarding any sediment. Allow to cool to room temperature. Make up the volume with water, mix and, if necessary, filter through a dry filter into a dry receptacle.

7.2. Analysis of the solution

With a precision pipette, transfer 25, 50 or 100 ml of the solution thus obtained into the distillation flask, according to the variant chosen (see Method 2.1). Distil the ammonia as described in Method 2.1, adding sufficient NaOH (d20 = 1.33 g/ml) (4.2) to the distilling flask to ensure a considerable excess.

7.3. Blank test

Carry out a blank test (omitting the sample) under the same conditions and refer to this in the calculation of the final result.

7.4. Control test

Before carrying out the analysis, check that the apparatus is working properly and that the correct application of the Method is used, using an aliquot part of a freshly prepared solution of urea (4.11).

8. EXPRESSION OF THE RESULT

Express the result as the percentage of nitrogen (N) contained in the fertilizer as received for analysis.

Variant a:

% N = (50 - A) ( 1.12

Variant b:

% N = (50 - A) ( 1.12

Variant c:

% N = (35 - A) ( 1.40

Method 2.4 DETERMINATION OF CYANAMIDE NITROGEN

1. SCOPE

This document defines the procedure for the determination of cyanamide nitrogen.

2. FIELD OF APPLICATION

Calcium cyanamide and calcium cyanamide/nitrate mixtures.

3. PRINCIPLE

Cyanamide nitrogen is precipitated as a silver complex and estimated in the precipitate by Kjeldahl's method.

4. REAGENTS

Distilled or demineralized water, free from carbon dioxide and all nitrogenous compounds.

4.1. Glacial acetic acid

4.2. Ammonia solution containing 10 % of ammonia gas by mass (d20 = 0.96 g/ml)

4.3. Ammoniacal silver solution, according to Tollens

Mix 500 ml of 10 % silver nitrate (AgNO3) solution in water with 500 ml of 10 % ammonia (4.2).

Do not expose unnecessarily to light, heat or air. The solution normally keeps for years. As long as the solution remains clear, the reagent is of good quality.

4.4. Concentrated sulphuric acid (d20 = 1.84 g/ml)

4.5. Potassium sulphate for analysis

4.6. Copper oxide (CuO), 0.3 to 0.4 g for each estimation, or an equivalent quantity of copper sulphate pentahydrate (CuSO4 . 5H2O) from 0.95 to 1.25 g for each estimation

4.7. Sodium hydroxide solution, approximately 30 % NaOH (d20 = 1.33 g/ml), ammonia free

4.8. Sulphuric acid: 0.1 mol/l

4.9. Sodium or potassium hydroxide solution: 0.1 mol/l

4.10. Indicator solutions

4.10.1. Mixed indicator

Solution A: Dissolve 1 g of methyl red in 37 ml of 0.1 mol/l sodium hydroxide solution and make up to one litre with water.

Solution B: Dissolve 1 g of methylene blue in water and make up to one litre.

Mix one volume of A with two volumes of B.

This indicator is violet in acid solution, grey in neutral solution and green in alkaline solution. Use 0.5 ml (10 drops).

4.10.2. Methyl red indicator solution

Dissolve 0.1 g of methyl red in 50 ml of 95 % ethanol and make up to 100 ml with water. Filter if necessary. This indicator (four to five drops) may be used instead of the preceding one.

4.11. Anti-bump granules of pumice stone, washed in hydrochloric acid and calcined

4.12. Potassium thiocyanate for analysis

5. APPARATUS

5.1. Distillation apparatus, see Method 2.1 "Determination of ammoniacal nitrogen"

5.2. A 500-ml graduated flask (e.g. Stohmann)

5.3. A long-necked Kjeldahl flask of suitable capacity (300 to 500 ml)

5.4. A 50-ml pipette

5.5. A rotary shaker (35 to 40 turns per minute)

6. PREPARATION

See Method 1.

7. PROCEDURE

7.1. Safety precaution

When using any ammoniacal silver solution safety goggles must be worn. As soon as a thin membrane forms on the surface of the liquid, an explosion may be produced by agitation and the greatest caution is essential.

7.2. Preparation of the solution for analysis

Weigh, to the nearest 0.001 g, 2.5 g of the sample and place it in a small glass mortar. Grind the sample three times with water, pouring off the water after each grinding into a 500-ml graduated Stohmann flask (5.2). Transfer quantitatively the sample into the 500-ml graduated Stohmann flask, washing the mortar, pestle and funnel with water. Make up with water to approximately 400 ml. Add 15 ml of acetic acid (4.1). Shake on the rotary shaker (5.5) for two hours.

Make up to 500 ml with water, mix and filter.

The analysis must be carried out as quickly as possible.

7.3. Analysis of the solution

Transfer 50 ml of the filtrate, into a 250-ml beaker.

Add ammonia solution (4.2) until slightly alkaline and add 30 ml of warm ammoniacal silver nitrate (4.3) in order to precipitate the yellow silver complex of the cyanamide.

Leave overnight, filter and wash the precipitate with cold water until it is completely free of ammonia.

Place the filter and the precipitate, still moist, in a Kjeldahl flask, add 10 to 15 g of potassium sulphate (4.5), the catalyst (4.6), in the prescribed proportion, then 50 ml of water and 25 ml of concentrated sulphuric acid (4.4).

Warm the flask slowly, while shaking it gently until the contents come to the boil. Increase the heat, boil until the contents of the flask become colourless or pale green.

Continue boiling for one hour, then leave to cool.

Transfer the liquid quantitatively from the Kjeldahl flask to the distilling flask, add a few anti-bump granules of pumice stone (4.11) and make up with water to a total volume of approximately 350 ml. Mix and cool.

Distil the ammonia according to Method 2.1, variant a, adding sufficient NaOH solution (4.7) to ensure the presence of a considerable excess.

7.4. Blank test

Carry out a blank test (omitting the sample) under the same conditions and refer to this in the calculation of the final result.

7.5. Control test

Before carrying out the analysis, check that the apparatus is working properly and that the correct application of the Method is used using an aliquot part of a standard solution of potassium thiocyanate (4.12) corresponding to 0.05 g of nitrogen.

8. EXPRESSION OF THE RESULT

Express the result as the percentage of cyanamide nitrogen contained in the fertilizer as received for analysis.

% N = (50 - A) ( 0.56

Method 2.5 SPECTROPHOTOMETRIC DETERMINATION OF BIURET IN UREA

1. SCOPE

This document defines the procedure for the determination of biuret in urea.

2. FIELD OF APPLICATION

The Method is applied exclusively to urea.

3. PRINCIPLE

In an alkaline medium, in the presence of potassium sodium tartrate, biuret and bivalent copper from a violet cupric compound. The absorbance of the solution is measured at a wave length of about 546 nm (nanometer).

4. REAGENTS

Distilled or demineralized water, free from carbon dioxide and ammonia. The quality of this water is particularly important in this determination.

4.1. Methanol

4.2. Sulphuric acid solution, about 0.1 mol/l

4.3. Sodium hydroxide solution, about 0.1 mol/l

4.4. Alkaline solution of potassium sodium tartrate

In a graduated one-litre flask, dissolve 40 g of sodium hydroxide in 500 ml of water and leave to cool. Add 50 g of potassium sodium tartrate (NaKC4H4O6 . 4H2O). Make up to the mark. Leave standing 24 hours before use.

4.5. Solution of copper sulphate

In a graduated one-litre flask, dissolve 15 g of copper sulphate pentahydrate (CuSO4 . 5H2O) in 500 ml of water. Make up to the mark.

4.6. Freshly prepared biuret standard solution

In a 250-ml graduated flask, dissolve 0.250 g of pure biuret [28] in water. Make up to 250 ml. 1 ml of this solution contains 0.001 g of biuret.

[28] Biuret can be purified beforehand by washing with an ammoniacal solution (10 %), then with acetone and drying in a vacuum.

4.7. Indicator solution

In a graduated 100-ml flask, dissolve 0.1 g of methyl red in 50 ml of 95 % ethanol, make up to 100 ml with water. Filter if any insolubles remain.

5. APPARATUS

5.1. Spectrometer or photometer with filters of a sensitivity and precision to permit measures of less than 0.5 % T to be reproduced [29]

[29] See point 9 "Appendix".

5.2. Graduated flasks of 100, 250 and 1 000 ml

5.3. Graduated pipettes of 2, 5, 10, 20, 25 and 50 ml or a 25 ml burette, graduated to 0.05 ml

5.4. A 250-ml beaker

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Preparation of the calibration curve

Transfer 0, 2, 5, 10, 20, 25 and 50 ml of aliquots of biuret standard solution (4.6) into a series of seven graduated 100-ml flasks. Make up the volumes to about 50 ml with water, add one drop of indicator (4.7) and neutralize, if necessary, with sulphuric acid 0.1 mol/l (4.2). Stir in 20 ml of the alkaline tartrate solution (4.4) then 20 ml of the copper sulphate solution (4.5).

Note

These solutions (4.4 and 4.5) must be measured in with two precision burettes or better still with pipettes.

Make up to 100 ml with distilled water, mix and leave standing for 15 minutes at 30 ± 2 °C.

With the "0" biuret standard solution as reference, measure the absorbance of each solution at a wavelength of about 546 nm using cells of a suitable path length.

Plot the calibration curve, using the absorbances as the ordinates and the corresponding quantities of biuret, in milligrams, as the abscissae.

7.2. Preparation of the solution to be analyzed

Weigh, to the nearest 0.001 g, 10 g of the prepared sample; dissolve in about 150 ml of water in a 250-ml graduated flask, and make up to the mark. Filter if necessary.

Remark 1

If the sample for analysis contains more than 0.015 g of ammoniacal nitrogen, dissolve it, in a 250-ml beaker, in 50 ml of methanol (4.1). Reduce by evaporation to a volume of about 25 ml. Transfer quantitatively to a graduated 250-ml flask. Make up to the mark with water. Filter, if necessary, through a dry fluted filter into a dry container.

Remark 2

Elimination of the opalescence: if any colloid substance is present, difficulties may arise during filtering. The solution intended for analysis is in that case prepared as follows: dissolve the sample for analysis in 150 ml of water, add 2 ml of 1 mol/l hydrochloric acid, and filter the solution through two flat very fine filters into a graduated 250-ml flask. Wash the filters with water and make up to volume. Continue the process according to the Method described in 7.3 "Determination".

7.3. Determination

According to the presumed biuret content, transfer 25 or 50 ml from the solution mentioned in 7.2 with a pipette, place this quantity in a 100-ml graduated flask and neutralize if necessary with a 0.1 mol/l reagent (4.2 or 4.3) as required, using methyl red as an indicator and add, with the same accuracy as that used when drawing up a calibration curve, 20 ml of the alkaline solution of potassium sodium tartrate (4.4) and 20 ml of the copper solution (4.5). Make up to volume, mix thoroughly and leave standing for 15 minutes at 30 ± 2 °C.

Then carry out the photometric measurements and calculate the quantity of biuret present in the urea.

8. EXPRESSION OF THE RESULT

>TABLE POSITION>

Where

"C" is the mass, in milligrams, of biuret, read from the calibration graph,

"V" the volume of the aliquot:

9. APPENDIX

"Jo" being the intensity of the beam of monochromatic rays (of a determinate wavelength) before it passes through a transparent body, and "J" being the intensity of this beam after the passage, then:

>TABLE POSITION>

where

s = thickness of the layer in centimetres.

c = concentration in milligrams per litre.

k = specific factor for each substance in the Lambert-Beer law.

Methods 2.6 DETERMINATION OF DIFFERENT FORMS OF NITROGEN IN THE SAME SAMPLE

Method 2.6.1 DETERMINATION OF DIFFERENT FORMS OF NITROGEN IN THE SAME SAMPLE IN FERTILIZERS CONTAINING NITROGEN AS NITRIC, AMMONIACAL, UREA AND CYANAMIDE NITROGEN

1. SCOPE

This document defines the procedure for the determination of any one form of nitrogen in the presence of any other form.

2. FIELD OF APPLICATION

Any fertilizer provided for in Annex I containing nitrogen in various forms.

3. PRINCIPLE

3.1. Total soluble and insoluble nitrogen

According to the list of standard fertilizers (Annex I), this determination is applicable to products containing calcium cyanamide.

3.1.1. In the absence of nitrates, the test sample is mineralized by direct Kjeldahl digestion

3.1.2. In the presence of nitrates, the test sample is mineralized by Kjeldahl digestion after reduction with the aid of metallic iron and stannous chloride

In both cases, the ammonia is determined according to Method 2.1.

Note

If analysis shows an insoluble nitrogen content of more than 0.5%, one concludes that the fertilizer contains other forms of insoluble nitrogen not included in the list in Annex I.

3.2. Forms of soluble nitrogen

The following are determined from different aliquots taken from the same solution of the sample:

3.2.1. total soluble nitrogen:

3.2.1.1. in the absence of nitrates, by direct Kjeldahl digestion,

3.2.1.2. in the presence of nitrates, by Kjeldahl digestion on an aliquot part taken from the solution after reduction according to Ulsch, the ammonia being determined in both cases, as described in Method 2.1;

3.2.2. total soluble nitrogen with the exception of nitrate nitrogen by Kjeldahl digestion after elimination in an acid medium of nitrate nitrogen with ferrous sulphate, the ammonia being determined as described in Method 2.1;

3.2.3. nitrate nitrogen by difference:

3.2.3.1. in the absence of calcium cyanamide, between 3.2.1.2 and 3.2.2 or between total soluble nitrogen (3.2.1.2) and the sum of ammoniacal nitrogen and ureic organic nitrogen (3.2.4 + 3.2.5),

3.2.3.2. in the presence of calcium cyanamide, between 3.2.1.2 and 3.2.2 or between 3.2.1.2 and the sum of 3.2.4 + 3.2.5 + 3.2.6;

3.2.4. ammoniacal nitrogen:

3.2.4.1. solely in the presence of ammoniacal nitrogen and ammoniacal plus nitrate nitrogen, by applying Method 1,

3.2.4.2. in the presence of urea nitrogen and/or cyanamide nitrogen by cold distillation after making slightly alkaline, the ammonia being absorbed in a standard solution of sulphuric acid and determined as described in Method 2.1;

3.2.5. urea nitrogen:

3.2.5.1. by conversion using urease, into ammonia which is titrated with a standard solution of hydrochloric acid,

or

3.2.5.2. by gravimetry with xanthydrol: the co-precipitated biuret can be counted with urea nitrogen without great error, its content remaining generally low in absolute value in compound fertilizers,

or

3.2.5.3. by difference according to the following table:

>TABLE POSITION>

3.2.6. cyanamide nitrogen, by precipitation as a silver compound, the nitrogen being estimated in the precipitate by the Kjeldahl method

4. REAGENTS

Destilled or demineralized water.

4.1. Potassium sulphate for analysis

4.2. Iron powder, reduced with hydrogen (the prescribed quantity of iron must be able to reduce at least 50 mg of nitrate nitrogen)

4.3. Potassium thiocyanate for analysis

4.4. Potassium nitrate for analysis

4.5. Ammonium sulphate for analysis

4.6. Urea for analysis

4.7. Dilute sulphuric acid 1: 1 by volume: one volume of sulphuric acid (d20 = 1.84 g/ml) in one volume of water

4.8. Standard solution of sulphuric acid: 0.2 mol/l

4.9. Concentrated sodium hydroxide solution. Aqueous solution at about 30 % (W/V) of NaOH, free from ammonia

4.10. Standard solution of sodium or potassium hydroxide: 0.2 mol/l, free from carbonates

4.11. Stannous chloride solution

Dissolve 120 g of SnCl2 . 2H2O in 400 ml of concentrated hydrochloric acid (d20 = 1.18 g/ml) and make up to one litre with water. The solution must be perfectly clear and prepared immediately before its use.

Note

It is essential to check the reducing power of stannous chloride: dissolve 0.5 g of SnCl2 . 2H2O in 2 ml of concentrated hydrochloric acid (d20 = 1.18g/ml) and make up to 50 ml with water. Then add 5 g of Rochelle salt (potassium sodium tartrate), then a sufficient quantity of sodium bicarbonate for the solution to be alkaline to litmus paper.

Titrate with a 0.1 mol/l iodine solution in the presence of a starch solution as an indicator.

1 ml of 0.1 mol/l iodine solution corresponds to 0.01128 g of SnCl2 . 2H2O.

At least 80 % of the total tin present in the solution thus prepared must be in bivalent form. For the titration at least 35 ml of 0.1 mol/l iodine solution must therefore be used.

4.12. Sulphuric acid (d 20= 1.84 g/ml)

4.13. Dilute hydrochloric acid: one volume of hydrochloric acid (d20 = 1.18 g/ml) Plus one volume of water

4.14. Acetic acid: 96 to 100 %

4.15. Sulphuric acid solution containing about 30 % of H2SO4 (W/V)

4.16. Ferrous sulphate: crystalline, FeSO4 . 7H2O

4.17. Standard sulphuric acid solution: 0.1 mol/l

4.18. Octyl alcohol

4.19. Saturated solution of potassium carbonate

4.20. Standard solution of sodium or potassium hydroxide: 0.1 mol/l (free from carbonates)

4.21. Saturated solution of barium hydroxide

4.22. Sodium carbonate solution: at 10 % (W/V)

4.23. Hydrochloric acid: 2 mol/l

4.24. Standard solution of hydrochloric acid: 0.1 mol/l

4.25. Urease solution

Suspend 0.5 g of active urease in 100 ml of distilled water. Using hydrochloric acid 0.1 mol/l (4.24), adjust the pH to 5.4, measured by a pH meter.

4.26. Xanthydrol

Solution at 5 % in ethanol or methanol (4.31) (do not use products giving a high proportion of insoluble matter). The solution may be kept for three months in a well-stoppered bottle, away from the light.

4.27. Copper oxide (CuO): 0.3 to 0.4 g per estimation or an equivalent quantity of copper sulphate pentahydrate (CuSO4 . 5H2O) of 0.95 to 1.25 g per estimation

4.28. Anti-bump granules washed in hydrochloric acid and calcined

4.29. Indicator solutions

4.29.1. Solution A: Dissolve 1 g of methyl red in 37 ml of sodium hydroxide solution 0.1 mol/l and make up to one litre with water.

Solution B: Dissolve 1 g of methylene blue in water and make up to one litre.

Mix one volume of A with two volumes of B.

This indicator is violet in acid solution, grey in neutral solution and green in alkaline solution. Use 0.5 ml (10 drops) of this indicator solution.

4.29.2. Methyl red indicator solution

Dissolve 0.1 g of methyl red in 50 ml of 95 % ethanol. Make up to 100 ml with water and filter if necessary. This indicator (four or five drops) can be used instead of the previous one.

4.30. Indicator papers

Litmus bromothymol blue (or other papers sensitive to pH 6 to 8).

4.31. Ethanol or methanol: solution 95 %

5. APPARATUS

5.1. Distillation apparatus

See Method 2.1.

5.2. Apparatus for the estimation of ammoniacal nitrogen according to analytical technique 7.2.5.3 (see Figure 6)

The apparatus is made up of a specially shaped receptacle with a ground glass neck, with a side neck, a connecting tube with a splash head and a perpendicular tube for the introduction of air. The tubes can be connected to the receptacle by means of a simple perforated rubber bung. It is important to give a suitable shape to the end of the tubes introducing air, since the bubbles of gas must be perfectly distributed throughout the solutions contained in the receptacle and the absorber. The best arrangement consists of small mushroom-shaped pieces with an external diameter of 20 mm and six openings of 1 mm around the periphery.

5.3. Apparatus for the estimation of urea nitrogen according to the urease technique (7.2.6.1)

It consists of a 300 ml Erlenmeyer flask, with a separating funnel and a small absorber (see Figure 7).

5.4. Rotary shaker (35 to 40 turns per minute)

5.5. A pH meter

5.6. Adjustable oven

5.7. Glassware:

- pipettes of 2, 5, 10, 20, 25, 50 and 100 ml,

- long-necked Kjeldahl flasks of 300 and 500 ml,

- graduated flasks of 100, 250, 500 and 1 000 ml,

- crucibles of sintered glass, pore diameter, 5 to 15 µ,

- mortars.

6. PREPARATION OF THE SAMPLE

See Method 1.

7. ANALYTICAL TECHNIQUE

7.1. Total soluble and insoluble nitrogen

7.1.1. In the absence of nitrates

7.1.1.1. Digestion

Weigh out, to an accuracy of 0.001 g, a quantity of the sample containing 100 mg of nitrogen at the most. Place it in the flask of the distillation apparatus (5.1). Add 10 to 15 g of potassium sulphate (4.1), the catalyst (4.27), and a few anti-bump granules (4.28). Then add 50 ml of dilute sulphuric acid (4.7), and mix thoroughly. First heat gently mixing from time to time, until foam no longer forms. Then heat so that the liquid boils regularly and keep it boiling for one hour after the solution has become clear, preventing any organic matter from sticking to the sides of the flask. Allow to cool. Carefully add about 350 ml of water, with mixing. Ensure that the dissolution is as complete as possible. Allow to cool and connect the flask to the distillation apparatus (5.1).

7.1.1.2. Distillation of ammonia

Transfer with a precision pipette, into the receiver of the apparatus, 50 ml of a standard solution of sulphuric acid 0.2 mol/l (4.8). Add the indicator (4.29.1 or 4.29.2). Ensure that the tip of the condenser is at least 1 cm below the level of the solution.

Taking the necessary precautions to avoid any loss of ammonia, carefully add to the distillation flasks enough of the concentrated sodium hydroxide solution (4.9) to make the liquid strongly alkaline (120 ml is generally sufficient; check by adding a few drops of phenolphthalein. At the end of the distillation the solution in the flask must still be clearly alkaline). Adjust the heating of the flask so as to distil 150 ml in half an hour. Test with indicator paper (4.30) that the distillation has been completed. If it has not, distil a further 50 ml and repeat the test until the supplementary distillate reacts neutrally to the indicator paper (4.30). Then lower the receiver, distil a few millilitres more and rinse the tip of the condenser. Titrate the excess of acid with a standard solution of potassium or sodium hydroxide 0.2 mol/l (4.10) until the indicator changes colour.

7.1.1.3. Blank test

Carry out a blank test (omitting the sample) under the same conditions and take account of it when calculating the final result.

7.1.1.4. Expression of the result

>TABLE POSITION>

where

a = ml of standard solution of sodium or potassium hydroxide 0.2 mol/l, used for the blank, carried out by pipetting into the receiver of the apparatus (5.1), 50 ml of standard solution of sulphuric acid 0.2 mol/l (4.8),

A = ml of standard solution of sodium or potassium hydroxide 0.2 mol/l, used for the analysis,

M = mass of the test sample, in grams.

7.1.2. In the presence of nitrate

7.1.2.1. Test sample

Mass out, to an accuracy of 0.001 g, a quantity of the sample containing not more than 40 mg of nitrate nitrogen.

7.1.2.2. Reduction of the nitrate

Mix the test sample in a small mortar with 50 ml of water. Transfer with the minimum amount of distilled water into a 500-ml Kjeldahl flask. Add 5 g of reduced iron (4.2) and 50 ml of stannous chloride solution (4.11). Shake and leave it to stand for half an hour. During the time it is standing, stir again after 10 and 20 minutes.

7.1.2.3. Kjeldahl digestion

Add 30 ml of sulphuric acid (4.12), 5 g of potassium sulphate (4.1), the prescribed quantity of catalyst (4.27) and some anti-bump granules (4.28). Heat gently with the flask slightly tilted. Increase the heat slowly and shake the solution frequently to keep the mixture suspended: the liquid darkens and then clears with the formation of a yellow-green anhydrous iron sulphate suspension. Then continue heating for one hour after obtaining a clear solution, maintaining it at simmering point. Leave to cool. Cautiously take the contents of the flask up in a little water and add little by little 100 ml of water. Mix and transfer the contents of the flask into a 500-ml graduated flask. Make up the volume with water. Mix. Filter through a dry filter into a dry receptacle.

7.1.2.4. Analysis of the solution

Transfer by pipette, into the flask of the distillation apparatus (5.1), an aliquot containing 100 mg of nitrogen at the most. Dilute to about 350 ml with distilled water, add a few anti-bump granules (4.28), connect the flask to the distillation apparatus and continue the estimation as described in 7.1.1.2.

7.1.2.5. Blank test

See 7.1.1.3.

7.1.2.6. Expression of the result

>TABLE POSITION>

where

a = ml of standard solution of sodium or potassium hydroxide 0.2 mol/l, used for the blank, carried out by pipetting into the receiver of the apparatus (5.1), 50 ml of standard solution of sulphuric acid 0.2 mol/l (4.8),

A = ml of standard solution of sodium or potassium hydroxide 0.2 mol/l, used for the analysis,

M = mass of the sample, expressed in grams, present in the aliquot part taken in 7.1.2.4.

7.2. Forms of soluble nitrogen

7.2.1. Preparation of the solution to be analyzed

Mass out, to an accuracy of 1 mg, 10 g of the sample and place it in a 500-ml graduated flask.

7.2.1.1. In the case of fertilizers not containing cyanamide nitrogen

Add to the flask 50 ml of water and then 20 ml of dilute hydrochloric acid (4.13). Shake and leave it to stand until the evolution of carbon dioxide ceases. Then add 400 ml of water and shake for half an hour on the rotary shaker (5.4). Make up to the volume with water, mix and filter through a dry filter into a dry receptacle.

7.2.1.2. In the case of fertilizers containing cyanamide nitrogen

Add to the flask 400 ml of water and a few drops of methyl red (4.29.2). If necessary make the solution acid by using acetic acid (4.14). Add 15 ml of acetic acid (4.14). Shake on the rotary shaker for two hours (5.4). If necessary, reacidify the solution during the operation, using acetic acid (4.14). Make up to the volume with water, mix, filter immediately through a dry filter into a dry receptacle and immediately estimate the cyanamide nitrogen.

In both cases, estimate the various soluble forms of nitrogen the same day the solution is made up, starting with the cyanamide nitrogen and urea nitrogen if they are present.

7.2.2. Total soluble nitrogen

7.2.2.1. In the absence of nitrate

Pipette into a 300-ml Kjeldahl flaks, an aliquot of the filtrate (7.2.1.1 or 7.2.1.2), containing 100 mg of nitrogen at the most. Add 15 ml of concentrated sulphuric acid (4.12), 0.4 g of copper oxide or 1.25 g of copper sulphate (4.27) and a few anti-bump granules (4.28). First heat gently to begin the digestion and then at a higher temperature until the liquid become colourless or slightly greenish and white fumes are clearly apparent. After cooling, quantitatively transfer the solution into the distillation flask, dilute to about 500 ml with water, and add a few anti-bump granules (4.28). Connect the flask to the distillation apparatus (5.1) and continue the determination as described in 7.1.1.2.

7.2.2.2. In the presence of nitrate

Transfer with a precision pipette into a 500-ml Erlenmeyer, an aliquot of the filtrate (7.2.1.1 or 7.2.1.2) containing not more than 40 mg of nitrate nitrogen. At this stage of the analysis the total quantity of nitrogen is not important. Add 10 ml of sulphuric acid at 30 % (4.15), 5 g of reduced iron (4.2), and immediately cover the Erlenmeyer with a watch glass. Heat gently until the reaction is steady but not vigorous. At this juncture stop the heating and allow the flask to stand for at least three hours at ambient temperature. With water, quantitatively transfer the liquid into a 250-ml graduated flask, leaving behind the undissolved iron - make up to the mark with the water. Mix thoroughly, and transfer by precision pipette into a 300-ml Kjeldahl flask, an aliquot containing 100 mg of nitrogen at the most. Add 15 ml of concentrated sulphuric acid (4.12), 0.4 g of copper oxide or 1.25 g of copper sulphate (4.27) and some anti-bump granules (4.28). First heat gently to begin the digestion and then at a higher temperature until the liquid becomes colourless or slightly greenish and white fumes are clearly apparent. After cooling, quantitatively transfer the solution into the distillation flask, dilute to approximately 500 ml with water and add some anti-bump granules (4.28). Connect the flask to the distillation apparatus (5.1) and continue the determination as described in 7.1.1.2.

7.2.2.3. Blank test

See 7.1.1.3.

7.2.2.4. Expression of the result

>TABLE POSITION>

where

a = ml of standard solution of sodium or potassium hydroxide 0.2 mol/l, used for the blank, carried out by pipetting into the receiver of the apparatus (5.1), 50 ml of standard solution of sulphuric acid 0.2 mol/l (4.8),

A = ml of standard solution of sodium or potassium hydroxide 0.2 mol/l, used for the analysis,

M = mass of the sample, expressed in grams, present in the aliquot part taken in 7.2.2.1 or 7.2.2.2.

7.2.3. Total soluble nitrogen with the exception of nitrate nitrogen

Transfer with a precision pipette into a 300-ml Kjeldahl flask, an aliquot sample of the filtrate (7.2.1.1 or 7.2.1.2) containing not more than 50 mg of nitrogen to be determined. Dilute to 100 ml with water, add 5 g of ferrous sulphate (4.16), 20 ml of concentrated sulphuric acid (4.12) and some anti-bump granules (4.28). First heat gently and then increase the heat until white fumes appear. Continue the digestion for 15 minutes. Stop the heating, introduce copper oxide (4.27) as a catalyst and keep it at a temperature such that white fumes are emitted for a further 10 to 15 minutes. After cooling, quantitatively transfer the contents to the Kjeldahl flask into the distillation flask of the apparatus (5.1). Dilute to approximately 500 ml with water and add a few anti-bump granules (4.28). Connect the flask to the distillation apparatus and continue the determination as described in 7.1.1.2.

7.2.3.1. Blank test

See 7.1.1.3.

7.2.3.2 Expression of the result

>TABLE POSITION>

where

a = ml of standard solution of sodium or potassium hydroxide 0.2 mol/l, used for the blank, carried out by pipetting into the receiver of the apparatus (5.1), 50 ml of standard solution of sulphuric acid 0.2 mol/l (4.8),

A = ml of standard solution of sodium or potassium hydroxide 0.2 mol/l, used for the analysis,

M = mass of the sample, expressed in grams, present in the aliquot part taken for the estimation.

7.2.4. Nitrate nitrogen

7.2.4.1. In the absence of calcium cyanamide

Is obtained by the difference between the results obtained in 7.2.2.4 and 7.2.3.2 and/or the result obtained in 7.2.2.4 and the sum of the results obtained in (7.2.5.2 or 7.2.5.5) and (7.2.6.3 or 7.2.6.5 or 7.2.6.6).

7.2.4.2. In the presence of calcium cyanamide

Is obtained by the difference between the results obtained in 7.2.2.4 and 7.2.3.2 and between the result obtained in 7.2.2.4 and the sum of the results obtained in (7.2.5.5), (7.2.6.3 or 7.2.6.5 or 7.2.6.6) and (7.2.7).

7.2.5. Ammoniacal nitrogen

7.2.5.1. Solely in the presence of ammoniacal nitrogen and ammoniacal plus nitrate nitrogen

Transfer with a precision pipette into the flask of the distillation apparatus (5.1), an aliquot sample of the filtrate (7.2.1.1) containing 100 mg of ammoniacal nitrogen at the most. Add water to obtain a total volume of about 350 ml and some anti-bump granules (4.28) to facilitate boiling. Connect the flask to the distillation apparatus, add 20 ml of sodium hydroxide solution (4.9) and distil as described in 7.1.1.2.

7.2.5.2. Expression of the result

>TABLE POSITION>

where

a = ml of standard solution of sodium or potassium hydroxide 0.2 mol/l, used for the blank, carried out by pipetting into the receiver of the apparatus (5.1), 50 ml of standard solution of sulphuric acid 0.2 mol/l (4.8),

A = ml of standard solution of sodium or potassium hydroxide 0.2 mol/l, used for the analysis,

M = mass of the sample, expressed in grams, present in the aliquot part taken for the estimation.

7.2.5.3. In the presence of urea and/or cyanamide nitrogen

Transfer with a precision pipette, into the dry flask of the apparatus (5.2), an aliquot sample of the filtrate (7.2.1.1 or 7.2.1.2) containing 20 mg of ammoniacal nitrogen at the most. Then assemble the apparatus. Pipette, into the 300-ml Erlenmeyer, 50 ml of the standard sulphuric acid solution 0.1 mol/l (4.17) and enough distilled water for the level of the liquid to be approximately 5 cm above the opening of the delivery tube. Introduce, through the side neck of the reaction flask, distilled water so as to make up the volume to about 50 ml. Mix. To avoid foaming during aeration, add a few drops of octyl alcohol (4.18). Then make the solution alkaline by using 50 ml of saturated potassium carbonate solution (4.19) and immediately begin to expel the ammonia thus liberated from the cold suspension. The strong current of air necessary to that end (flow of approximately three litres per minute) is purified beforehand by passing it through washing flasks containing dilute sulphuric acid and dilute sodium hydroxide. Instead of using pressurized air, it is also possible to work in a vacuum (water pump) provided that the inflow tube is connected in a sufficiently airtight manner to the receptacle used to recover the ammonia. The elimination of the ammonia is generally complete after three hours. It is nevertheless wise to make sure of that by changing the receiving flask. When the operation is finished, separate the flask from the apparatus, rinse the tip of the tube and the sides of the flask with a little distilled water. Titrate the excess of acid with a standard solution of sodium hydroxide 0.1 mol/l (4.20) until the indicator turns grey (4.29.1).

7.2.5.4. Blank test

See 7.1.1.3.

7.2.5.5. Expression of the result

>TABLE POSITION>

where

a = ml of standard solution of sodium or potassium hydroxide 0.1 mol/l, used for the blank, carried out by pipetting into the 300-ml Erlenmeyer of the apparatus (5.2), 50 ml of standard solution of sulphuric acid 0.1 mol/l (4.17),

A = ml of standard solution of sodium or potassium hydroxide 0.1 mol/l, used for the analysis,

M = mass of the sample, expressed in grams, present in the aliquot part taken for the analysis.

7.2.6. Urea nitrogen

7.2.6.1. Urease method

Transfer with a precision pipette, into a 500-ml graduated flask, an aliquot of the filtrate (7.2.1.1. or 7.2.1.2) containing not more than 250 mg of urea nitrogen. To precipitate the phosphates add some saturated barium hydroxide solution (4.21) until no further precipitation occurs. Then eliminate the excess of barium ions (and any dissolved calcium ions with the aid off the sodium carbonate solution at 10 % (4.22).

Leave it to settle and check whether total precipitation has occurred. Make up to the mark, mix and filter through a pleated filter. Pipette 50 ml of the filtrate into the 300-ml Erlenmeyer of the apparatus (5.3). Acidify the filtrate with hydrochloric acid 2 mol/l (4.23) until a pH of 3.0 measured by the pH meter is obtained (5.5). Then raise the pH to 5.4 with sodium hydroxide 0.1 mol/l (4.20).

To avoid losses of ammonia during decomposition by the urease, close the Erlenmeyer with a stopper provided with a separating funnel and a small bubble trap containing exactly 2 ml of a standard solution of hydrochloric acid 0.1 mol/l (4.24). Introduce through the separating funnel 20 ml of urease solution (4.25), and leave it to stand for one hour at 20 to 25 °C. Then pipette 25 ml of the standard solution of hydrochloric acid 0.1 mol/l (4.24) into the separating funnel, allow it to run through into the solution and then rinse with a little water. In the same way quantitatively transfer the contents of the protective receptacle into the solution contained in the Erlenmeyer. Titrate the excess of acid with the standard solution of sodium hydroxide 0.1 mol/l (4.20), until a pH of 5.4 is obtained, measured by the pH meter.

7.2.6.2. Blank test

See 7.1.1.3.

7.2.6.3. Expression of the result

>TABLE POSITION>

where

a = ml of standard solution of sodium or potassium hydroxide 0.1 mol/l, used for the blank, carried out exactly in the same conditions as the analysis,

A = ml of standard solution of sodium or potassium hydroxide 0.1 mol/l, used for the analysis,

M = mass of the sample, expressed in grams, present in the aliquot part taken for the analysis.

Remark

(1) After precipitation by the solutions of barium hydroxide and sodium carbonate, make up to the mark, filter and neutralize as rapidly as possible.

(2) The titration test may also be carried out with the indicator (4.29.2), but the end point is then more difficult to observe.

7.2.6.4. Gravimetric Method with xanthydrol

Transfer with a precision pipette, into a 250-ml beaker, an aliquot of the filtrate (7.2.1.1. or 7.2.1.2) containing not more than 20 mg of urea. Add 40 ml of acetic acid (4.14). Stir with a glass rod for one minute, leave any precipitate to settle for five minutes. Filter on a flat bed into a 100-ml beaker, wash with several millilitres of acetic acid (4.14), then add to the filtrate drop by drop, 10 ml of xanthydrol (4.26), stirring continuously with a glass rod. Leave it to settle until the precipitate appears, at that juncture, stir again for one or two minutes. Leave it to stand for one and a half hours. Filter through a glass filtering crucible, which has been previously dried and weighed, pressing it down slightly; wash three times with 5 ml of ethanol (4.31) without trying to eliminate all the acetic acid. Place it in the oven and keep it at a temperature of 130 °C for an hour (do not go above 145 °C). Leave it to cool in a desiccator and weigh.

7.2.6.5. Expression of the result

>TABLE POSITION>

where

m1 = mass of the precipitate obtained, in grams,

M2 = mass of the sample, expressed in grams, present in the aliquot part taken for the estimation.

Correct for a blank. Biuret may, generally speaking, be measured with the urea nitrogen without any great error, since its content remains small in absolute value in compound fertilizers.

7.2.6.6. Method by difference

Urea nitrogen may also be calculated according to the following table:

>TABLE POSITION>

7.2.7. Cyanamide nitrogen

Take one aliquot part of the filtrate (7.2.1.2), containing 10 to 30 mg of cyanamide nitrogen and place it in a 250-ml beaker. Continue the analysis according to Method 2.4.

8. VERIFICATION OF THE RESULTS

8.1. In certain cases, a difference may be found between the total nitrogen obtained directly from a weighed out sample (7.1) and total soluble nitrogen (7.2.2). Nevertheless, the difference should not be greater than 0.5 %. If this is not the case, the fertilizer contains forms of insoluble nitrogen not contained in the list in Annex I.

8.2. Before each analysis, check that the apparatus is working properly and that the correct application of the Method is used, with a standard solution including the various forms of nitrogen in proportions similar to those of the test sample. This standard solution is prepared from standard solutions of potassium thiocyanate (4.3), potassium nitrate (4.4), ammonium sulphate (4.5) and urea (4.6).

Figure 6 Apparatus for the estimation of ammoniacal nitrogen (7.2.5.3)

>REFERENCE TO A GRAPHIC>

Figure 7 Apparatus for the estimation of urea nitrogen (7.2.6.1)

>REFERENCE TO A GRAPHIC>

Method 2.6.2 DETERMINATION OF DIFFERENT FORMS OF NITROGEN IN FERTILIZERS CONTAINING NITROGEN ONLY AS NITRIC AMMONIACAL AND UREA NITROGEN

1. OBJECT

The purpose of the present document is to specify a simplified Method for the determination of different forms of nitrogen in fertilizers containing nitrogen only as nitric ammoniacal and urea nitrogen.

2. FIELD OF APPLICATION

The present Method can be used for all fertilizers mentioned in Annex I which contain exclusively nitric, ammoniacal or urea nitrogen.

3. PRINCIPLE

The following determinations are made on different portions of a single sample solution:

3.1. total soluble nitrogen:

3.1.1. in the absence of nitrates, by direct Kjeldahl digestion of the solution,

3.1.2. in the presence of nitrates, by Kjeldahl digestion of a portion of the solution after reduction by the Ulsch method; ammonia is determined in both cases as described in Method 2.1;

3.2. total soluble nitrogen except nitric nitrogen, by Kjeldahl digestion after elimination of nitric nitrogen in acid medium by means of ferrous sulphate; ammonia is determined as described in Method 2.1;

3.3. nitric nitrogen, by the difference between 3.1.2 and 3.2 or between total soluble nitrogen (3.1.2) and the sum of ammoniacal and urea nitrogen (3.4 + 3.5);

3.4. ammoniacal nitrogen, by cold distillation after slight alkalinization; the ammonia is obtained in a solution of sulphuric acid and determined as in Method 2.1;

3.5. urea nitrogen, either:

3.5.1. by transformation using urease, into ammonia, which is determined by titration with a standard solution of hydrochloric acid,

3.5.2. by gravimetry using xanhydrol: co-precipitated biuret can be taken with urea nitrogen with little error; its level is usually of small absolute value in compound fertilizers,

3.5.3. by difference, following the table:

>TABLE POSITION>

4. REAGENTS

Distilled or demineralized water.

4.1. Potassium sulphate for analysis

4.2. Iron for analysis, hydrogen reduced (the specified amount of iron must be able to reduce at least 50 mg of nitrate nitric N)

4.3. Potassium nitrate for analysis

4.4. Ammonium sulphate for analysis

4.5. Urea for analysis

4.6. Sulphuric acid solution: 0.2 mol/l

4.7. Concentrated sodium hydroxide solution: approximately 30 % (W/V) aqueous solution of NaOH, free of ammonia

4.8. Sodium or potassium hydroxide solution: 0.2 mol/l, free of carbonates

4.9. Sulphuric acid density (d20 = 1.84 g/ml)

4.10. Dilute hydrochloric acid: one volume of hydrochloric acid (d20 = 1.18 g/ml) plus one volume of water

4.11. Acetic acid: 96 to 100 %

4.12. Sulphuric acid solution containing approximately 30 % H2SO4 (W/V), free of ammonia

4.13. Ferrous sulphate: crystalline, FeSO4 . 7H2O

4.14. Titrated sulphuric acid solution: 0.1 mol/l

4.15. Octyl alcohol

4.16. Saturated potassium carbonate solution

4.17. Sodium or potassium hydroxide: 0.1 mol/l

4.18. Saturated barium hydroxide solution

4.19. Sodium carbonate solution: 10 % (W/V)

4.20. Hydrochloric acid: 2 mol/l

4.21. Hydrochloric acid solution: 0.1 mol/l

4.22. Urease solution

Make a suspension of 0.5 g of active urease in 100 ml of distilled water, using 0.1 mol/l hydrochloric acid (4.21), adjust the pH to 5.4, measured with pH meter.

4.23. Xanthydrol

5 % solution in ethanol or methanol (4.28) (do not use products giving a high proportion of insoluble material); the solution can be kept for three months in a carefully stoppered bottle in darkness.

4.24. Catalyst

Copper oxide (CuO): 0.3 to 0.4 g per determination, or an equivalent amount of copper sulphate pentahydrate (CuSO4 . 5H2O) of 0.95 to 1.25 g determination.

4.25. Pumice stone granules washed with hydrochloric acid and calcined

4.26. Indicator solutions

4.26.1. Mixed indicator

Solution A: Dissolve 1 g of methyl red in 37 ml of 0.1 mol/l sodium hydroxide solution and make up to one litre with water.

Solution B: Dissolve 1 g of methylene blue in water and make up to one litre.

Mix one volume of A with two volumes of B.

This indicator is violet in acid solution, grey in neutral solution and green in alkaline solution. Use 0.5 ml (10 drops) of this indicator.

4.26.2. Methyl red indicator solution

Dissolve 0.1 g of methyl red in 50 ml of 95 % ethanol. Make up to 100 ml with water and filter if necessary. Four or five drops of this indicator can be used instead of the previous one.

4.27. Indicator papers

Litmus, bromothymol blue (or other papers sensitive to pH 6 to 8).

4.28. Ethanol or methanol: 95 % (W/V)

5. APPARATUS

5.1. Distillation apparatus

See Method 2.1.

5.2. Apparatus for determination of ammoniacal nitrogen (7.5.1)

See Method 2.6.1 and Figure 6.

5.3. Apparatus for determination of urea nitrogen by the urease technique (7.6.1)

See Method 2.6.1 and Figure 7.

5.4. Rotary shaker (35 to 40 turns per minute)

5.5. A pH meter

5.6. Glassware:

- precision pipettes of 2, 5, 10, 20, 25, 50 and 100 ml,

- long-necked Kjeldahl flasks of 300 and 500 ml,

- graduated flasks of 100, 250, 500 and 1 000 ml,

- crucibles of sintered glass, pore diameter, 5 to 15 µm,

- mortar.

6. PREPARATION OF THE SAMPLE

See Method 1.

7. METHODS

7.1. Preparation of solution for analysis

Weigh out, to an accuracy of 1 mg, 10 g of sample, and transfer to a 500-ml graduated flask. Add 50 ml water and then 20 ml dilute hydrochloric acid (4.10). Shake. Allow to rest until any CO2 release comes to an end. Add 400 ml of water; shake for half an hour (5.4); make up to volume with water, homogenize, filter on a dry filter into a dry container.

7.2. Total nitrogen

7.2.1. In absence of nitrates

Pipette into a 300-ml Kjeldahl flask a portion of the filtrate (7.1), containing a maximum of 100 mg N. Add 15 ml of concentrated sulphuric acid (4.9), 0.4 g of copper oxide or 1.25 g of copper sulphate (4.24), and a few glass beads to control boiling. Heat moderately at first in order to initiate the reaction, then more strongly until the liquid becomes colourless or slightly greenish and white fumes unmistakably appear. After cooling, transfer the solution into the distillation flask, dilute to approximately 500 ml with water and add a few granules of pumice stone (4.25). Connect the flask to the distillation apparatus (5.1) and carry out the determination as described in 7.1.1.2, Method 2.6.1.

7.2.2. In the presence of nitrates

Pipette into 500-ml Erlenmeyer a portion of the filtrate (7.1) containing not mpore than 40 mg of nitric N. At this stage of the analysis, the total quantity of N is unimportant. Add 10 ml of 30 % sulphuric acid (4.12), 5 g of reduced iron (4.2), and immediately cover the Erlenmeyer with a watch glass. Heat gently until the reaction becomes strong but not violent. Stop heating and leave for at least three hours at ambient temperature. Transfer the liquid quantitatively to a 250-ml graduated flask, ignoring undissolved iron. Make up to the mark with water. Homogenize carefully. Pipette a portion containing a maximum of 100 mg N into a 300-ml Kjeldahl flask. Add 15 ml of concentrated sulphuric acid (4.9), 0.4 g of copper oxide or 1.25 g of copper sulphate (4.24), and some glass beads for the control of boiling. Heat moderately at first in order to initiate the reaction, then more strongly until the liquid becomes colourless or slightly greenish and white fumes unmistakably appear. After cooling, transfer the solution quantitatively to the distillation flask, dilute to approximately 500 ml with water, and add a few granules of pumice stone (4.25). Connect the flask to the distillation apparatus (5.1) and continue the determination as described in 7.1.1.2, Method 2.6.1.

7.2.3. Blank test

Carry out a blank test (omitting the sample) under the same conditions, and use the result in calculating the final result.

7.2.4. Expression of the result

>TABLE POSITION>

where

a =ml of titrated 0.2 mol/l sodium or potassium hydroxide solution (4.8), used in the blank test, carried out by placing 50 ml of titrated 0.2 mol/l sulphuric acid solution into the receiver of the apparatus (4.6),

A = ml of titrated 0.2 mol/l sodium or potassium hydroxide solution (4.8), used for the analysis,

M =mass of the test sample, in grams, present in the aliquot (7.2.1 or 7.2.2).

7.3. Total nitrogen excluding nitric N

7.3.1. Analysis

Pipette into a 300-ml Kjeldahl flask an aliquot of filtrate (7.1) containing not more than 50 mg N to be determined. Dilute to 100 ml with water, add 5 g of ferrous sulphate (4.13), 20 ml of concentrated sulphuric acid (4.9), and a few glass beads to control boiling. Heat moderately at first, then more strongly until white fumes appear. Continue the reaction for 15 minutes. Stop heating, introduce 0.4 g of copper oxide or 1.25 g of copper sulphate (4.24) as catalyst. Resume heating and maintain production of white fumes for 10 to 15 minutes. After cooling, transfer the contents of the Kjeldahl flask quantitatively to the distillation flask (5.1). Dilute to approximately 500 ml with water, and add a few granules of pumice stone (4.25). Connect the flask to the distillation apparatus and continue the determination as in 7.1.1.2, Method 2.6.1.

7.3.2. Blank test

See 7.2.3.

7.3.3. Expression of the result

>TABLE POSITION>

where

a = ml of titrated 0.2 mol/l sodium or potassium hydroxide solution (4.8), used in the blank test, carried out by pipetting 50 ml of titrated 0.2 mol/l sulphuric acid solution (4.6) into the receiver of the apparatus,

A = ml of titrated 0.2 mol/l sodium or potassium hydroxide solution, used for the analysis,

M = mass of the sample, expressed in grams, present in the aliquot used in the determination.

7.4. Nitric nitrogen

Is obtained by the difference between:

7.2.4 - (7.5.3 + 7.6.3)

or

7.2.4 - (7.5.3 + 7.6.5)

or

7.2.4 - (7.5.3 + 7.6.6)

7.5. Ammoniacal nitrogen

7.5.1. Analysis

Pipette into the dry flask of the apparatus (5.2) a portion of filtrate (7.1) containing a maximum of 20 mg of ammoniacal N. Connect up the apparatus. Pipette into the 300-ml Erlenmeyer exactly 50 ml of titrated 0.1 mol/l sulphuric acid solution (4.14) and an amount of distilled water so that the level of the liquid is approximately 5 cm above the opening of the intake tube. Introduce through the side neck of the reaction flask, distilled water so as to bring the volume to approximately 50 ml. Shake. In order to avoid the formation of froth on the introduction of the gaseous flow, add several drops of octyl alcohol (4.15). Add 50 ml of saturated potassium carbonate solution (4.16), and immediately begin to expel the ammonia thus released from the cold suspension. The intense air flow required for this purpose (flow rate of approximately three litres per minute) is previously purified by passage through washing flasks containing dilute sulphuric acid and dilute sodium hydroxide. Instead of using air under pressure, a vacuum may be used (water suction pump) provided that the connections between the apparatus are air tight.

The elimination of ammonia is generally completed after three hours.

However, it is desirable to make certain of this by changing the Erlenmeyer. When the process is finished, separate the Erlenmeyer from the apparatus, rinse the end of the intake tube and the Erlenmeyer walls with a little distilled water, and titrate the excess acid against a standard 0.1 mol/l sodium hydroxide solution (4.17).

7.5.2. Blank test

See 7.2.3.

7.5.3. Expression of the result

>TABLE POSITION>

where

a =ml of titrated 0.1 mol/l sodium or potassium hydroxide solution (4.17), used in the blank test, carried out by pipetting into the 300-ml Erlenmeyer of the apparatus (5.2) 50 ml of titrated 0.1 mol/l sulphuric acid solution (4.14),

A = ml of titrated 0.1 mol/l sodium or potassium hydroxide solution, used for the analysis (4.17),

M =mass of the sample, expressed in grams, present in the aliquot used for the analysis.

7.6. Urea nitrogen

7.6.1. Urease method

Pipette into a 500-ml graduated flask a portion of filtrate (7.1) containing not more than 250 mg of urea nitrogen. To precipitate phosphates, add a suitable quantity of saturated barium hydroxide solution (4.18) until further addition does not cause the production of more precipitate. Eliminate excess barium ions (and any dissolved calcium ions) by means of 10 % sodium carbonate solution (4.19). Allow to settle and check whether precipitation is complete. Make up to the mark, homogenize, and filter through a folder filter. Pipette 50 ml of filtrate into the 300-ml Erlenmeyer of the apparatus (5.3). Acidify with 2mol/l hydrochloric acid (4.20) to pH 3.0, measured by means of pH meter. Raise the pH to 5.4 by means of 0.1 mol/l sodium hydroxide (4.17). To avoid ammonia losses when hydrolysis by urease occurs, close the Erlenmeyer by means of a stopper attached to a dropping funnel and a small protective container holding exactly 2 ml of 0.1 mol/l hydrochloric acid solution (4.21). By way of the dropping funnel, introduce 20 ml of urease solution (4.22). Leave for one hour at 20 to 25 °C. Pipette 25 ml of the standard 0.1 mol/l hydrochloric acid solution (4.21) into the dropping funnel, allow to run into the solution, then rinse with a little water. Also transfer quantitatively the contents of the protective container to the solution held in the Erlenmeyer. Titrate the excess acid using the standard 0.1 mol/l sodium hydroxide solution (4.17), until a pH of 5.4 is obtained, measured on the pH meter.

Remarks

1. After precipitation by the barium hydroxide and sodium carbonate solutions, make up to the mark, filter, and neutralize as quickly as possible.

2. The titration may also be assessed using the indicator (4.26), although the change of colour is more difficult to observe.

7.6.2. Blank test

See 7.2.3.

7.6.3. Expression of the result

>TABLE POSITION>

where

a =ml of titrated 0.1 mol/l sodium or potassium hydroxide solution (4.17), used in the blank test, carried out in exactly the same conditions as the analysis,

A = ml of titrated 0.1 mol/l sodium or potassium hydroxide solution (4.17), used in the analysis,

M =sample mass, expressed in grams, present in the aliquot used for the analysis.

7.6.4. Gravimetric Method with xanthydrol

Pipette into a 100-ml beaker a portion of filtrate (7.1) containing not more than 20 mg of urea. Add 40 ml of acetic acid (4.11). Stir with a glass rod for one minute. Allow any precipitate to settle for five minutes. Filter, wash with a few millilitres of acetic acid (4.11). Add 10 ml of xanthydrol to the filtrate drop by drop (4.23), stirring continually with a glass rod. Leave it to settle until the precipitate appears, and at that juncture stir again for one to two minutes. Leave for one and a half hours. Filter on a glass filtration crucible, previously dried and weigh, using a slight reduction of pressure; wash three times with 5 ml of ethanol (4.28), without aiming to eliminate all the acetic acid. Transfer to oven and maintain at 130 °C for one hour (do not exceed 145 °C). Allow to cool in a desiccator and weigh.

7.6.5. Expression of the result

>TABLE POSITION>

where

m =mass of the precipitate obtained, in grams,

M = mass of the sample, in grams, present in the aliquot used in the determination.

Make the corrections for the blank. Biuret can generally be taken with urea nitrogen without large error, its level being of small absolute value in compound fertilizers.

7.6.6. Difference method

Urea N can also be calculated as indicated in the following table:

>TABLE POSITION>

8. VERIFICATION OF THE RESULT

Before each analysis, check the functioning of the apparatus and the correct application of the methods used with a standard solution containing the different forms of nitrogen in proportions similar to those in the sample. This standard solution is prepared from titrated solutions of potassium nitrate (4.3), ammonium sulphate (4.4) and urea (4.5).

Methods 3 PHOSPHORUS

Methods 3.1 EXTRACTIONS

Method 3.1.1 EXTRACTION OF PHOSPHORUS SOLUBLE IN MINERAL ACIDS

1. SCOPE

This document describes the procedure for the determination of phosphorus soluble in mineral acids.

2. FIELD OF APPLICATION

Applicable exclusively to the phosphate fertilizers listed in Annex I.

3. PRINCIPLE

Extraction of the phosphorus in the fertilizer with a mixture of nitric acid and sulphuric acid.

4. REAGENTS

Distilled or demineralized water.

4.1. Sulphuric acid (d20 = 1.84 g/ml).

4.2. Nitric acid (d20 = 1.40 g/ml).

5. EQUIPMENT

Standard laboratory equipment.

5.1. A Kjeldahl flask, with a capacity of at least 500 ml, or a 250-ml round-bottomed flask with a glass tube forming a reflux condenser.

5.2. A 500-ml graduated flask.

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Sample

Weigh, to the nearest 0.001 g, 2.5 g of the prepared sample and place it in a dry Kjeldahl flask.

7.2. Extraction

Add 15 ml of water and stir so as to suspend the substance. Add 20 ml of nitric acid (4.2) and carefully add 30 ml of sulphuric acid (4.1).

When the initial violent reaction has ceased, slowly bring the contents of the flask to boiling and boil for 30 minutes. Allow to cool and then carefully add with mixing about 150 ml of water. Continue boiling for 15 minutes.

Cool completely and transfer the liquid quantitatively to a 500-ml graduated flask. Make up to volume, mix and filter through a dry pleated filter, free from phosphates, discarding the first portion of the filtrate.

7.3. Determination

The determination of the phosphorus will be carried out by Method 3.2 on an aliquot part of the solution thus obtained.

Method 3.1.2 EXTRACTION OF THE PHOSPHORUS SOLUBLE IN 2 % FORMIC ACID (20 g per litre)

1. SCOPE

This document defines the procedure for the determination of phosphorus soluble in 2 % formic acid (20 g per litre).

2. FIELD OF APPLICATION

Soft natural phosphates exclusively.

3. PRINCIPLE

To differentiate between hard natural phosphates and soft natural phosphates, phosphorus soluble in formic acid is extracted under specific conditions.

4. REAGENTS

4.1. Formic acid, 2 % (20 g per litre)

Note

Make 82 ml of formic acid (concentration 98 to 100 %; d20 = 1.22g/ml) up to five litres with distilled water.

5. APPARATUS

Standard laboratory equipment.

5.1. A 500-ml graduated flask (e.g. Stohmann)

5.2. Rotary shaker (35 to 40 turns per minute)

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Sample

Weigh, to the nearest 0.001 g, 5 g of the prepared sample and place it in a dry 500-ml graduated Stohmann flask (5.1) with a wide neck.

7.2. Extraction

While continuously rotating the flask by hand, add the 2% formic acid at 20 ± 1 °C (4.1) until it is approximately 1 cm below the graduation mark and make up to the volume. Close the flask with a rubber stopper and shake for 30 minutes at 20 ± 2 °C on a rotary shaker (5.2).

Filter the solution through a dry pleated filter, free from phosphates, into a dry glass receptacle. Discard the first portion of the filtrate.

7.3. Determination

Determine the phosphorus according to Method 3.2 in an aliquot part of the completely clear filtrate.

Method 3.1.3 EXTRACTION OF PHOSPHORUS SOLUBLE IN 2 % CITRIC ACID (20 g per litre)

1. SCOPE

This document defines the procedure for the determination of phosphorus soluble in 2 % citric acid (20 g per litre).

2. FIELD OF APPLICATION

Only applicable to types of Basic slag (see Annex I A).

3. PRINCIPLE

Extraction of phosphorus from the fertilizer with a 2 % citric acid solution (20 g per litre) in given conditions.

4. REAGENTS

Distilled or demineralized water.

4.1. 2 % citric acid solution (20 g per litre), prepared from crystallized, citric acid (C6H8O7 . H2O)

Note

Verify the concentration of this citric acid solution by titrating 10 ml of the latter with a sodium hydroxide standard solution 0.1 mol/l, using phenolphtalein as an indicator.

If the solution is correct 28.55 ml of the standard solution should be used.

5. APPARATUS

5.1. Rotary shaker (35 to 40 turns per minute

6. PREPARATION OF THE SAMPLE

The analysis is carried out on the product as received after carefully mixing the original sample to ensure it is homogeneous. See Method 1.

7. PROCEDURE

7.1. Sample

Weigh, to the nearest 0.001 g, 5 g of the prepared sample and place it in a dry flask with a sufficiently wide neck, with a capacity of 600 ml, allowing the liquid to be shaken thoroughly.

7.2. Extraction

Add 500 ± 1 ml of the citric acid solution at 20 ± 1 °C. When adding the first millilitres of the reagent shake vigorously by hand to stop the formation of lumps and to prevent the substance sticking to the sides. Close the flask with a rubber stopper and shake it in the rotary shaker (5.1) for exactly 30 minutes at a temperature of 20 ± 2 °C.

Filter immediately through a dry pleated filter, free of phosphates, into a dry glass receiver and discard the first 20 ml of the filtrate. Continue the filtering until a sufficient quantity of filtrate is obtained to carry out the phosphorus determination.

7.3. Determination

The determination of the phosphorus extract will be carried out according to Method 3.2 on an aliquot part of the solution thus obtained.

Method 3.1.4 EXTRACTION OF PHOSPHORUS WHICH IS SOLUBLE IN NEUTRAL AMMONIUM CITRATE

1. SCOPE

This document defines the procedure for the determination of phosphorus soluble in neutral ammonium citrate.

2. FIELD OF APPLICATION

All fertilizers in respect of which solubility in neutral ammonium citrate is laid down (see Annex I).

3. PRINCIPLE

Extraction of phosphorus at a temperature of 65 °C using a neutral ammonium citrate solution (pH 7,0) under specific conditions.

4. REAGENT

Distilled or demineralized water.

4.1. Neutral ammonium citrate solution (pH 7,0)

This solution must contain per litre 185 g of crystallized citric acid and must have a specific gravity of 1.09 at 20 °C and a pH of 7,0.

The reagent is prepared as follows:

Dissolve 370 g of crystalline citric acid (C6H8O7 . H2O) in about 1.5 litres of water and make an approximately neutral solution by adding 345 ml of ammonium hydroxide solution (28 to 29 % of NH3). If the NH3 concentration is lower than 28 % add a correspondingly larger quantity of ammonium hydroxide solution and dilute the citric acid in correspondingly smaller quantities of water.

Cool and make exactly neutral by keeping the electrodes of a pH meter immersed in the solution. Add the ammonia, at 28 to 29 % of NH3, drop by drop, stirring continuously (with a mechanical stirrer) until obtaining exactly a pH of 7,0 at a temperature of 20 °C. At this point make up the volume to two litres and test the pH again. Keep the reagent in a closed container and check the pH at regular intervals.

5. APPARATUS

5.1. A two-litres beaker

5.2. A pH meter

5.3. A 200 or 250-ml Erlenmeyer flask

5.4. 500-ml graduated flasks and a 2,000-ml graduated flask

5.5. Water bath which can be set thermostatically at 65 °C, equipped with a suitable stirrer (see Figure 8)

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Sample

Transfer 1 or 3 g of the fertilizer to be analyzed (see Annex I A and B to the Regulation) into a 200 or 250-ml Erlenmeyer flask containing 100 ml of ammonium citrate solution previously heated to 65 °C.

7.2. Analysis of the solution

Stopper the Erlenmeyer flask and shake in order to suspend the fertilizer without forming lumps. Remove the stopper for an instant in order to balance the pressure and close the Erlenmeyer flask again. Place the flask in a water bath set to maintain the contents of the flask at exactly 65 °C and connect it to the stirrer (see Figure 8). During stirring, the level of the suspension in the flask must stay constantly below the level of the water in the water bath [30]. Mechanical stirring will be regulated so as to ensure complete suspension.

[30] If nomechanical stirrer is available, the flask may be shaken by hand every five minutes.

After stirring for exactly one hour, remove the Erlenmeyer flask from the water bath.

Cool immediately under running water to ambient temperature and, immediately, quantitatively transfer the contents from the Erlenmeyer flask into a graduated 500-ml flask with a jet of water (wash bottle). Make up the volume with water. Mix thoroughly. Filter through a dry pleated filter (medium speed phosphate free) into a dry container, discarding the first part of the filtrate (about 50 ml).

About 100 ml of clear filtrate will then be collected.

7.3. Determination

Determine the phosphorus of the extract thus obtained according to Method 3.2.

>REFERENCE TO A GRAPHIC>

Methods 3.1.5 EXTRACTION BY ALKALINE AMMONIUM CITRATE

Method 3.1.5.1 Extraction of soluble phosphorus according to Petermann at 65 °C

1. SCOPE

This document defines the procedure for the determination of soluble phosphorus in alkaline ammonium citrate.

2. FIELD OF APPLICATION

Exclusively to precipitated dihydrated dicalcium phosphate (CaHPO4 . 2H2O).

3. PRINCIPLE

Extraction of phosphorus at a temperature of 65 °C with an alkaline solution of ammonium citrate (Petermann) under specified conditions.

4. REAGENTS

Distilled water, or demineralized water having the same characteristics as distilled water.

4.1. Petermann's solution.

4.2. Characteristics

Citric acid (C6H8O7 . H2O): 173 g per litre.

Ammonia: 42 g per litre of ammoniacal nitrogen.

pH between 9.4 and 9.7.

Preparation from diammonium citrate

Dissolve 931 g of diammonium citrate (molecular mass 226.19) in about 3 500 ml of water, in a five-litre standard flask. Stand in a bath of running water, mix and cool and add in small amounts ammonia. For example, for d20 = 906 g/ml corresponding to a level of 20.81 % by mass of ammoniacal nitrogen, it is necessary to use 502 ml of ammonia solution. Adjust the temperature to 20 °C, make up to volume with distilled water. Mix.

Preparation from citric acid and ammonia

Dissolve 865 g of citric acid monohydrate in about 2 500 ml of distilled water in a container of about five-litres capacity. Place the container in an ice bath, and add in small amounts, shaking constantly, ammonia solution using a funnel, the stem of which is immersed in the citric acid solution. For example, for d20 = 906 g/ml corresponding to a level of 20.81 % by mass of ammoniacal nitrogen, it is necessary to add 1 114 ml of ammonia solution. Adjust the temperature to 20 °C, transfer to a five-litre standard flask, make up to the mark with distilled water and mix.

Check the ammoniacal nitrogen content as follows

Transfer 25 ml of the solution into a 250-ml standard flask and make up to volume with distilled water. Mix. Determine the ammoniacal content on 25 ml of this solution following Method 2.1. If the solution is correct, one must use 15 ml of 0.5 N H2SO4.

If the strength of ammoniacal nitrogen is greater than 42 g per litre, NH3 can be expelled by a stream of inert gas or by moderate heating to bring back the pH to 9.7. Carry out a second determination.

If the strength of ammoniacal nitrogen is less than 42 g per litre, it will be necessary to add a mass M of ammonia solution:

>TABLE POSITION>

If V is less than 25 ml, add it directly to the five-litre flask with a mass of V ( 0.173 g powdered citric acid.

If V is greater than 25 ml, it will be convenient to make a new litre of reagent in the following way.

Weigh 173 g of citric acid. Dissolve it in 500 ml of water. And, taking the precautions indicated, add not more than 225 + V ( 1 206 ml of ammonia solution which was used to prepare the five litres of reagent. Make up to volume with water. Mix.

Mix this litre with the 4 975 ml previously prepared.

5. APPARATUS

5.1. Water bath which can be maintained at a temperature of 65 ± 1 °C

5.2. A 500-ml graduated flask (e.g. Stohmann)

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Sample

Weigh, to the nearest 0.001 g, 1 g of the prepared sample and transfer to the 500-ml graduated flask (5.2).

7.2. Extraction

Add 200 ml of alkaline ammonium citrate solution (4.1). Stopper the flask and shake vigorously by hand to avoid the formation of lumps and to prevent any adherence of the substance to the sides.

Place the flask in the water bath set at 65 °C and shake every five minutes during the first half an hour. After each shaking, raise the stopper to equilibrate the pressure. The level of water in the water bath ought to be above the level of solution in the flask. Allow the flask to remain in the water bath a further hour at 65 °C and shake every 10 minutes. Remove the flask, cool to a temperature of about 20 °C, make up to a volume of 500 ml with water. Mix and filter through a dry fluted filter paper, free from phosphates, rejecting the first portion of filtrate.

7.3. Determination

The determination of phosphate extracted will be carried out by Method 3.2 on an aliquot part of the solution thus obtained.

Method 3.1.5.2 Extraction of the soluble phosphorus according to Petermann at ambient temperature

1. SCOPE

This document defines the procedure for the determination of phosphorus soluble in cold alkaline ammonium citrate.

2. FIELD OF APPLICATION

Disintegrated phosphates exclusively.

3. PRINCIPLE

Extraction of phosphorus at a temperature about 20 °C with an alkaline solution of ammonium citrate (Petermann's solution) in specific conditions.

4. REAGENT

See Method 3.1.5.1.

5. APPARATUS

5.1. Standard laboratory equipment, and a 250-ml graduated flask (e.g. Stohmann)

5.2. Rotary shaker (35 to 40 turns per minute)

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Sample

Weigh, to the nearest 0.001 g, 2.5 g of the prepared sample and place it in a 250-ml graduated flask (5.1).

7.2. Extraction

Add a little of Petermann's solution at 20 °C, shake very hard in order to stop the formation of lumps and to prevent any of the substance adhering to the side of the flask. Make up to the graduation mark with Petermann's solution and close the flask with a rubber stopper.

Shake for two hours in the rotary shaker (5.2). Filter immediately through a dry pleated filter, free from phosphate, into a dry container, discarding the first portion of the filtrate.

7.3. Determination

The phosphorus determination will be carried out by Method 3.2 on an aliquot part of the solution thus obtained.

Method 3.1.5.3 Extraction of the phosphorus soluble in Joulie's alkaline ammonium citrate

1. SCOPE

This document defines the procedure for the determination of phosphorus soluble in Joulie's alkaline ammonium citrate.

2. FIELD OF APPLICATION

All the straight and compound phosphate fertilizers, in which the phosphate occurs in an alumino-calcic form.

3. PRINCIPLE

Extraction by shaking vigorously with an alkaline solution of ammonium citrate of defined specification (and where appropriate in the presence of oxine) at about 20 °C.

4. REAGENTS

Destilled or demineralized water.

4.1. Joulie's alkaline solution of ammonium citrate.

This solution contains 400 g of citric acid and 153 g of NH3 per litre. Its free ammonia content is approximately 55 g per litre. It can be prepared by one of the methods described below.

4.1.1. In a one-litre graduated flask, dissolve 400 g of citric acid (C6H8O7 . H2O) in approximately 600 ml of ammonia (d20 = 0.925g/ml i.e. 200 g of NH3 per litre). The citric acid is added successively in quantities of 50 to 80 g maintaining the temperature below 50 °C. Make up the volume to one litre with ammonia.

4.1.2. In a one-litre graduated flask, of dissolve 432 g of dibasic ammonium citrate (C6H14N2O7) in 300 ml of water. Add 440 ml of ammonia (d20 = 0.925 g/ml). Make the volume up to one litre with water.

Note

Verification of the total ammonia content.

Take a 10-ml sample of the citrate solution and place it in a 250-ml flask. Make up the volume with distilled water. Determine the ammoniacal nitrogen content on 25 ml of this solution according to Method 2.1.

1 ml of H2SO4 0.5 mol/l = 0.008516 g of NH3

In these conditions, the reagent is considered to be correct when the number of millilitres found upon titration lies between 17.7 and 18 ml.

If this is not so add 4.25 ml of ammonia (d20 = 0.925 g/l) per 0.1 ml below 18 ml indicated above.

4.2. Powdered 8-hydroxyquinoline (oxine)

5. APPARATUS

5.1. Standard laboratory equipment and small mortar in glass or porcelain with pestle

5.2. 500-ml graduated flasks

5.3. A 1 000-ml graduated flask

5.4. Rotary shaker (35 to 40 turns per minute)

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Sample

Weigh, to the nearest 0.0005 g, 1 g of the prepared sample and place in a small mortar. Add about 10 drops of citrate (4.1) to moisten it and break it up very carefully with the pestle.

7.2. Extraction

Add 20 ml of ammonium citrate (4.1) and mix to a paste, leave it to settle for about one minute.

Decant the liquid into a 500-ml graduated flask, straining off particles which might have escaped the preceding moist disintegration. Add 20 ml of citrate solution (4.1) to the residue, grind as above and decant the liquid into the graduated flask. Repeat the process four times, so that by the end of the fifth time all the product can be poured into the flask. The total quantity of citrate used for these processes must be approximately 100 ml.

Rinse the pestle and mortar above the graduated flask with 40 ml of distilled water.

The stoppered flask is shaken for three hours on the rotary shaker (5.4).

Leave the flask standing for 15 to 16 hours, shake it again under same conditions for three hours. The temperature during the whole process is kept at 20 ± 2 °C.

Make up to the graduation mark with distilled water. Filter through a dry filter, discard the first portion of the filtrate and collect the clear filtrate in a dry flask.

7.3. Determination

The estimation of the extracted phosphorus will be carried out according to Method 3.2 on an aliquot part of the solution thus obtained.

8. APPENDIX

The use of oxine makes it possible to apply this Method to fertilizers containing magnesium. This use is recommended when the ratio of magnesium and phosphoric anhydride contents is higher than 0.03 (Mg/P2O5 ( 0.03). If this is the case, add 3 g of oxine to the moistened sample for analysis. The use of oxine in the absence of magnesium is not, moreover, likely to interfere subsequently with the determination. In the known absence of magnesium it is, however, possible not to use oxine.

Method 3.1.6 EXTRACTION OF WATER SOLUBLE PHOSPHORUS

1. SCOPE

This document defines the procedure for the determination of water soluble phosphorus.

2. FIELD OF APPLICATION

All fertilizers, including compound fertilizers, where water soluble phosphorus is to be determined.

3. PRINCIPLE

Extraction in water by shaking under specific conditions.

4. REAGENT

Distilled or demineralized water.

5. APPARATUS

5.1. A 500-ml graduated flask (e.g. Stohmann)

5.2. Rotary shaker (35 to 40 turns per minute)

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Sample

Weigh, to the nearest 0.001 g, 5 g of the prepared sample and place it in a 500-ml graduated flask (5.1).

7.2. Extraction

Add to the flask 450 ml of water, the temperature of which must be between 20 and 25 °C.

Shake in the rotary shaker (5.2) for 30 minutes.

Then make up to the mark with water, mix thoroughly by shaking and filter through a dry pleated filter, free of phosphate, into a dry container.

7.3. Determination

The estimation of phosphorus will be carried out on an aliquot part of the solution thus obtained by Method 3.2.

Method 3.2 DETERMINATION OF EXTRACTED PHOSPHORUS (Gravimetric Method using quinoline phosphomolybdate)

1. SCOPE

This document defines the procedure for the determination of phosphorus in the extracts from fertilizers.

2. FIELD OF APPLICATION

The Method is applicable to all extracts of fertilizers [31] for the determination of the different forms of phosphorus.

[31] Phosphorus soluble in mineral acids, water soluble phosphorus, phosphorus soluble in solutions of ammonium citrate, phosphorus soluble in 2 % citric acid and phosphorus soluble in 2 % formic acid.

3. PRINCIPLE

After possible hydrolysis, phosphorus is precipitated in an acid media in the form of quinoline phosphomolybdate.

After filtering and washing, the precipitate is dried at 250 °C and weighed.

In the above mentioned conditions no interfering action is exerted by the compounds likely to be found in the solution (mineral and organic acids, ammonium ions, soluble silicates, etc.) if a reagent based on sodium molybdate or ammonium molybdate is used in the precipitation.

4. REAGENTS

Distilled or demineralized water.

4.1. Concentrated nitric acid (d20 = 1.40 g/ml)

4.2. Preparation of reagent

4.2.1. Preparation of the reagent based on sodium molybdate

Solution A: Dissolve 70 g of sodium molybdate dihydrate in 100 ml of distilled water.

Solution B: Dissolve 60 g of citric acid monhydrate in 100 ml of distilled water and add 85 ml concentrated nitric acid (4.1).

Solution C: Stir solution A into solution B to obtain solution C.

Solution D:To 50 ml of distilled water, add 35 ml of concentrated nitric acid (4.1), then 5 ml of freshly distilled quinoline. Add this solution to solution C, mix thoroughly and leave standing overnight in the dark. After this make up to 500 ml with distilled water, mix again, and filter through a sintered glass funnel (5.6).

4.2.2. Preparation of the reagent based on ammonium molybdate

Solution A: In 300 ml of distilled water, dissolve 100 g of ammonium molybdate while heating gently and stirring from time to time.

Solution B: Dissolve 120 g of citric acid monohydrate in 200 ml of distilled water, add 170 ml of concentrated nitric acid (4.1).

Solution C: Add 10 ml of freshly distilled quinoline to 70 ml of concentrated nitric acid (4.1).

Solution D: Slowly pour, stirring well, solution A into solution B. After thoroughly mixing add solution C to this mixture and make up to one litre. Leave standing for two days in a dark place and filter through a sintered glass funnel (5.6).

The reagents 4.2.1 and 4.2.2 can be used in the same way; both must be kept in the dark in stoppered polyethylene bottles.

5. APPARATUS

5.1. Standard laboratory equipment and a 500-ml Erlenmeyer flask with a wide neck

5.2. Graduated pipettes of 10, 25 and 50 ml

5.3. Filter crucible with porosity of 5 to 20 µ

5.4. Buchner flask

5.5. Drying oven regulated at 250 ± 10 °C

5.6. Sintered glass funnel with porosity of 5 to 20 µ

6. PROCEDURE

6.1. Treatment of the solution

With a pipette, take an aliquot part of fertilizer extract (see Table 2) containing about 0.01 g of P2O5 and put it in a 500-ml Erlenmeyer flask. Add 15 ml of concentrated nitric acid [32] (4.1) and dilute with water to about 100 ml.

[32] 21 ml when the solution to be precipitated contains more than 15 ml of citrate solution (neutral citrate, Petermann or Joulie alkaline citrate).

Table 2 Determining the aliquot parts of the phosphate solutions

>TABLE POSITION>

6.2. Hydrolysis

If the presence of metaphosphates, pyrophosphates or polyphosphates is suspected in the solution, hydrolysis is carried out as follows.

Bring the contents of the Erlenmeyer flask to the boil slowly and keep at this temperature until hydrolysis is completed (this usually takes one hour). Care must be taken to avoid losses by splashing and excessive evaporation which could reduce the initial volume by more than half, by fitting a reflux condenser. After Hydrolysis make up to the initial volume with distilled water.

6.3. Weighing the crucible

Dry the filter crucible (5.3) for at least 15 minutes in the drying oven set at 250 ± 10 °C. Weigh it after it has been cooled in a desiccator.

6.4. Precipitation

The acid solution contained in the Erlenmeyer flask is heated until it begins to boil then precipitation of the quinoline phosphomolybdate is started by adding 40 ml of the precipitating reagent (reagent 4.2.1 or 4.2.2) [33] drop by drop, stirring continuously. Place the Erlenmeyer flask in a steam bath, leave it there for 15 minutes, shaking it from time to time. The solution can be filtered immediately or after it has cooled down.

[33] To precipitate phosphate solutions containing more than 15 ml of citrate solution (neutral, Petermann or Joulie) which have been acidified with 21 ml of concentrated nitric acid (see footnote to 6.1) use 80 ml of the precipitating reagent.

6.5. Filtering and washing

Filter the solution under vacuum by decantation. Wash the precipitate in the Erlenmeyer flask with 30 ml of water. Decant and filter the solution. Repeat this process five times. Quantitatively transfer the rest of the precipitate into the crucible washing it with water. Wash four times with 20 ml of water, allowing the liquid to drain from the crucible before each addition. Dry the precipitate thoroughly.

6.6. Drying and weighing

Wipe the outside of the crucible with a filter paper. Place this crucible in a drying oven and keep it there until its mass remains constant, at a temperature of 250 °C (5.5) (usually 15 minutes); leave it to cool in the desiccator at ambient temperature and weigh rapidly.

6.7. Blank test

For each series of determinations, carry out a blank test using only the reagents and solvents in the proportions used in the extraction (citrate solution, etc.) and allow for them in the calculation of the final result.

6.8. Verification

Carry out the determination using an aliquot part of a potassium dihydrogen phosphate solution containing 0.01 g of P2O5.

7. EXPRESSION OF THE RESULT

If the samples for analysis and dilutions shown in Table 2 are used, the following formula applies:

% P in the fertilizer = (A - a) ( F'

or

% P2O5 in the fertilizer = (A - a) ( F

where

A = mass, in grams, of the quinoline phosphomolybdate,

a = mass, in grams, of the quinoline phosphomolybdate obtained in the blank test,

F and F' = factors given in the last two columns of Table 2.

With samples for analysis and dilutions which differ from those of Table 2, the following formula applies:

>TABLE POSITION>

or

>TABLE POSITION>

where

f and f' = conversion factors of quinoline phosphomolybdate into P2O5 = 0.032074, (f) or into P = 0.013984 (f'),

D = dilution factor,

M = mass, in grams, of the sample analyzed.

Method 4 POTASSIUM

Method 4.1 DETERMINATION OF THE WATER SOLUBLE POTASSIUM CONTENT

1. SCOPE

This document defines the procedure for the determination of water soluble potassium.

2. FIELD OF APPLICATION

All the potassium fertilizers listed in Annex I.

3. PRINCIPLE

The potassium in the sample to be analyzed is dissolved in water. After eliminating or fixing the substances which might interfere with the quantitative determination, the potassium is precipitated in a slightly alkaline medium in the form of potassium tetraphenylborate.

4. REAGENTS

Distilled or demineralized water.

4.1. Formaldehyde

Clear formaldehyde solution at 25 to 35 %.

4.2. Potassium chloride for analysis

4.3. Sodium hydroxide solution: 10 mol/l

Care should be taken to ensure that only potassium free sodium hydroxide is used.

4.4. Indicator solution

Dissolve 0.5 g of phenolphthalein in ethanol at 90 % and make the volume up to 100 ml.

4.5. EDTA solution

Dissolve 4 g of the dihydrated disodium salt of ethylenediaminetetraacetic acid in water in a 100-ml graduated flask. Make up the volume and mix.

Store the reagent in a plastic container.

4.6. STPB solution

Dissolve 32.5 g of sodium tetraphenylborate in 480 ml of water add 2 ml of the sodium hydroxide solution (4.3) and 20 ml of a magnesium chloride solution (100 g of MgCl2 . 6H2O per litre).

Stir for 15 minutes and filter through a fine, ashless filter.

Store this reagent in a plastic container.

4.7. Liquid for washing

Dilute 20 ml of the STPB solution (4.6) to 1 000 ml with water.

4.8. Bromine water

Saturated bromine solution in water.

5. APPARATUS

5.1. 1 000-ml graduated flasks

5.2. A 250-ml beaker

5.3. Filter crucibles with a porosity of 5 to 20 µ

5.4. Oven regulated at 120 ± 10 °C

5.5. Desiccator

6. PREPARATION OF THE SAMPLE

See Method 1.

In the case of potassium salts the sample must be ground fine enough in order that a representative sample is obtained for analysis. For these products Method 1 (6) (a) must be used.

7. PROCEDURE

7.1. Sample

Weigh, to the nearest 0.001 g, 10 g of the prepared sample (5 g for potassium salts containing more than 50 % of potassium oxide). Place this test sample in a 600-ml beaker with approximately 400 ml of water.

Bring to the boil and allow it to boil for 30 minutes. Cool, transfer quantitatively into a 1 000 ml graduated flask, make up the volume, mix and filter into a dry receiver. Discard the first 50 ml of the filtrate (see 7.6, note on procedure).

7.2. Preparation of the aliquot part for precipitation

Transfer by pipette an aliquot part of the filtrate containing 25 to 50 mg of potassium (see Table 3) and place it in a 250-ml beaker. If required make up to 50 ml with water.

To remove any interference, add 10 ml of the EDTA solution (4.5), several drops of the phenolphtalein solution (4.4) and stir in, drop by drop, sodium hydroxide solution (4.3) until it turns red, then finally add a few more drops of sodium hydroxide to ensure an excess (usually 1 ml of sodium hydroxide is sufficient to neutralize the sample and ensure an excess).

To eliminate most of the ammonia [see 7.6 (b), note on procedure] boil gently for 15 minutes.

If necessary add water to make the volume up to 60 ml.

Bring the solution to the boil, remove the beaker from the heat and add 10 ml of formaldehyde (4.1). Add several drops of phenolphtalein and, if necessary, some more sodium hydroxide, until a distinct red colour appears. Cover the beaker with a watch glass and place it on a steam bath for 15 minutes.

7.3. Weighing the crucible

Dry the filter crucible (see 5 "Apparatus") to constant mass (about 15 minutes) in the oven at 120 °C (5.4).

Allow the crucible to cool in a desiccator and then weigh it.

7.4. Precipitation

Remove the beaker from the steam bath, stir in drop by drop 10 ml of the STPB solution (4.6). This addition takes about two minutes. Wait for at least 10 minutes before filtering.

7.5. Filtering and washing

Filter under vacuum into the weighed crucible, rinse the beaker with the liquid for washing (4.7), wash the precipitate three times with the liquid for washing (60 ml in all of the liquid for washing) and twice with 5 to 10 ml of water.

Dry the precipitate thoroughly.

7.6. Drying and weighing

Wipe the outside of the crucible with a filter paper. Place the crucible with its contents in the oven for one and a half hours at a temperature of 120 °C. Allow the crucible to cool in a desiccator to ambient temperature and weigh rapidly.

Note on procedure

a) If the filtrate is dark in colour, transfer by pipette, an aliquot part containing at the most 100 mg of K2O and place in a 100-ml graduated flask, add bromine water and bring to the boil to eliminate any surplus bromine. After cooling make up the volume, filter and quantitatively determine the potassium in an aliquot part of the filtrate.

b) Where there is little or no ammoniacal nitrogen present, there is no need to boil for 15 minutes.

7.7. Aliquot parts to be taken as samples and conversion factors

Table 3 For Method 4

>TABLE POSITION>

7.8. Blank test

For each series of determinations, carry out a blank test using only the reagents in the proportions used in the analysis and allow for this when calculating the final result.

7.9. Control test

In order to obtain a control for the Method of analysis, carry out a determination on an aliquot part of an aqueous solution of potassium chloride, containing at the most 40 mg of K2O.

8. EXPRESSION OF THE RESULT

It one uses the samples for analysis and the dilutions shown in Table 3, the formula to apply is the following:

% K2O in the fertilizer = (A - a) ( F

or

% K in the fertilizer = (A - a) ( F'

where

A = mass, in grams, of the precipitate from the sample,

a = mass, in grams, of the precipitate from the blank,

F and F' = factors (see Table 3).

With samples and dilutions which differ from those shown in Table 3, use the following formula:

>TABLE POSITION>

or

>TABLE POSITION>

where

f = conversion factor, KTPB into K2O = 0.1314,

f' = conversion factor, KTPB into K = 0.109,

D = dilution factor,

M = mass, in grams, of sample for analysis.

Method 5

No item

Method 6 CHLORINE

Method 6.1 DETERMINATION OF CHLORIDES IN THE ABSENCE OF ORGANIC MATERIAL

1. SCOPE

This document defines the procedure for the determination of chloride, in the absence of organic material.

2. FIELD OF APPLICATION

All fertilizers which are free from organic material.

3. PRINCIPLE

The chlorides, dissolved in water, are precipitated in an acid medium by an excess of standard solution of silver nitrate. The excess is titrated with a solution of ammonium thiocyanate in the presence of ferric ammonium sulphate (Volhard's method).

4. REAGENTS

Distilled or demineralized water, free from chlorides.

4.1. Nitrobenzene or diethyl ether

4.2. Nitric acid: 10 mol/l

4.3. Indicator solution

Dissolve 40 g of ferric ammonium sulphate Fe2(SO4)3 . (NH4)2SO4 . 24H2O, in water and make up to one litre.

4.4. Silver nitrate standard solution: 0.1 mol/l

Preparation

Since this salt is hygroscopic and cannot be dried without risk of decomposition, it is advisable to weigh out approximately 9 g, dissolve in water and make up the volume to one litre. Adjust to 0.1 mol/l strength by titration of AgNO3 0.1 mol/l.

5. APPARATUS

5.1. Rotary shaker (35 to 40 turns per minute)

5.2. Burettes

5.3. A 500-ml graduated flask

5.4. Conical (Erlenmeyer) flask of 250 ml

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Sample and preparation of the solution

Place 5 g of the sample, weighed out to nearest 0.001 g, in a 500-ml graduated flask and add 450 ml of water. Mix for half an hour on the shaker (5.1); make up to 500 ml with distilled water; mix and filter into a beaker.

7.2. Determination

Take an aliquot part of the filtrate containing not more than 0.150 g of chloride. For example 25 ml (0.25 g), 50 ml (0.5 g) or 100 ml (1 g). If the sample taken is smaller than 50 ml it is necessary to make up the volume to 50 ml with distilled water.

Add 5 ml of nitric acid 10 mol/l (4.2), 20 ml of indicator solution (4.3), and two drops of ammonium thiocyanate standard solution (a sample of this latter reagent is taken with a burette adjusted to zero for this purpose).

With a burette then add silver nitrate standard solution (4.4) until there is an excess of 2 to 5 ml. Add 5 ml of nitrobenzene or 5 ml of diethyl ether (4.1) and shake well to agglomerate the precipitate. Titrate the excess silver nitrate with ammonium thiocyanate 0.1 mol/l (4.5) until a red-brown colour appears which remains after the flask has been shaken slightly.

Note

Nitrobenzene or diethyl ether (but above all nitrobenzene) prevents the silver chloride from reacting with thiocyanate ions. Thus a clear colour change is obtained.

7.3. Blank test

Carry out a blank test (omitting the sample) under the same conditions and allow for it when calculating the final result.

7.4. Control test

Before carrying out the estimations check the accuracy of the Method by using an aliquot part of a freshly prepared solution of potassium chloride, such that this part contains a known quantity in the order of 100 mg of chloride.

8. EXPRESSION OF THE RESULT

Express the result of the analysis as a percentage of chloride contained in the sample as it has been received for analysis.

Calculate the percentage of chloride (Cl) with the formula:

>TABLE POSITION>

where

Vz = number of millilitres of silver nitrate 0.1 mol/l,

Vcz = number of millilitres of silver nitrate 0.1 N, used in the blank test,

Va = number of millilitres of ammonium thiocyanate 0.1 mol/l,

Vca = number of millilitres of ammonium thiocyanate 0.1 mol/l, used in the blank test,

M = mass, in grams, of the sample taken (7.2).

Methods 7 FINENESS OF GRINDING

Method 7.1 DETERMINATION OF FINENESS OF GRINDING (dry procedure)

1. SCOPE

This document defines the dry procedure, for the determination of the fineness of grinding.

2. FIELD OF APPLICATION

All EC type fertilizers in which requirements are given of fineness of grinding using 0.630 and 0.160 mm sieves.

3. PRINCIPLE

By mechanical sieve shaking, the quantities of product with a granule size greater than 0.630 mm and those with a granule size between 0.160 and 0.630 mm are determined, and the percentage of fineness of grinding is calculated.

4. APPARATUS

4.1. Mechanical sieve shaker

4.2. Sieves with apertures of 0.160 and 0.630 mm respectively of standard ranges (20 cm diameter and 5 cm high)

5. PROCEDURE

Weigh, to the nearest 0.05 g, 50 g of the substance. Assemble the two sieves and the collecting container on the shaker (4.1), the sieve with the larger apertures being placed on top. Place the sample for analysis on the top. Sieve for 10 minutes and remove the part collected on the bottom. Start the apparatus up again and after one minute check that the amount collected on the bottom during this time is not more than 250 mg. Repeat the process (for one minute each time) until the amount collected is less than 250 mg. Weigh the residual material on both sieves separately.

6. EXPRESSION OF THE RESULT

% fineness of the sample shown by the sieve, with 0.630 mm apertures = (50 - M1) ( 2

% fineness of the sample shown by the sieve, with 0.160 mm apertures = [50 - (M1 + M2)] ( 2

where

M1 = mass, in grams, of residue on the sieve, with 0.630 mm apertures,

M2 = mass, in grams, of residue on the sieve, with 0.160 mm apertures.

The reject from the sieve, with 0.630 mm apertures having been already eliminated.

The results of these calculations are rounded up to the nearest unit.

Method 7.2 DETERMINATION OF THE FINENESS OF GRINDING OF SOFT NATURAL PHOSPHATES

1. SCOPE

This Method is for determining the fineness of grinding of soft natural phosphates.

2. FIELD OF APPLICATION

Soft natural phosphates.

3. PRINCIPLE

For samples of fine particle size, agglomeration may occur thus making dry sieving difficult. For this reason, wet sieving is normally used.

4. REAGENTS

Sodium hexametaphosphate solution: 1 %.

5. APPARATUS

5.1. Sieves with apertures of 0.063 and 0.125 mm respectively of standard ranges (diameter 20 cm and height 5 cm); collecting containers

5.2. Glass funnel of 20 cm diameter mounted on a stand

5.3. 250-ml beakers

5.4. Drying oven

6. METHOD OF ANALYSIS

6.1. Sampling

Weigh, to the nearest 0.05 g, 50 g of the substance. Wash both sides of the sieve with water and place the sieve with 0.125 mm apertures above the 0.063 mm sieve.

6.2. Procedure

Place the sample for analysis on the top sieve. Sieve under a small jet of cold water (tap water can be used) until the water is practically clear when it passes through. Care should be taken to ensure that the flow of water is such that the lower sieve never fills with water.

When the residue on the top sieve seems to remain more or less constant, remove this sieve, and place, in the meanwhile on a collecting container.

Continue the wet sieving through the lower sieve for a few minutes, until the water passing through is nearly clear.

Replace the 0.125 mm sieve over the 0.063 mm sieve. Transfer any deposit from the collecting container to the top sieve and begin sieving again under a small jet of water until this water becomes almost clear once more.

Quantitatively transfer each of the residues into a different beaker by means of the funnel. Suspend each residue by filling the beakers with water. Leave to stand for about one minute, decant, as much water as possible.

Place the beakers in the drying oven at 150 °C for two hours.

Allow them to cool, detach the residues with a brush and weigh them.

7. EXPRESSION OF THE RESULT

The results of the calculations are rounded up to the nearest unit.

% fineness shown by the residue left on the 0.125 mm sieve = (50 - M1) ( 2

% fineness shown by the residue left on the 0.063 sieve = [50 - (M1 + M2)] ( 2

where

M1 = mass, in grams, of the residue on the 0.125 mm sieve,

M2 = mass, in grams, of the residue on the 0.063 mm sieve.

8. REMARKS

If the presence of lumps is observed after sieving the analysis should be carried out again in the following way.

Slowly pour 50 g of the sample into a one-litre flask containing 500 ml of the sodium hexametaphosphate solution stirring continuously. Stopper the flask and shake vigorously by hand to break up the lumps. Transfer the whole suspension into the top sieve and wash the flask thoroughly. Continue the analysis as described in 6.2.

Methods 8 SECONDARY NUTRIENTS

Method 8.1 EXTRACTION OF TOTAL CALCIUM, TOTAL MAGNESIUM, TOTAL SODIUM AND TOTAL SULPHUR IN THE FORM OF SULPHATES

1. SCOPE

This document defines the procedure for extracting total calcium, total magnesium and total sodium, and for extracting the total sulphur present in the form of sulphates, so that the same extract may be used for the determination of each nutrient required.

2. FIELD OF APPLICATION

This Method applies to EC fertilizers, for which a declaration of the total calcium, total magnesium, total sodium, and total sulphur in the form of sulphates is provided for in this Regulation.

3. PRINCIPLE

Solubilization by boiling in dilute hydrochloric acid.

4. REAGENTS

4.1. Diluted hydrochloric acid

One volume of hydrochloric acid (d20 = 1,18 g/ml) plus one volume of water.

5. APPARATUS

Electric hot plate with adjustable temperature.

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Test sample

Calcium, magnesium, sodium and sulphur in the form of sulphates are extracted from a test sample of five grams weighed to within one milligram.

However, when the fertilizer contains more than 15 % of sulphur (S) i.e. 37,5 % SO3, and more than 18,8 % of calcium (Ca) i.e. 26,3 % CaO, the extraction of calcium and sulphur is carried out on a test sample of one gram, weighed to within one milligram. Place the test sample in a 600 millilitre beaker.

7.2. Preparation of the solution

Add approximately 400 millilitres of water and, taking care when the sample contains a significant quantity of carbonates, 50 millilitres of dilute hydrochloric acid (4.1) a small amount at a time. Bring to the boil and maintain for 30 minutes. Allow to cool, stirring occasionally. Decant quantitatively into a 500 millilitre graduated flask. Make up to volume with water, and mix. Pass through a dry filter into a dry container, discarding the initial portion. The extract must be completely transparent. Stopper if the filtrate is not used immediately.

Method 8.2 EXTRACTION OF TOTAL SULPHUR PRESENT IN VARIOUS FORMS

1. SCOPE

This document defines the procedure for extracting the total sulphur contained in fertilizers in elemental form and/or in other chemical combinations.

2. FIELD OF APPLICATION

This Method applies to EEC fertilizers for which a declaration of the total sulphur present in various forms (elemental, thiosulphate, sulphite, sulphate) is provided for in this Regulation.

3. PRINCIPLE

Elemental sulphur is converted in an alkaline medium into polysulphides and thiosulphate; these, together with any sulphites which may be present, are then oxidized with hydrogen peroxide. The various forms of sulphur are thus converted into sulphate which is determined by precipitation of barium sulphate (Method 8.9).

4. REAGENTS

4.1. Diluted hydrochloric acid:

One volume of hydrochloric acid (d = 1,18) plus one volume of water.

4.2. Sodium hydroxide solution, NaOH, 30 % minimum (d = 1,33)

4.3. Hydrogen peroxide solution, 30 % w/w

4.4. Aqueous solution of barium chloride BaCl2, 2H2O, 122 grams per litre

5. APPARATUS

Electric hot plate with adjustable temperature.

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Test sample

Weigh out to within one milligram a quantity of fertilizer containing between 80 and 350 milligrams of sulphur (S) or 200 and 875 milligrams of SO3.

As a rule (where S < 15 %), weigh out 2,5 grams. Place the test sample in a 400 millilitre beaker.

7.2. Oxidation

Add 20 millilitres of sodium hydroxide solution (4.2) and 20 millilitres of water. Cover with a watch glass. Boil for five minutes on the hot plate (5.1). Remove from the hot plate. Using a jet of hot water, collect the sulphur sticking to the sides of the beaker and boil for 20 minutes. Leave to cool.

Add 2 millilitres increments of hydrogen peroxide (4.3) until no reaction is observed. Six to eight ml of hydrogen peroxide will be necessary. Allow oxidation to continue for one hour, then bring to the boil for half an hour. Leave to cool.

7.3. Preparation of the solution to be analyzed

Add approximately 50 millilitres of water and 50 millilitres of the hydrochloric acid solution (4.1).

- If the level of sulphur (S) is less than 5 %: filter into a 600 millilitre beaker. Wash the residue on the filter several times with cold water. After washing, check for the absence of sulphate in the last drops of the filtrate using a barium chloride solution (4.4). The filtrate must be perfectly clear. Sulphate is determined on the whole of the filtrate in accordance with Method 8.9.

- If the level of sulphur (S) is at above 5 %: transfer quantitatively into a 250 millilitre volumetric flask, make up to volume with water and mix. Filter through a dry filter into a dry container; the filtrate must be completely clear. Stopper if the solution is not to be used immediately. Determine sulphates on an aliquot of this solution by precipitation in the form of barium sulphate (Method 8.9).

Method 8.3 EXTRACTION OF WATER-SOLUBLE CALCIUM, MAGNESIUM, SODIUM AND SULPHUR (in the form of sulphates)

1. SCOPE

This document defines the procedure for extracting water-soluble calcium, magnesium, sodium and sulphur (in the form of sulphates), so that the same extract can be used to determine each nutrient required.

2. FIELD OF APPLICATION

This Method applies solely to fertilizers for which a declaration of the water soluble calcium, magnesium, sodium and sulphur (in the form of the sulphates) is provided for in Annex I.

3. PRINCIPLE

The nutrients are solubilized in boiling water.

4. REAGENTS

Distilled or demineralized water of equivalent quality.

5. APPARATUS

Electric hot plate with adjustable temperature.

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Test sample

a) Where fertilizers contain no sulphur or where they contain, at the same time,nomore than 3 % of the sulphur (S) i.e. 7,5 % SO3 and no more than 4 % of calcium (Ca) i.e. 5,6 % CaO, weigh out five grams of fertilizer to within one milligram.

b) Where fertilizers contain more than 3 % of sulphur (S) and more than 4 % of calcium (Ca), weigh out one gram of fertilizer to within one milligram.

Place the test sample in a 600 millilitre beaker.

7.2. Preparation of the solution

Add approximately 400 millilitres of water and boil for 30 minutes. Allow to cool, stirring occasionally, and decant quantitatively into a 500 millilitre graduated flask. Make up to volume with water and mix.

Filter through a dry filter into a dry container. Discard the initial portions of the filtrate. The filtrate must be completely transparent.

Stopper if the solution is not to be used immediately.

Method 8.4 EXTRACTION OF WATER-SOLUBLE SULPHUR WHERE THE SULPHUR IS IN VARIOUS FORMS

1. SCOPE

This document defines the procedure for extracting the water-soluble sulphur contained in fertilizers in various forms.

2. FIELD OF APPLICATION

This Method applies to fertilizers for which a declaration of the water-soluble sulphur trioxide is provided for in Annex I.

3. PRINCIPLE

The sulphur is dissolved in cold water and converted into sulphate by oxidation with hydrogen peroxide in an alkaline medium.

4. REAGENTS

4.1. Diluted hydrochloric acid

One volume of hydrochloric acid (d20 = 1,18 g/ml) plus one volume of water.

4.2. Sodium hydroxide solution containing at least 30 % NaOH (d20 = 1,33 g/ml)

4.3. Hydrogen peroxide solution, 30 % w/w

5. APPARATUS

5.1. 500 millilitre graduated Stohmann flask

5.2. Rotary shaker, 30 to 40 turns per minute

5.3. Electric hot plate with adjustable temperature

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Test sample

a) Where fertilizers contain a maximum of 3 % of sulphur (S) i.e. 7,5 % SO3, together with a maximum of 4 % of calcium (Ca) i.e. 5,6 % CaO, weigh out 5 grams of fertilizer to within one milligram.

b) Where fertilizers contain more than 3 % of sulphur (S) and more than 4 % of calcium (Ca), weigh out one gram of fertilizer to within one milligram.

Place the test sample in a 500 millilitre flask (5.1).

7.2. Preparation of the solution

Add approximately 400 millilitres of water. Stopper. Shake (5.2) for 30 minutes. Make up to volume with water and mix. Pass through a dry filter into a dry container. Stopper if the solution is not to be used immediately.

7.3. Oxidation of the aliquot portion to be analyzed

Take an aliquot portion of the extraction solution not exceeding 50 millilitres and, if possible, containing between 20 and 100 milligrams of sulphur (S).

Make up the volume to 50 millilitres with water, if necessary. Add three millilitres of sodium hydroxide solution (4.2) and two millilitres of hydrogen peroxide solution (4.3). Cover with a watch glass and boil gently for one hour on the hot plate (5.3). Keep adding one millilitre increments of hydrogen peroxide solution for as long as the reaction continues (maximum quantity five millilitres).

Then leave to cool. Remove the watch glass and wash the underside into the beaker. Add approximately 20 millilitres of dilute hydrochloric acid (4.1). Make up to approximately 300 millilitres with water.

Determine the content of sulphates on the whole of the oxidized solution in accordance with Method 8.9.

Method 8.5 EXTRACTION AND DETERMINATION OF ELEMENTAL SULPHUR

WARNING

This Method of analysis involves the use of carbon disulphide (CS2). Special safety measures must therefore be taken, in particular with regard to:

- the storage of CS2,

- protective equipment for staff,

- occupational hygiene,

- prevention of fires and explosions,

- disposal of the reagent.

This Method requires a highly skilled staff and a suitably equipped laboratory.

1. SCOPE

This defines the procedure for extracting and determining the elemental sulphur contained in fertilizers.

2. FIELD OF APPLICATION

This Method applies to EC fertilizers for which a declaration of the total sulphur in elemental form is provided for in Annex I.

3. PRINCIPLE

After the removal of soluble compounds, elemental sulphur is extracted by using carbon disulphide, followed by gravimetric determination of the sulphur extracted.

4. REAGENTS

Carbon disulphide.

5. APPARATUS

5.1. 100 millilitre extraction flask with ground glass stopper

5.2. Soxhlet apparatus, with the appropriate filter elements

5.3. Vacuum rotary evaporator

5.4. Electric oven, fan assisted, set at 90 ± 2 °C

5.5. Porcelain petri dishes, five to seven centimeters in diameter, not exceeding five centimeters in height

5.6. Electric hot plate with adjustable temperature

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Test sample

Weigh out five to ten grams of the sample to an accuracy of one milligram and place in the thimble of the Soxhlet apparatus (5.2).

7.2. Extraction of the sulphur

Wash thoroughly the contents with hot water to remove all soluble compounds. Dry in the oven at 90 °C (5.4) for at least one hour. Place the filter in the Soxhlet apparatus (5.2).

Place a few glass beads in the flask of the apparatus (5.1) and weigh (P0), then add 50 millilitres of carbon disulphide (4.1).

Connect the apparatus and leave the elemental sulphur to be extracted for six hours. Switch off the heat and, after cooling, disconnect the flask. Connect the flask to the rotary evaporator (5.3) and evaporate until the contents of the flask have solidified in a spongy mass.

Dry the flask in the oven at 90 °C (5.4) (generally one hour is necessary) until a constant mass is obtained (P1).

7.3. Determination of the purity of the elemental sulphur

Certain substances may have been extracted by the carbon disulphide at the same time as the elemental sulphur. The purity of the elemental sulphur is determined as follows:

homogenize the contents of the flask as thoroughly as possible, and remove two or three grams, weighed to an accuracy of one milligram (n). Place in the Petri dish (5.5). Weigh dish and contents together (P2). Place on the hot plate (5.6) set at a temperature not exceeding 220 °C so as not to cause combustion of the sulphur. Continue sublimation for three or four hours until a constant mass is obtained (P3).

Note

For some fertilizers, it may not be necessary to determine how pure the sulphur is. In this case, omit step 7.2.

8. EXPRESSION OF RESULTS

The percentage elemental sulphur (S) content of the fertilizer is as follows:

>TABLE POSITION>

Where

m = the mass of the test sample of fertilizer in grams,

P0 = the mass of the Soxhlet flask in grams,

P1 = the mass of the Soxhlet flask and the impure sulphur after drying,

n = the mass of the impure sulphur to be purified in grams,

P2 = the mass of the Petri dish,

P3 = the mass of the Petri dish after sublimation of the sulphuring.

Method 8.6 MANGANIMETRIC DETERMINATION OF EXTRACTED CALCIUM FOLLOWING PRECIPITATION IN THE FORM OF OXALATE

1. SCOPE

This document defines the procedure for determining the calcium in fertilizer extracts.

2. FIELD OF APPLICATION

This Method applies to EC fertilizers for which a declaration of the total and/or water-soluble calcium is provided for in Annex I.

3. PRINCIPLE

Precipitation of the calcium contained in an aliquot of the extraction solution in the form of an oxalate, which is determined by titration using potassium permanganate.

4. REAGENTS

4.1. Diluted hydrochloric acid

One volume of hydrochloric acid (d20 = 1,18g/ml) and one volume of water.

4.2. 1:10 dilute sulphuric acid

One volume of sulphuric acid (d20 = 1,84 g/ml) in ten volumes of water.

4.3. 1:1 dilute ammonia solution

One volume of ammonia (d20 = 0,88 g/ml) and one volume of water.

4.4. Saturated solution of ammonia oxalate [(NH4)2 C2O4 H2O] at ambient temperature (approximately 40 grams per litre)

4.5. Citric acid solution, 30 % (m/v)

4.6. Ammonium chloride solution, 5 % (m/v)

4.7. Solution of bromothymol blue in ethanol, at 95 %, 0,1 % (m/v)

4.8. Solution of bromocresol green in ethanol, at 95 %, 0,04 % (m/v)

4.9. Standard solution of potassium permanganate, 0,02 mol/l

5. APPARATUS

5.1. Filter crucible with 5 to 20 µ porosity sintered glass

5.2. Hot water bath

6. PREPARATION OF THE ALIQUOT TO BE ANALYZED

Using a pipette, take an aliquot portion of the extraction solution obtained by Method 8.1 or 8.3, containing between 15 and 50 milligrams of Ca (= 21 to 70 milligrams of CaO). Let the volume of this aliquot be v2. Pour into a 400 millilitre beaker. If necessary, neutralize (turning of indicator (4.7) from green to blue) with a few drops of the ammonia solution (4.3).

Add one millilitre of the citric acid solution (4.5) and five millilitres of ammonium chloride solution (4.6).

7. PRECIPITATION OF THE CALCIUM OXALATE

Add approximately 100 millilitres of water. Bring to the boil, add eight to ten drops of indicator solution (4.8) and, slowly, 50 millilitres of a hot ammonium oxalate solution (4.4). If a precipitate forms, dissolve by adding a few drops of hydrochloric acid (4.1). Neutralize very slowly with ammonia solution (4.3) while stirring continuously to a pH of 4.4 to 4.6 (turning of indicator (4.8) from green to blue). Place the beaker in a boiling hot water bath (5.2) for approximately 30 minutes.

Remove the beaker from the bath, leave standing for an hour and filter into the crucible (5.1).

8. TITRATION OF THE OXALATE PRECIPITATE

Wash the beaker and crucible until the excess ammonium oxalate has been completely removed (this can be checked by the absence of chloride in the washing water). Place the crucible in the 400 millilitre beaker and dissolve the precipitate with 50 millilitres of hot sulphuric acid (4.2). Add water to the beaker in order to obtain a volume of approximately 100 millilitres. Bring to a temperature of 70 to 80 °C and titrate drop by drop with a permanganate solution (4.9) until the pink colour lasts for a minute. Let this volume be n.

9. EXPRESSION OF RESULTS

The calcium (Ca) content of the fertilizer is as follows:

>REFERENCE TO A GRAPHIC>

Where

n = the number of millilitres of permanganate used,

m = the mass of the test sample in grams,

v2 = the aliquot volume in millilitres,

v1 = the volume of the extraction solution in millilitres,

t = the concentration of the permanganate solution in moles per litre.

CaO (%) = Ca (%) × 1,400

Method 8.7 DETERMINATION OF MAGNESIUM BY ATOMIC ABSORPTION SPECTROMETRY

1. SCOPE

This document defines the procedure for determining the magnesium in fertilizer extracts.

2. FIELD OF APPLICATION

This Method applies to EC fertilizer extracts obtained by methods 8.1 and 8.3, for which a declaration of the total magnesium and/or water soluble magnesium is required, with the exception of the following fertilizers listed in Annex I D relating to secondary nutrients:

- type 4 (kieserite),

- type 5 (magnesium sulphate) and type 5.1 (magnesium sulphate solution),

and with the exception of the following fertilizer listed in Annex I A 3 relating to potassic fertilizers:

- type 7 (kieserite with potassium sulphate)

to which Method 8.8 applies.

The Method set out below applies to all fertilizer extracts containing elements in quantities that might interfere with the complexometric determination of magnesium.

3. PRINCIPLE

Determination of magnesium by atomic absorption spectrometry after appropriate dilution of the extract.

4. REAGENTS

4.1. Hydrochloric acid, 1 mol/l solution

4.2. Hydrochloric acid, 0,5 mol/l solution

4.3. Standard solution of magnesium, 1,00 milligrams per millilitre

4.3.1. Dissolve 1.013 grams of magnesium sulphate (MgSO4, 7H2O) in the 0,5 mol/l hydrochloric acid solution (4.2)

4.3.2. Weigh out 1.658 grams of magnesium oxide (MgO), previously calcined to remove all traces of carbonation. Place in a beaker with 100 millilitres of water and 120 millilitres of 1 mol/l hydrochloric acid (4.1). When it has dissolved, decant quantitatively into a 1 000 millilitre graduated flask. Make up the volume by adding and mix

or

4.3.3. Commercial standard solution

The laboratory is responsible for testing such solutions.

4.4. Strontium chloride solution

Dissolve 75 grams of strontium chloride (SrCl2 6H2O) in a hydrochloric acid solution (4.2) and make up to 500 millilitres with the same acid solution.

5. APPARATUS

Spectrometer fitted for atomic absorption, with a magnesium lamp, set at 285,2 nm.

Air-acetylene flame.

6. PREPARATION OF THE SAMPLE

See methods 8.1 and 8.3.

7. PROCEDURE

7.1. If the fertilizer has a declared magnesium (Mg) content of more than 6 % (i.e. 10 % as MgO), take 25 millilitres (V1) of the extraction solution (6). Transfer into a 100 millilitre graduated flask, and make up to volume with water and mix. The dilution factor is D1 = 100/V1

7.2. Using a pipette, take 10 millilitres of the extraction solution (6) or the solution (7.1). Transfer into a 200 millilitre graduated flask. Make up to volume with the 0,5 mol/l hydrochloric acid solution (4.2) and mix. The dilution factor is 200/10

7.3. Dilute this solution (7.2) with the 0,5 mol/l hydrochloric acid solution (4.2) so as to obtain a concentration in the optimum working field of the spectrometer (5.1). V2 is the volume of the sample in 100 millilitres. The dilution factor is D2 = 100/V2

The final solution should contain 10 % v/v of the strontium chloride solution (4.4).

7.4. Preparation of blank solution

Prepare a blank solution by repeating the whole procedure from the extraction (Method 8.1 or 8.3), omitting only the test sample of fertilizer.

7.5. Preparation of calibration solutions

By diluting the standard solution (4.3) with the 0,5 mol/l hydrochloric acid, prepared at least five calibration solutions of increasing concentration within the optimum measuring range of the apparatus (5.1).

These solutions should contain 10 % v/v of the strontium chloride solution (4.4).

7.6. Measurement

Set up the spectrometer (5.1) at a wavelength of 285,2 nm.

Spray, successively, the calibration solutions (7.5), the sample solution (7.3) and the blank solution (7.4), washing the instrument through with the solution to be measured next. Repeat this operation three times. Plot the calibration curve using the mean absorbancies of each of the calibrations (7.5) as the ordinates and the corresponding concentration of magnesium in µg/ml as the abscissae. Determine the concentration of magnesium in the sample (7.3), Xs and blank (7.4), Xb, by reference to the calibration curve.

8. EXPRESSION OF RESULTS

Calculate the amount of magnesium (Mg) or magnesium oxide (MgO) in the sample by reference to the calibration solutions and taking into consideration the blank.

The percentage of magnesium (Mg) in the fertilizer is equal to:

>TABLE POSITION>

Where

Xs = the concentration of the solution to be analyzed recorded on the calibration curve, in µg/ml.

Xb = the concentration of the blank solution as recorded on the calibration curve, in µg/ml.

D1 = the dilution factor when the solution is diluted (7.1).

- It is equal to four if 25 millilitres are taken.

- It is equal to one when the solution is not diluted.

D2 = the dilution factor is 7.3.

M = the mass of the test sample at the time of extraction.

- MgO (%) = Mg (%)/0,6

Method 8.8 DETERMINATION OF MAGNESIUM BY COMPLEXOMETRY

1. SCOPE

This document defines the procedure for the determination of magnesium in fertilizer extracts.

2. FIELD OF APPLICATION

This Method applies to the following EC fertilizer extracts for which the determination of total magnesium and/or water-soluble magnesium is provided for:

- fertilizers listed in Annex I: straight nitrogenous fertilizers, type 1b + 1c (calcium magnesium nitrate), type 7 (magnesium sulphonitrate), type 8 (nitrogenous fertilizers with magnesium) and straight potassic fertilizers, type 2 (enriched kainite), type 4 (potassium chloride containing magnesium), type 6 (potassium sulphate containing magnesium salt),

- fertilizers listed in the Annex I D relating to secondary nutrients.

3. PRINCIPLE

The magnesium is solubilized by methods 8.1 and/or 8.3. First titration: with EDTA of Ca and Mg in the presence of Eriochrome black T. Second titration: with EDTA of Ca in the presence of calcein or of calcone carbonic acid. Determination of magnesium by difference.

4. REAGENTS

4.1. Standard 0,05 mol/l solution of magnesium:

4.1.1. Dissolve 1,232 grams of magnesium sulphate (MgSO4 7H2O) in the 0,5 mol/l hydrochloric acid solution (4.11) and make up to 100 millilitres with the same acid

or

4.1.2. Weigh out 2,016 grams of magnesium oxide, previously calcined to remove all traces of carbonation. Place it in a beaker with 100 millilitres of water

Stir in approximately 120 millilitres of approximately 1 mol/l hydrochloric acid (4.12).

After dissolution, transfer quantitatively into a graduated 1 000 millilitre flask. Make up to volume and mix.

One millilitre of these solutions should contain 1,216 milligrams of Mg (= 2,016 milligrams of MgO).

The laboratory is responsible for testing the strength of this standard solution.

4.2. 0,05 molar solution of EDTA

Weigh out 18,61 grams of the dihydrated disodium salt of ethylenediaminetetraacetic (C10H14N2Na2O8,2H2O), place it in a 1 000 millilitre beaker and dissolve in 600 to 800 millilitres of water. Transfer the solution quantitatively into a graduated 1 000 millilitre flask. Make up the volume and mix. Check this solution with the standard solution (4.1) by taking a sample of 20 millilitres of the latter and by titration according to the analytical procedure described at (7.2).

One millilitre of the EDTA solution should correspond to 1,216 milligrams of Mg (= 2,016 milligrams of MgO) and to 2,004 milligrams of Ca (= 2,804 milligrams CaO) (see remarks 10.1 and 10.6).

4.3. 0,05 molar standard solution of calcium

Weigh out 5,004 grams of dry calcium carbonate. Place it in a beaker with 100 millilitres of water. Progressively stir in 120 millilitres of approximately 1 mol/l hydrochloric acid (4.12).

Bring to the boil in order to drive off the carbon dioxide, cool, transfer quantitatively into a graduated one-litre flask, make up the volume with water and mix. Check this solution against the EDTA solution (4.2) following analytical procedure (7.3). One millilitre of this solution should contain 2,004 milligrams of Ca (=2,804 milligrams of CaO) and should correspond to one millilitre of the 0,05 molar EDTA solution (4.2).

4.4. Calcein indicator

Carefully mix in a mortar one gram of calcein with 100 grams of sodium chloride. Use 10 milligrams of this mixture. The indicator changes from green to orange. Titration must be carried out until an orange is obtained which is free from green tinges.

4.5. Calcon carbonic acid indicator

Dissolve 400 milligrams of calcon carbonic in 100 millilitres of methanol. This solution may only be kept for approximately four weeks. Use three drops of this solution. The indicator changes from red to blue. Titration must be carried out until a blue is obtained which is free from red tinges.

4.6. Eriochrome black-T indicator

Dissolve 300 milligrams of Eriochrome black-T in a mixture of 25 millilitres of propanol-1 and 15 millilitres of triethanolamine. This solution may only be kept for approximately four weeks. Use three drops of this solution. This indicator turns from red to blue and titration must be carried out until a blue is obtained which is free from red tinges. It changes colour only when magnesium is present. If necessary add one millilitre of the standard solution (4.1).

When both calcium and magnesium are present the EDTA first forms a complex with the calcium and then with the magnesium. In that case two elements are determined concurrently.

4.7. Potassium cyanide solution

Aqueous solution of KCN at 2 %. (Do not pipette by mouth and see 10.7).

4.8. Solution of potassium hydroxide and potassium cyanide

Dissolve 280 grams of KOH and 66 grams of KCN in water, make up the volume to one litre and mix.

4.9. pH 10,5 buffer solution

In a 500 millilitre graduated flask, dissolve 33 grams of ammonium chloride in 200 millilitres of water, add 250 millilitres of ammonia (d20 = 0,91 g/ml) make up the volume with water and mix. Test the pH of the solution regularly.

4.10. Diluted hydrochloric acid: one volume of hydrochloric acid (d20 = 1,18 g/ml) plus one volume of water

4.11. Hydrochloric acid solution approximately 0,5 mol/l

4.12. Hydrochloric acid solution approximately 1 mol/l

4.13. Sodium hydroxide solution 5 mol/l

5. APPARATUS

5.1. Magnetic or mechanical stirrer

5.2. pH meter

6. CONTROL TEST

Carry out a determination on aliquot parts of solutions (4.1 and 4.3) such that the Ca/Mg ratio is approximately equal to that of the solution to be analyzed. To this end take (a) millilitres of Mg standard solution (4.3) and (b-a) millilitres of standard solution (4.1). (a) and (b) are the numbers of millilitre EDTA solution used in the two titrations performed on the solution to be analyzed. This procedure is correct only if the solutions of EDTA, calcium and magnesium are exactly equivalent. If this is not the case, it is necessary to make corrections.

7. PREPARATION OF THE SOLUTION TO BE ANALYZED

See methods 8.1 and 8.3.

8. DETERMINATION

8.1. Aliquot samples to be taken

The aliquot part will as far as possible contain between 9 and 18 milligrams of magnesium (= 15 to 30 milligrams of MgO).

8.2. Titration in the presence of Eriochrome black-T

Pipette an aliquot part (8.1) of the solution to be analyzed into a 400 millilitre beaker. Neutralize the surplus acid with the 5 mol/l sodium hydroxide solution (4.12) using the pH meter. Dilute with water to approximately 100 millilitres. Add 5 millilitres of the buffer solution (4.9). The pH measured by the meter must be 10,5 ± 0,1. Add 2 millilitres of the potassium cyanide solution (4.7) and three drops of the Eriochrome black-T indicator (4.6). Titrate with the EDTA solution (4.2). Stirring gently with the stirrer (5.1) (see 10.2, 10.3 and 10.4). Let "b" be the number of millilitres of 0,05 mol/l EDTA solution.

8.3. Titration in the presence of calcein or of calcon carbonic acid

Pipette an aliquot part of the solution to be analyzed equal to that taken from the above titration and place it in a 400 millilitre beaker. Neutralize the surplus acid with the 5 mol/l sodium hydroxide solution (4.13) using the pH meter. Dilute with water to about 100 millilitres. Add 10 millilitres of the KOH/KCN solution (4.8) and the indicator (4.4 or 4.5). Stirring gently with the stirrer (5.1) titrate with the EDTA solution (4.2) (see 10.2, 10.3 and 10.4). Let "a" be the number of millilitres of 0,05 mol/l EDTA solution.

9. EXPRESSION OF THE RESULTS

For the EEC fertilizers to which the Method is applicable (5 grams of fertilizer in 500 millilitres of extract), the percentage content of the fertilizer is:

>TABLE POSITION>

Where

a = the number of millilitres of 0,05 mol/l EDTA solution used for the titration in the presence of calcein or calcon carbonic acid,

b = the number of millilitres of 0,05 mol/l EDTA solution used for the titration in the presence of Eriochrome black-T,

M = the mass of the sample present in the aliquot part taken (in grams),

T = 0,2016 × mol/l of the EDTA solution/0,05 (see 4.2),

T' = 0,1216 × mol/l of the EDTA solution/0,05 (see 4.2).

10. REMARKS

10.1. The stoichiometric EDTA-metal ratio in the complexometric analyses is always 1:1 whatever the valency of the metal and in spite of the fact that EDTA is quadrivalent. The EDTA titration solution and the standard solutions will therefore be molar and not normal

10.2. Complexometric indicators are often sensitive to air. The solution may lose colour during titration. In this case, one or two drops of indicator must be added. This is true particularly in the case of eriochrome black and calcon carbonic acid

10.3. The metal-indicator complexes are often relatively stable and it may take some time for the colour to change. The last drops of EDTA must therefore be added slowly and a drop of 0,05 mol/l solution of magnesium (4.1) or calcium (4.3) added to ensure that the colour change has not already taken place. This is particularly true in the case of the eriochrome-magnesium complex

10.4. The turning of the indicator must be observed not vertically, but horizontally across the solution and the beaker must be placed against a white background in a well-lit position. The turning of the indicator may also be observed easily by placing the beaker on frosted glass lit moderately from below (25 watt lamp)

10.5. This analysis requires a certain amount of experience. The task will involve, inter alia, observing the colour changes of standard solutions 4.1 and 4.3. It is recommended that the determinations be carried out by the same laboratory chemist

10.6. If an EDTA solution of guaranteed strength is used (Titrisol, Normex, for example) this may simplify the control of the equivalence of standard solutions 4.1, 4.2 and 4.3

10.7. The solutions containing potassium cyanide must not be poured down the sink until the cyanide has been converted into a harmless compound, for example, by oxidization with sodium hydrohclorite following alkalization

Method 8.9 DETERMINATION OF SULPHATES

1. SCOPE

This document defines the procedure for determining the sulphur present in fertilizer extracts in the form of sulphates.

2. FIELD OF APPLICATION

This Method applies to the determination of sulphates present in the extractions performed in methods 8.1, 8.2, 8.3 and 8.4.

3. PRINCIPLE

Gravimetric determination as barium sulphate.

4. REAGENTS

4.1. Diluted hydrochloric acid

One volume of hydrochloric acid (d20 = 1,18 g/ml) and one volume of water.

4.2. Barium chloride solution BaCl22H2O:122 grams per litre

4.3. Silver nitrate solution: 5 grams per litre

5. APPARATUS

5.1. Porcelain crucibles

5.2. Hot water bath

5.3. Drying oven set at 105 °C ± 1 °C

5.4. Electric oven set at 800 °C ± 50 °C

6. PROCEDURE

6.1. Sampling of the solution

Pipette an aliquot part of one of the extraction solutions indicated at 2 containing between 20 and 100 milligrams of S or 50 and 250 milligrams of SO3.

Place this aliquot in a beaker of suitable capacity. Add 20 millilitres of dilute hydrochloric acid (4.1). Make up to about 300 millilitres with water.

6.2. Preparation of the precipitate

Bring the solution to the boil. Add, drop by drop, about 20 millilitres of the barium chloride solution (4.2) while stirring the solution vigorously. Boil for a few minutes.

Place the beaker, covered with a watch glass, in a boiling hot water bath (5.2) for an hour. Then leave standing hot (± 60 °C) until the supernatant liquor is clear. Decant the clear solution through a slow filtration ash-free filter. Wash the precipitate several times with hot water. Continue to wash the precipitate on the filter until the filtrate is chloride free. This can be checked by using silver nitrate solution (4.3).

6.3. Incineration and weighing of the precipitate

Place the filter paper and precipitate in a porcelain crucible (5.1) previously weighed to the nearest 0,1 milligrams. Dry in the oven (5.3) and ash at approximately 800 °C for half an hour (5.4). Allow to cool in a desiccator and weigh to within 0,1 milligrams.

7. EXPRESSION OF THE RESULTS

One milligram of barium sulphate corresponds to 0,137 milligrams of S or to 0,343 milligrams of SO3.

The percentage S content of the fertilizer is as follows:

>TABLE POSITION>

SO3 (%) = S (%) × 2,5

Where

w = the mass of the barium sulphate precipitate in milligrams,

v1 = the volume of the extraction solution in millilitres,

v2 = the aliquot volume in millilitres,

m = the mass of the test sample in grams.

Method 8.10 DETERMINATION OF THE SODIUM EXTRACTED

1. SCOPE

This document defines the procedure for determining the sodium in fertilizer extracts.

2. FIELD OF APPLICATION

This Method applies to EC fertilizers for which a declaration of the sodium is provided for in Annex I.

3. PRINCIPLE

Following suitable dilution of the extract obtained via Method 8.1 and/or 8.3, the sodium content of the solution is determined by flame-emission spectrometry.

4. REAGENTS

4.1. Diluted hydrochloric acid

One volume of hydrochloric acid for analysis (d20 = 1,18 g/ml) plus one volume of water.

4.2. Aluminium nitrate Al(NO3)3, 9H2O

4.3. Caesium chloride, CsCl

4.4. Anhydrous sodium chloride, NaCl

4.5. Caesium chloride and aluminium nitrate solution

Dissolve in water 50 grams of caesium chloride (4.3) and 250 grams of aluminium nitrate (4.2) in a 1 000 millilitre graduated flask. Make up to volume with water and mix.

4.6. Standard sodium solution of one milligram/millilitre of Na

Dissolve in water 2,542 grams of sodium chloride (4.4) in a 1 000 millilitre graduated flask. Add 10 millilitres of hydrochloric acid (4.1). Make up to volume with water and mix.

5. APPARATUS

Spectrometer equipped for flame emission, set at 589,3 nm.

6. CALIBRATION SOLUTIONS

6.1. Place 10 millilitres of standard solution (4.6) in a 250 millilitre graduated flask. Make up to volume and mix. Concentration of solution: 40 µg/ml of Na

6.2. Place 0, 5, 10, 15, 20, 25 millilitres of the intermediate solution (6.1) in 100 millilitre graduated flasks. Add 10 millilitres of the solution (4.5). Make up to volume and mix. Concentration of solutions: 0, 2, 4, 6, 8, 10 µg/ml of Na

7. PREPARATION OF SOLUTIONS TO BE MEASURED

Depending upon the expected sodium content of the extraction solution as in Method 8.1 or 8.3 (five grams of fertilizer in 500 millilitres), carry out the dilutions in accordance with the following table:

>TABLE POSITION>

Make up the intermediate dilution with water. For the final dilution add ten millilitres of the solution (4.5) to the 100 millilitre graduated flask.

For a test sample of one gram multiply the volume of the final dilution (v4) by five.

8. DETERMINATION

Prepare the spectrometer (5.1) for the measurements at 589,3 nm. Calibrate the instrument by measuring the response of the calibration solutions (6.2). Then adjust the sensitivity of the instrument to use its entire scale when the most concentrated calibration solution is used. Then measure the response of the sample solution to be analyzed (7). Repeat this operation three times.

9. CALCULATION OF RESULTS

Draw a calibration curve by plotting the average response for each calibration solution along the ordinate and the corresponding concentrations, expressed in µg per millilitre on the abscissa. Determine from this the sodium concentration of the test solution. Calculate the quantity of sodium from the standard solutions taking account of the levels of dilution. Express the results as a percentage of the sample.

The percentage sodium (Na) content of the fertilizer is as follows:

>TABLE POSITION>

Na2O (%) = Na (%) × 1,348

Where

x = the concentration of the solution introduced into the spectrometer in µg/ml,

v1 = the volume of the extraction solution in millilitres,

v2 = the aliquot volume in the intermediate dilution in millilitres,

v3 = the volume of intermediate dilution in millilitres,

v4 = the aliquot volume in ml of the final dilution (to 100 millilitres),

m = the mass of the test sample in grams.

Methods 9 MICRO-NUTRIENTS at a concentration of less than or equal to 10%

Method 9.1 EXTRACTION OF TOTAL MICRO-NUTRIENTS

1. SCOPE

This Method defines the procedure for extracting the following micro-nutrients: total boron, total cobalt, total copper, total iron, total manganese, total molybdenum and total zinc. The aim is to carry out the minimum number of extractions, making use wherever possible of the same extract to determine the total level of each of the micro-nutrients listed above.

2. FIELD OF APPLICATION

This procedure concerns EC fertilizers covered by Annex I E containing one or more of the following micro-nutrients: boron, cobalt, copper, iron, manganese, molybdenum and zinc. It is applicable to each micro-nutrient the declared content of which is less than or equal to 10 %.

3. PRINCIPLE

Dissolution in boiling dilute hydrochloric acid.

Note

The extraction is empirical and may not be quantitative depending on the product or the other constituents of the fertilizer. In particular, in the case of certain manganese oxides, the quantity extracted may be substantially smaller than the total quantity of manganese which the product contains. It is the responsibility of the fertilizer manufacturers to ensure that the declared content actually corresponds to the quantity extracted under the conditions pertaining to the method.

4. REAGENTS

4.1. Dilute hydrochloric acid (HCl) solution, about 6 mol/l

Mix 1 volume of hydrochloric acid (d20 = 1,18 g/ml) with 1 volume of water.

4.2. Concentrated ammonia solution (NH4OH, d20 = 0,9 g/ml)

5. APPARATUS

Electric hotplate with variable temperature control.

Note

Where the boron content of an extract is to be determined, do not use borosilicate glassware. As the Method involves boiling, teflon or silica is preferable. Rinse the glassware thoroughly if it has been washed in detergents containing borates.

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Test sample

Take a quantity of fertilizer weighing between 2 and 10 g depending on the declared content of element in the product. The following table shall be used to obtain a final solution which, after appropriate dilution, will be within the measuring range for each method. Samples should be weighed to within 1 mg.

>TABLE POSITION>

Place the sample in a 250 ml beaker.

7.2. Preparation of the solution

If necessary moisten the sample with a little water, add 10 ml of dilute hydrochloric acid (4.1) per gram of fertilizer carefully, in small amounts, then add about 50 ml of water. Cover the beaker with a watch glass and mix. Bring to the boil on the hotplate and boil for 30 minutes. Allow to cool, stirring occasionally. Transfer quantitatively to a 250 or 500 ml volumetric flask (see Table). Make up to volume with water and mix thoroughly. Filter through a dry filter into a dry container. Discard the first portion. The extract must be perfectly clear.

It is recommended that the determination be carried out without delay on aliquot portions of the clear filtrate, if not the containers should be stoppered.

Remark

Extracts in which the boron content has to be determined: Adjust the pH to between 4 and 6 with concentrated ammonia (4.2).

8. DETERMINATION

The determination of each micro-nutrient is to be carried out on the aliquot portions indicated in the Method for each individual micro-nutrient.

If necessary, remove organic chelating or complexing substances from an aliquot portion of the extract by using Method 9.3. In the case of determination by atomic absorption spectrometry, such removal may not be necessary.

Method 9.2 EXTRACTION OF WATER-SOLUBLE MICRO-NUTRIENTS

1. SCOPE

This Method defines the procedure for extracting water-soluble forms of the following micro-nutrients: boron, cobalt, copper, iron, manganese, molybdenum and zinc. The aim is to carry out the minimum number of extractions, making use wherever possible of the same extract to determine the level of each of the micro-nutrients listed above.

2. FIELD OF APPLICATION

This procedure concerns EC fertilizers covered by Annex I containing one or more of the following micro-nutrients: boron, cobalt, copper, iron, manganese, molybdenum and zinc. It is applicable to each micro-nutrient the declared content of which is less than or equal to 10 %.

3. PRINCIPLE

The micro-nutrients are extracted by shaking the fertilizer in water at 20 °C ± 2 °C.

Note

The extraction is empirical and may or may not be quantitative.

4. REAGENTS

4.1. Dilute hydrochloric acid (HCl) solution, about 6 mol/l

Mix 1 volume of hydrochloric acid (d20 = 1,18 g/ml) with 1 volume of water.

5. APPARATUS

5.1. Rotary shaker set at about 35 to 40 rpm

5.2. pH-meter

Note

Where the boron content of the extract is to be determined, do not use borosilicate glassware. Teflon or silica is preferable for this extraction. Rinse the glassware thoroughly if it has been washed in detergents containing borates.

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Test sample

Take a quantity of fertilizer weighing between 2 and 10 g depending on the declared content of the element in the product. The following table shall be used to obtain a final solution which, after appropriate dilution, will be within the measuring range for each method. The samples should be weighed to within 1 mg.

>TABLE POSITION>

Place the sample in a 250 or 500 ml flask (according to the Table).

7.2. Preparation of the solution

Add about 200 ml of water to the 250 ml flask or 400 ml of water to the 500 ml flask.

Stopper the flask well. Shake vigorously by hand to disperse the sample, then place the flask on the shaker and shake for 30 minutes.

Make up to volume with water and mix thoroughly.

7.3. Preparation of the test solution

Filter immediately into a clean, dry flask. Stopper the flask. Carry out the determination immediately after filtering.

Note

If the filtrate gradually becomes cloudy, make another extraction following 7.1 and 7.2 in a flask of volume Ve. Filter into a calibrated flask of volume W which has previously been dried and has received 5,00 ml of dilute hydrochloric acid (4.1). Stop the filtration at the exact moment when the calibration mark is reached. Mix thoroughly.

Under these conditions the value of V in the expression of results is:

V = Ve × W / (W - 5)

The dilutions in the expression of results depend on this value of V.

8. DETERMINATION

The determination of each micro-nutrient is carried out on the aliquot portions indicated in the Method for each individual micro-nutrient.

If necessary, remove organic chelating or complexing substances from an aliquot portion by using Method 9.3. In the case of determination by atomic absorption spectrometry, such removal may not be necessary.

Method 9.3 REMOVAL OF ORGANIC COMPOUNDS FROM FERTILIZER EXTRACTS

1. SCOPE

This Method defines a procedure for removing organic compounds from fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to analyzing samples of fertilizers extracted by Methods 9.1 and 9.2 for which a declaration of total and/or water-soluble element is required by Annex I E to this Regulation.

Note

The presence of small quantities of organic matter usually does not affect determination by means of atomic absorption spectrometry.

3. PRINCIPLE

The organic compounds in an aliquot portion of the extract are oxidized with hydrogen peroxide.

4. REAGENTS

4.1. Dilute hydrochloric acid (HCl) solution, about 0,5 mol/l

Mix 1 volume of hydrochloric acid (d20 = 1,18 g/ml) with 20 volumes of water.

4.2. Hydrogen peroxide solution (30 % H2O2, d20 = 1,11 g/ml), free from micro-nutrients

5. APPARATUS

Electric hotplate with variable temperature control.

6. PROCEDURE

Take 25 ml of the extract solution obtained by Method 9.1 or Method 9.2 and place in a 100 ml beaker. In the case of Method 9.2, add 5 ml of the dilute hydrochloric acid solution (4.1). Then add 5 ml of the hydrogen peroxide solution (4.2). Cover with a watch glass. Allow oxidation to occur at room temperature for about one hour, then bring gradually to boiling and boil for half an hour. If necessary, add a further 5 ml of the hydrogen peroxide to the solution once it has cooled. Then boil to remove the excess hydrogen peroxide. Allow to cool and transfer quantitatively to a 50 ml volumetric flask and make up to volume. Filter where necessary.

Account should be taken of this dilution when taking aliquot portions and calculating the percentage of micro-nutrient in the product.

Method 9.4 DETERMINATION OF MICRO-NUTRIENTS IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY (general procedure)

1. SCOPE

This document defines a general procedure for determining the levels of certain micro-nutrients in fertilizer extracts by atomic absorption spectrometry.

2. FIELD OF APPLICATION

This procedure is applicable to analyzing samples of fertilizers extracted by Methods 9.1 and 9.2 for which a declaration of total and/or water-soluble element is required by Annex I E to this Regulation.

Adaptations of this procedure for the various micro-nutrients are detailed in the methods defined specifically for each element.

Note

In most cases the presence of small quantities of organic matter will not affect determinations by atomic absorption spectrometry.

3. PRINCIPLE

After the extract has been treated where necessary to reduce or eliminate interfering chemical species, the extract is diluted so that its concentration is in the optimum range of the spectrometer at a wave-length suitable for the micro-nutrient to be determined.

4. REAGENTS

4.1. Dilute hydrochloric acid solution (HCl), about 6 mol/l

Mix one volume of hydrochloric acid (d20 = 1,18 g/ml) with one volume of water.

4.2. Dilute hydrochloric acid solution (HCl), about 0,5 mol/l

Mix one volume of hydrochloric acid (d20 = 1,18 g/ml) with 20 volumes of water.

4.3. Lanthanum salt solutions (10 g of La per litre)

This reagent is used for determinations of cobalt, iron, manganese and zinc. It can be prepared either:

a) with lanthanum oxide dissolved in hydrochloric acid (4.1). Place 11,73 g of lanthanum oxide (La2O3) in 150 ml of water in a one litre volumetric flask and add 120 ml of 6 mol/l hydrochloric acid (4.1). Allow to dissolve and then make up to 1 litre with water and mix thoroughly. This solution is approximately 0,5 mol/l in hydrochloric acid

b) or with solutions of lanthanum chloride, sulphate or nitrate. Dissolve 26,7 g of lanthanum chloride heptahydrate (LaCl3 7H2O) or 31,2 g of lanthanum nitrate hexahydrate [La(NO3)3 6H2O] or 26,2 g of lanthanum sulphate nonahydrate [La2(SO4)3 9H2O] in 150 ml of water, then add 85 ml of 6 mol/l hydrochloric acid (4.1). Allow to dissolve and then make up to 1 litre with water. Mix thoroughly. This solution is approximately 0,5 mol/l in hydrochloric acid.

4.4. Calibration solutions

For the preparation of these, see the individual determination Method for each micro-nutrient.

5. APPARATUS

Atomic absorption spectrometer fitted with sources emitting radiation characteristic of the micro-nutrients to be determined.

The analyst must follow the manufacturer's instructions and be familiar with the apparatus. The apparatus must allow background correction so that it can be used whenever necessary (Co and Zn). The gases to be used are air and acetylene.

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Preparation of extract solutions of the micro-nutrients to be determined.

See Methods 9.1 and/or 9.2 and, if appropriate, 9.3.

6.2. Treatment of the test solution

Dilute an aliquot portion of the extract obtained by Method 9.1, 9.2 or 9.3 with water and/or hydrochloric acid (4.1) or (4.2) so as to obtain, in the final solution for measurement, a concentration of the element to be determined that is appropriate to the calibration range used (7.2) and a hydrochloric acid concentration of at least 0,5 mol/l and not more than 2,5 mol/l. This operation may require one or more successive dilutions.

Take an aliquot portion of the final solution obtained by dilution of the extract, let (a) be its volume in ml, and pour into a 100 ml volumetric flask. When determining the cobalt, iron, manganese or zinc content, add 10 ml of the lanthanum salt solution (4.3). Make up to volume with the 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly. This is the final solution for measurement. Let D be the dilution factor.

7. PROCEDURE

7.1. Preparation of a blank solution

Prepare a blank solution by repeating the whole procedure from the extraction stage, omitting only the test sample of fertilizer.

7.2. Preparation of calibration solutions

From the working calibration solution prepared using the Method given for each individual micro-nutrient, prepare in 100 ml volumetric flasks a series of at least five calibration solutions of increasing concentration within the optimum measuring range of the spectrometer. If necessary, adjust the concentration of hydrochloric acid to bring it as close as possible to that of the diluted test solution (6.2). For determining cobalt, iron, manganese or zinc, add 10 ml of the same lanthanum salt solution (4.3) as used in 6.2. Make up to volume with the 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly.

7.3. Determination

Prepare the spectrometer (5) for the determination and adjust to the wavelength given in the Method for the individual micro-nutrient concerned.

Spray three times in succession the calibration solutions (7.2), the test solution (6.2) and the blank solution (7.1), noting each result and flushing the instrument with distilled water between individual sprayings.

Construct the calibration curve by plotting the average spectrometer reading for each calibration solution (7.2) along the ordinate and the corresponding concentration of the element, expressed in µg/ml, along the abscissa.

From this curve, determine the concentrations of the relevant micro-nutrient in the test solution xs (6.2) and in the blank solution xb (7.1), expressing these concentrations in µg per ml.

8. EXPRESSION OF RESULTS

The percentage of micro-nutrient (E) in the fertilizer is equal to:

E (%) = [(xs - xb) × V × D] / (M × 104)

If Method 9.3 has been used:

E (%) = [(xs - xb) × V × 2D] / (M × 104)

Where

E is the amount of the micro-nutrient determined, expressed as a percentage of the fertilizer;

xs is the concentration of the test solution (6.2), in µg/ml;

xb is the concentration of the blank solution (7.1), in µg/ml;

V is the volume of the extract obtained by Method 9.1 or 9.2, in ml;

D is the factor corresponding to the dilution carried out in 6.2;

M is the mass of the test sample taken in accordance with Method 9.1 or 9.2, in grams.

Calculation of dilution factor D:

If (a1), (a2), (a3), ., ., ., (ai) and (a) are the aliquot portions and (v1), (v2), (v3), ., ., ., (vi) and (100) are the volumes in ml corresponding to their respective dilutions, the dilution factor D will be equal to:

D = (v1/a1) × (v2/a2) × (v3/a3) ×. × . × . × (vi/ai) × (100/a)

Method 9.5 DETERMINATION OF BORON IN FERTILIZER EXTRACTS BY MEANS OF SPECTROMETRY WITH AZOMETHINE-H

1. SCOPE

This Method describes a procedure for determining boron in fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to analyzing samples of fertilizers extracted by Methods 9.1 and 9.2 for which a declaration of total and/or water-soluble boron is required by Annex I to this Regulation.

3. PRINCIPLE

In an azomethine-H solution, borate ions form a yellow complex the concentration of which is determined by molecular absorption spectrometry at 410 nm. Interfering ions are masked with EDTA.

4. REAGENTS

4.1. EDTA buffer solution

Place in a 500 ml volumetric flask containing 300 ml of water:

- 75 g of ammonium acetate (NH4OOCCH3);

- 10 g of disodium salt of ethylene diamine tetraacetic acid (Na2EDTA);

- 40 ml of acetic acid (CH3COOH, d20 = 1,05 g/ml).

Make up to volume with water and mix thoroughly. The pH of the solution, checked by means of a glass electrode, must be 4,8 + 0,1.

4.2. Azomethine-H solution

Place in a 200 ml volumetric flask

- 10 ml of the buffer solution (4.1);

- 400 mg of azomethine-H (C17H12NnaO8S2);

- 2 g of absorbic acid (C6H8O6).

Make up to volume and mix thoroughly. Do not prepare large quantities of this reagent as it is stable for only a few days.

4.3. Boron calibration solutions

4.3.1. Boron stock solution (100 µg/ml)

Dissolve 0,5719 g of boric acid (H2BO3) in water in a 1 000 ml volumetric flask. Make up to volume with water and mix thoroughly. Transfer to a plastic bottle for storage in a refrigerator.

4.3.2. Boron working solution (10 µg/ml)

Place 50 ml of stock solution (4.3.1) in a 500 ml volumetric flask. Make up to volume with water and mix thoroughly.

5. APPARATUS

Spectrometer fitted for molecular absorption with cells having a 10 mm optical path and set to a wavelength of 410 nm.

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Preparation of the boron solution

See Methods 9.1 and/or 9.2 and, if appropriate, 9.3.

6.2. Preparation of the test solution

Dilute an aliquot portion of extract (6.1) to obtain a boron concentration as specified in 7.2. Two successive dilutions may be necessary. Let D be the dilution factor.

6.3. Preparation of the correction solution

If the test solution (6.2) is coloured, prepare a corresponding correction solution by placing in a plastic flask 5 ml of test solution (6.2), 5 ml of EDTA buffer solution (4.1) and 5 ml of water and mix thoroughly.

7. PROCEDURE

7.1. Preparation of the blank solution

Prepare a blank solution by repeating the whole procedure from the extraction stage, omitting only the test sample of fertilizer.

7.2. Preparation of the calibration solutions

Transfer 0, 5, 10, 15, 20 and 25 ml of the working calibration solution (4.3.3) to a series of 100 ml volumetric flasks. Make up to 100 ml with water and mix thoroughly. These solutions contain between 0 and 2,5 µg/ml of boron.

7.3. Colour development

Transfer 5 ml of the calibration solutions (7.2), test solutions (6.2) and blank (7.1) to a series of plastic flasks. Add 5 ml of the EDTA buffer solution (4.1). Add 5 ml of the azomethine-H solution (4.2).

Mix thoroughly and allow the colour to develop in the dark for 2½ to three hours.

7.4. Determination

Measure the absorbance of the solutions obtained at 7.3 and if appropriate the correction solution (6.3) against water at a wavelength of 410 nm. Rinse the cells with water before each new reading.

8. EXPRESSION OF RESULTS

Plot a calibration curve of the concentration of the calibration solutions (7.2) along the abscissa and the absorbance given by the spectrometer (7.4) along the ordinate.

Read off the calibration curve the concentration of boron in the blank (7.1), the concentration of boron in the test solution (6.2) and, if the test solution is coloured, the corrected concentration of the test solution. To calculate the latter, subtract the absorbance of the correction solution (6.3) from the absorbance of the test solution (6.2) and determine the corrected concentration of the test solution. Note the concentration of the test solution (6.2), with or without correction, X(xs) and of the blank (xb).

The percentage of boron in the fertilizer is given by:

B % = [(xs - xb) × V × D] / (M × 104)

If Method 9.3 is used:

B % = [(xs - xb) × V × 2D] / (M × 104)

where

B is the quantity of boron expressed as a percentage of the fertilizer;

xs is the concentration (µg/ml) in the test solution (6.2), with or without correction;

xb is the concentration (µg/ml) in the blank (7.1);

V is the volume in ml of extract obtained in accordance with Method 9.1 or 9.2;

D is the factor corresponding to the dilution carried out in 6.2;

M is the mass in grams of the test sample taken in accordance with Method 9.1 or 9.2.

Calculation of the dilution factor D: if (a1) and (a2) are successive aliquot portions and (v1) and (v2) are the volumes corresponding to their respective dilutions, the dilution factor D is given by:

D = (v1/a1) × (v2/a2)

Method 9.6 DETERMINATION OF COBALT IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY

1. SCOPE

This Method describes a procedure for determining cobalt in fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to analyzing samples of fertilizers extracted by Methods 9.1 and 9.2 for which a declaration of total and/or water-soluble cobalt is required by Annex I E of this Regulation.

3. PRINCIPLE

After suitable treatment and dilution of the extracts, the cobalt content is determined by atomic absorption spectrometry.

4. REAGENTS

4.1. Hydrochloric acid solution, about 6 mol/l

See Method 9.4 (4.1).

4.2. Hydrochloric acid solution, about 0,5 mol/l

See Method 9.4 (4.2).

4.3. Lanthanum salt solutions (10 g of La per litre)

See Method 9.4 (4.3).

4.4. Cobalt calibration solutions

4.4.1. Cobalt stock solution (1 000 µg/ml)

In a 250 ml beaker, weigh to the nearest 0,1 mg, 1 g of cobalt, add 25 ml of 6 mol/l hydrochloric acid (4.1) and heat on a hotplate until the cobalt is completely dissolved. When cool, transfer quantitatively to a 1 000 ml volumetric flask. Make up to volume with water and mix thoroughly.

4.4.2. Cobalt working solution (100 µg/ml)

Place 10 ml of the stock solution (4.4.1) in a 100 ml volumetric flask. Make up to volume with 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly.

5. APPARATUS

Atomic absorption spectrometer: see Method 9.4 (5). The instrument must be equipped with a source of rays characteristic of cobalt (240,7 nm). The spectrometer must allow background correction to be made.

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Cobalt extract solution

See Methods 9.1 and/or 9.2 and, if appropriate, 9.3.

6.2. Preparation of the test solution

See Method 9.4 (6.2). The test solution must contain 10 % (v/v) of a lanthanum salt solution (4.3).

7. PROCEDURE

7.1. Preparation of blank solution

See Method 9.4 (7.1). The blank must contain 10 % (v/v) of the lanthanum salt solution used in 6.2.

7.2. Preparation of calibration solutions

See Method 9.4 (7.2).

For an optimum determination range of 0 to 5 µg/ml of cobalt, place 0, 0,5, 1, 2, 3, 4 and 5 ml respectively of working solution (4.4.2) in a series of 100 ml volumetric flasks. If necessary adjust the hydrochloric acid concentration as closely as possible to that of the test solution. Add to each flask 10 ml of the lanthanum salt solution used in 6.2. Make up to 100 ml with 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly. These solutions contain 0, 0,5, 1, 2, 3, 4 and 5 µg/ml respectively of cobalt.

7.3. Determination

See Method 9.4 (7.3). Prepare the spectrometer (5) for measurement at a wavelength of 240,7 nm.

8. EXPRESSION OF RESULTS

See Method 9.4 (8).

The percentage of cobalt in the fertilizer is given by:

Co % = [xs - xb) × V × D] / (M × 104)

If Method 9.3 is used:

Co % = [xs - xb) × V × 2D] / (M × 104)

where

Co is the quantity of cobalt expressed as a percentage of the fertilizer;

xs is the concentration in µg/ml of the test solution (6.2);

xb is the concentration in µg/ml of the blank solution (7.1);

V is the volume in ml of extract obtained in accordance with Method 9.1 or 9.2;

D is the factor corresponding to the dilution carried out in 6.2;

M is the mass in grams of the test sample taken in accordance with Method 9.1 or 9.2.

Calculation of the dilution factor D: if (a1), (a2), (a3), ., ., ., (ai) and (a) are aliquot portions and (v1), (v2), (v3), ., ., ., (vi) and (100) are the volumes in ml corresponding to their respective dilutions, the dilution factor D is given by:

D = (v1/a1) × (v2/a2) × (v3/a3) × . × . ×. × . × (vi/ai) × (100/a)

Method 9.7 DETERMINATION OF COPPER IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY

1. SCOPE

This Method describes a procedure for determining copper in fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to analyzing samples of fertilizers extracted by Methods 9.1 and 9.2 for which a declaration of total and/or water-soluble copper is required by Annex I E to this Regulation.

3. PRINCIPLE

After suitable treatment and dilution of the extracts, the copper content is determined by atomic absorption spectrometry.

4. REAGENTS

4.1. Hydrochloric acid solution, about 6 mol/l

See Method 9.4 (4.1).

4.2. Hydrochloric acid solution, about 0,5 mol/l

See Method 9.4 (4.2).

4.3. Hydrogen peroxide solution (30 % H2O2, d20 = 1,11 g/ml), free from micro-nutrients

4.4. Copper calibration solutions

4.4.1. Copper stock solution (1 000 µg/ml)

In a 250 ml beaker, weigh to the nearest 0,1 mg, 1 g of copper, add 25 ml of 6 mol/l hydrochloric acid (4.1), add 5 ml hydrogen peroxide solution (4.3) and heat on a hotplate until the copper is completely dissolved. Transfer quantitatively to a 1 000 ml volumetric flask. Make up to volume with water and mix thoroughly.

4.4.2. Copper working solution (100 µg/ml)

Place 20 ml of the stock solution (4.4.1) in a 200 ml volumetric flask. Make up to volume with 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly.

5. APPARATUS

Spectrometer equipped for atomic absorption: see Method 9.4 (5). The instrument must be fitted with a source of rays characteristics of copper (324,8 nm).

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Copper extract solution

See Methods 9.1 and/or 9.2 and, if appropriate, 9.3.

6.2. Preparation of the test solution

See Method 9.4 (6.2).

7. PROCEDURE

7.1. Preparation of blank solution

See Method 9.4 (7.1).

7.2. Preparation of calibration solutions

See Method 9.4 (7.2).

For an optimum determination range of 0 to 5 µg/ml of copper, place 0, 0,5, 1, 2, 3, 4 and 5 ml respectively of working solution (4.4.2) in a series of 100 ml volumetric flasks. If necessary adjust the hydrochloric acid concentration as closely as possible to that of the test solution (6.2). Make up to 100 ml with 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly. These solutions contain 0, 0,5, 1, 2, 3, 4 and 5 µg/ml respectively of copper.

7.3. Determination

See Method 9.4 (7.3). Prepare the spectrometer (5) for measurement at a wavelength of 324,8 nm.

8. EXPRESSION OF RESULTS

See Method 9.4 (8).

The percentage of copper in the fertilizer is given by:

Cu % = [xs - xb) × V × D] / (M × 104)

If Method 9.3 is used:

Cu % = [xs - xb) × V × 2D] / (M × 104)

where

Cu is the quantity of copper expressed as a percentage of the fertilizer;

xs is the concentration in µg/ml of the test solution (6.2);

xb is the concentration in µg/ml of the blank solution (7.1);

V is the volume in ml of extract obtained in accordance with Method 9.1 or 9.2;

D is the factor corresponding to the dilution carried out in 6.2;

M is the mass in grams of the test sample taken in accordance with Method 9.1 or 9.2.

Calculation of the dilution factor D: if (a1), (a2), (a3), ., ., ., (ai) and (a) are aliquot portions and (v1), (v2), (v3), ., ., ., (vi) and (100) are the volumes in ml corresponding to their respective dilutions, the dilution factor D is given by:

D = (v1/a1) × (v2/a2) × (v3/a3) × . × . ×. × . × (vi/ai) × (100/a)

Method 9.8 DETERMINATION OF IRON IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY

1. SCOPE

This Method describes a procedure for determining iron in fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to analyzing samples of fertilizers extracted by Methods 9.1 and 9.2 for which a declaration of total and/or water-soluble iron is required by Annex 1E of this Regulation.

3. PRINCIPLE

After suitable treatment and dilution of the extracts, the iron content is determined by atomic absorption spectrometry.

4. REAGENTS

4.1. Hydrochloric acid solution, about 6 mol/l

See Method 9.4 (4.1).

4.2. Hydrochloric acid solution, about 0,5 mol/l

See Method 9.4 (4.2).

4.3. Hydrogen peroxide solution (30 % H2O2, d20 = 1,11 g/ml), free from micro-nutrients

4.4. Lanthanum salt solutions (10 g of La per litre)

See Method 9.4 (4.3).

4.5. Iron calibration solutions

4.5.1. Iron stock solution (1 000 µg/ml)

In a 500 ml beaker, weigh to the nearest 0,1 mg, 1 g of iron wire, add 200 ml of 6 mol/l hydrochloric acid (4.1) and 15 ml of hydrogen peroxide solution (4.3). Heat on a hotplate until the iron is completely dissolved. When cool, transfer quantitatively to a 1 000 ml volumetric flask. Make up to volume with water and mix thoroughly.

4.5.2. Iron working solution (100 µg/ml)

Place 20 ml of the stock solution (4.5.1) in a 200 ml volumetric flask. Make up to volume with 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly.

5. APPARATUS

Atomic absorption spectrometer: see Method 9.4 (5). The instrument must be fitted with a source of rays characteristic of iron (248,3 nm).

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Iron extract solution

See Methods 9.1 and/or 9.2 and, if appropriate, 9.3.

6.2. Preparation of the test solution

See Method 9.4 (6.2). The test solution must contain 10 % (v/v) of a lanthanum salt solution.

7. PROCEDURE

7.1. Preparation of blank solution

See Method 9.4 (7.1). The test solution must contain 10 % (v/v) of the lanthanum salt solution used in 6.2.

7.2. Preparation of calibration solutions

See Method 9.4 (7.2).

For an optimum determination range of 0 to 10 µg/ml of iron, place 0, 2, 4, 6, 8 and 10 ml respectively of working solution (4.5.2) in a series of 100 ml volumetric flasks. If necessary adjust the hydrochloric acid concentration as closely as possible to that of the test solution. Add 10 ml of the lanthanum salt solution used in 6.2. Make up to volume with 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly. These solutions contain 0, 2, 4, 6, 8 and 10 µg/ml respectively of iron.

7.3. Determination

See Method 9.4 (7.3). Prepare the spectrometer (5) for measurement at a wavelength of 248,3 nm.

8. EXPRESSION OF RESULTS

See Method 9.4 (8).

The percentage of iron in the fertilizer is given by:

Fe % = [xs - xb) × V × D] / (M × 104)

If Method 9.3 is used:

Fe % = [xs - xb) × V × 2D] / (M × 104)

where

Fe is the quantity of iron expressed as a percentage of the fertilizer;

xs is the concentration in µg/ml of the test solution (6.2);

xb is the concentration in µg/ml of the blank solution (7.1);

V is the volume in ml of extract obtained in accordance with Method 9.1 or 9.2;

D is the factor corresponding to the dilution carried out in 6.2;

M is the mass in grams of the test sample taken in accordance with Method 9.1 or 9.2.

Calculation of the dilution factor D: if (a1), (a2), (a3), ., ., ., (ai) and (a) are aliquot portions and (v1), (v2), (v3), ., ., ., (vi) and (100) are the volumes in ml corresponding to their respective dilutions, the dilution factor D is given by:

D = (v1/a1) × (v2/a2) × (v3/a3) × . × . ×. × . × (vi/ai) × (100/a)

Method 9.9 DETERMINATION OF MANGANESE IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY

1. SCOPE

This Method describes a procedure for determining manganese in fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to analyzing samples of fertilizers extracted by Methods 9.1 and 9.2 for which a declaration of total and/or water-soluble manganese is required by Annex I E of this Regulation.

3. PRINCIPLE

After suitable treatment and dilution of the extracts, the manganese level is determined by atomic absorption spectrometry.

4. REAGENTS

4.1. Hydrochloric acid solution, about 6 mol/l

See Method 9.4 (4.1).

4.2. Hydrochloric acid solution, about 0,5 mol/l

See Method 9.4 (4.2).

4.3. Lanthanum salt solutions (10 g of La per litre)

See Method 9.4 (4.3).

4.4. Manganese calibration solutions

4.4.1. Manganese stock solution (1 000 µg/ml)

In a 250 ml beaker, weigh to the nearest 0,1 mg, 1 g of manganese, add 25 ml of 6 mol/l hydrochloric acid (4.1). Heat on a hotplate until the manganese is completely dissolved. When cool, transfer quantitatively to a 1 000 ml volumetric flask. Make up to volume with water and mix thoroughly.

4.4.2. Manganese working solution (100 µg/ml)

Dilute 20 ml of the stock solution (4.4.1) in the 0,5 mol/l hydrochloric acid solution (4.2) in a 200 ml volumetric flask. Make up to volume with 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly.

5. APPARATUS

Atomic absorption spectrometer: see Method 9.4 (5). The instrument must be fitted with a source of lines characteristic of manganese (279,6 nm).

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Manganese extract solution

See Methods 9.1 and/or 9.2 and, if appropriate, 9.3.

6.2. Preparation of the test solution

See Method 9.4 (6.2). The test solution must contain 10 % by volume of lanthanum salt solution (4.3).

7. PROCEDURE

7.1. Preparation of blank solution

See Method 9.4 (7.1). The test solution must contain 10 % by volume of the lanthanum salt solution used in 6.2.

7.2. Preparation of calibration solutions

See Method 9.4 (7.2).

For an optimum determination range of 0 to 5 µg/ml of manganese, place 0, 0,5, 1, 2, 3, 4 and 5 ml respectively of working solution (4.4.2) in a series of 100 ml volumetric flasks. Where necessary adjust the hydrochloric acid concentration to bring it as close as possible to that of the test solution. To each flask, add 10 ml of the lanthanum salt solution used in 6.2. Make up to 100 ml with 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly. These solutions contain 0, 0,5, 1, 2, 3, 4 and 5 µg/ml respectively of manganese.

7.3. Determination

See Method 9.4 (7.3). Prepare the spectrometer (5) for measurement at a wavelength of 279,6 nm.

8. EXPRESSION OF RESULTS

See Method 9.4 (8).

The percentage of manganese in the fertilizer is as follows:

Mn % = [xs - xb) × V × D] / (M × 104)

If Method 9.3 is used:

Mn % = [xs - xb) × V × 2D] / (M × 104)

where

Mn is the quantity of manganese expressed as a percentage of the fertilizer;

xs is the concentration in µg/ml of the test solution (6.2);

xb is the concentration in µg/ml of the blank solution (7.1);

V is the volume in ml of extract obtained in accordance with Method 9.1 or 9.2;

D is the factor corresponding to the dilution carried out in 6.2;

M is the mass in grams of the test sample taken in accordance with Method 9.1 or 9.2.

Calculation of the dilution factor D: if (a1), (a2), (a3), ., ., ., (ai) and (a) are aliquot portions and (v1), (v2), (v3), ., ., ., (vi) and (100) are the volumes in ml corresponding to their respective dilutions, the dilution factor D will be equal to:

D = (v1/a1) × (v2/a2) × (v3/a3) × . × . ×. × . × (vi/ai) × (100/a)

Method 9.10 DETERMINATION OF MOLYBDENUM IN FERTILIZER EXTRACTS BY SPECTROMETRY OF A COMPLEX WITH AMMONIUM THIOCYANATE

1. SCOPE

This Method describes a procedure for determining molybdenum in fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to analyzing samples of fertilizers extracted by Methods 9.1 and 9.2 for which a declaration of total and/or water-soluble molybdenum is required by Annex I E to this Regulation.

3. PRINCIPLE

Molybdenum (V) forms a complex [MoO(SCN)5]-in an acid medium with SCN- ions.

The complex is extracted with n-butyl acetate. Interfering ions such as those of iron remain in the aqueous phase. The yellow-orange colour is determined by molecular absorption sectrometry at 470 nm.

4. REAGENTS

4.1. Dilute hydrochloric acid solution (HCl), about 6 mol/l

See Method 9.4 (4.1).

4.2. Copper solution (70 mg/l) in 1,5 mol/l hydrochloric acid

Dissolve 275 mg of copper sulphate (CuSO4 5H2O) weighed to within 0,1 mg in 250 ml of the 6 mol/l hydrochloric acid solution (4.1) in a 1 000 ml volumetric flask. Make up to volume with water and mix thoroughly.

4.3. Ascorbic acid solution (50 g/l)

Dissolve 50 g of ascorbic acid (C6H8O6) in water in a 1 000 ml volumetric flask. Make up to volume with water, mix thoroughly and keep in a refrigerator.

4.4. n-butyl acetate.

4.5. Ammonium thiocyanate solution, 0,2 mol/l

Dissolve 15,224 g of NH4SCN in water in a 1 000 ml volumetric flask. Make up to volume with water; mix thoroughly and store in a dark-coloured bottle.

4.6. Stannous chloride solution (50 g/l) in 2 mol/l hydrochloric acid

This solution must be perfectly clear and prepared immediately before use. Very pure stannous chloride must be used otherwise the solution will not be clear.

To prepare 100 ml of solution, dissolve 5 g of (SnCl22H2O) in 35 ml of 6 mol/l HCl solution (4.1). Add 10 ml of the copper solution (4.2). Make up to volume with water and mix thoroughly.

4.7. Molybdenum calibration solutions

4.7.1. Molybdenum stock solution (500 µg/ml)

Dissolve 0,920 g of ammonium molybdate [(NH4)6Mo7O24 4H2O] weighed to within 0,1 mg in the 6 mol/l hydrochloric acid (4.1) in a 1 000 ml volumetric flask. Make up to volume with that solution and mix thoroughly.

4.7.2. Molybdenum intermediate solution (25 µg/ml)

Place 25 ml of the stock solution (4.7.1) in a 500 ml volumetric flask. Make up to volume with 6 mol/l hydrochloric acid (4.1) and mix thoroughly.

4.7.3. Molybdenum working solution (2,5 µg/ml)

Place 10 ml of the intermediate solution (4.7.2) in a 100 ml volumetric flask. Make up to volume with 6 mol/l hydrochloric acid (4.1) and mix thoroughly.

5. APPARATUS

5.1. Spectrometer fitted for molecular absorption with cuvettes having a 20 mm optical path and set to a wavelength of 470 nm

5.2. 200 or 250 ml separating funnels

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Molybdenum extract solution

See Methods 9.1 and/or 9.2 and, if appropriate, 9.3.

6.2. Preparation of the test solution

Dilute an aliquot portion of the extract (6.1) with 6 mol/l hydrochloric acid solution (4.1) so as to obtain an appropriate molybdenum concentration. Let D be the dilution factor.

Take an aliquot portion (a) from the extract solution containing 1 to 12 µg molybdenum and place it in the separating funnel (5.2). Make up to 50 ml with the 6 mol/l hydrochloric acid solution (4.1).

7. PROCEDURE

7.1. Preparation of the blank solution

Prepare a blank solution by repeating the whole procedure from the extraction stage, omitting only the test sample of fertilizer.

7.2. Preparation of the series of calibration solutions

Prepare a series of at least six calibration solutions of increasing concentration corresponding to the optimum response range of the spectrometer.

For the interval 0-12,5 µg molybdenum, place 0, 1, 2, 3, 4 and 5 ml respectively of working solution (4.7.3) in the separating funnels (5.2). Make up to 50 ml with 6 mol/l hydrochloric acid (4.1). The funnels contain respectively 0, 2,5, 5, 7,5, 10 and 12,5 µg molybdenum.

7.3. Development and separation of the complex

To each separating funnel (6.2, 7.1 and 7.2), add in the following order:

- 10 ml of the copper solution (4.2)

- 20 ml of the ascorbic acid solution (4.3);

mix thoroughly and wait for two or three minutes. Then add:

- 10 ml of n-butyl acetate (4.4), using a precision pipette

- 20 ml of the thiocyanate solution (4.5).

Shake for one minute to extract the complex in the organic phase; allow to precipitate; after the separation of the two phases, draw off the entire aqueous phase and discard it; then wash the organic phase with:

- 10 ml of the stannous chloride solution (4.6).

Shake for one minute. Allow to precipitate and draw off the entire aqueous phase. Collect the organic phase in a test tube; this will make it possible to collect the drops of water in suspension.

7.4. Determination

Measure the absorbencies of the solutions obtained at 7.3 at a wavelength of 470 nm using the 0 µg/ml molybdenum calibration solution (7.2) as a reference.

8. EXPRESSION OF RESULTS

Construct the calibration curve by plotting the corresponding masses of molybdenum in the calibration solutions (7.2) expressed in µg along the abscissa and the corresponding values of the absorbencies (7.4) given by the spectrometer reading along the ordinate.

From this curve determine the mass of molybdenum in the test solution (6.2) and the blank solution (7.1). These masses are designated (xs) and (xb) respectively.

The percentage of molybdenum in the fertilizer is:

Mo % = [xs - xb) × V/a × D] / (M × 104)

If Method 9.3 is used:

Mn % = [xs - xb) × V/a × 2D] / (M × 104)

where

Mo is the quantity of molybdenum expressed as a percentage of the fertilizer;

a is the volume in ml of the aliquot taken from the last dilute solution (6.2);

xs is the Mo mass in µg in the test solution (6.2);

xb is the Mo mass in µg in the blank solution (7.1) the volume of which corresponds to the volume (a) of the aliquot of the test solution (6.2);

V is the volume in ml of extract solution obtained in accordance with Method 9.1 or 9.2;

D is the factor corresponding to the dilution performed in 6.2;

M is the mass in grams of the test sample taken in accordance with Method 9.1 or 9.2.

Calculation of the dilution factor D: where (a1), (a2) are successive aliquot portions and (v1), (v2) are the volumes corresponding to their respective dilutions, the dilution factor D will be:

D = (v1/a1) × (v2/a2)

Method 9.11 DETERMINATION OF ZINC IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY

1. SCOPE

This Method describes a procedure for determining zinc in fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to analyzing samples of fertilizers extracted by Methods 9.1 and 9.2 for which a declaration of total and/or water-soluble zinc is required by Annex I E to this Regulation.

3. PRINCIPLE

After suitable treatment and dilution of the extracts, the zinc level is determined by atomic absorption spectrometry.

4. REAGENTS

4.1. Hydrochloric acid solution, about 6 mol/l

See Method 9.4 (4.1).

4.2. Hydrochloric acid solution, about 0,5 mol/l

See Method 9.4 (4.2).

4.3. Lanthanum salt solutions (10 g of La per litre)

See Method 9.4 (4.3).

4.4. Zinc calibration solutions

4.4.1 Zinc stock solution (1 000 µg/ml)

In a 1 000 ml volumetric flask, dissolve 1 g of zinc powder or flakes weighed to within 0,1 mg in 25 ml of 6 mol/l hydrochloric acid (4.1). When completely dissolved, make up to volume with water and mix thoroughly.

4.4.2. Zinc working solution (100 µg/ml)

In a 200 ml volumetric flask, dilute 20 ml of the stock solution (4.4.1) in 0,5 mol/l hydrochloric acid solution (4.2). Make up to volume with the 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly.

5. APPARATUS

Atomic absorption spectrometer: see Method 9.4 (5). The instrument must be fitted with a source of lines characteristic of zinc (213,8 nm), the spectrometer must allow background correction to be made.

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Zinc extract solution

See Methods 9.1 and/or 9.2 and, if appropriate, 9.3.

6.2. Preparation of the test solution

See Method 9.4 (6.2). The test solution must contain 10 % by volume of lanthanum salt solution (4.3).

7. PROCEDURE

7.1. Preparation of blank solution

See Method 9.4 (7.1). The test solution must contain 10 % by volume of the lanthanum salt solution used in 6.2.

7.2. Preparation of calibration solutions

See Method 9.4 (7.2).

For an optimum interval of 0 to 5 µg/ml of zinc, place 0, 0,5, 1, 2, 3, 4 and 5 ml respectively of working solution (4.4.2) in a series of 100 ml volumetric flasks. Where necessary adjust the hydrochloric acid concentration to bring it as close as possible to that of the test solution. To each flask, add 10 ml of the lanthanum salt solution used in 6.2. Make up to 100 ml with 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly. These solutions contain 0, 0,5, 1, 2, 3, 4 and 5 µg/ml respectively of zinc.

7.3. Determination

See Method 9.4 (7.3). Prepare the spectrometer (5) for measurement at a wavelength of 213,8 nm.

8. EXPRESSION OF RESULTS

See Method 9.4 (8).

The percentage of zinc in the fertilizer is as follows:

Zn % = [xs - xb) × V × D] / (M × 104)

If Method 9.3 is used:

Zn % = [xs - xb) × V × 2D] / (M × 104)

where

Zn is the quantity of zinc expressed as a percentage of the fertilizer;

xs is the concentration in µg/ml of the test solution (6.2);

xb is the concentration in µg/ml of the blank solution (7.1);

V is the volume in ml of extract obtained in accordance with Method 9.1 or 9.2;

D is the factor corresponding to the dilution carried out in 6.2;

M is the mass in grams of the test sample taken in accordance with Method 9.1 or 9.2.

Calculation of the dilution factor D: if (a1), (a2), (a3), ., ., ., (ai) and (a) are aliquot portions and (v1), (v2), (v3), ., ., ., (vi) and (100) are the volumes in ml corresponding to their respective dilutions, the dilution factor D will be equal to:

D = (v1/a1) × (v2/a2) × (v3/a3) × . × . ×. × . × (vi/ai) × (100/a)

Methods 10 MICRO-NUTRIENTS AT A CONCENTRATION GREATER THAN 10 %

Method 10.1 EXTRACTION OF TOTAL MICRO-NUTRIENTS

1. SCOPE

This Method defines the procedure for extracting the following micro-nutrients: total boron, total cobalt, total copper, total iron, total manganese, total molybdenum and total zinc. The aim is to carry out the minimum number of extractions, making use wherever possible of the same extract to determine the total level of each of the micro-nutrients listed above.

2. FIELD OF APPLICATION

This procedure concerns Community fertilizers covered by Annex I E to this Regulation containing one or more of the following micro-nutrients: boron, cobalt, copper, iron, manganese, molybdenum and zinc. It is applicable to each micro-nutrient the declared content of which is more than 10 %.

3. PRINCIPLE

Dissolution in boiling dilute hydrochloric acid.

Note

The extraction is empirical and may not be quantitative depending on the product or the other constituents of the fertilizer. In particular, in the case of certain manganese oxides, the quantity extracted may be substantially smaller than the total quantity of manganese which the product contains. It is the responsibility of the fertilizer manufacturers to ensure that the declared content actually corresponds to the quantity extracted under the conditions pertaining to the method.

4. REAGENTS

4.1. Dilute hydrochloric acid (HCl) solution, about 6 mol/l

Mix 1 volume of hydrochloric acid (d20 = 1,18 g/ml) with 1 volume of water.

4.2. Concentrated ammonia solution (NH4OH, d20 = 0,9 g/ml)

5. APPARATUS

5.1. Electric hotplate with variable temperature control

5.2. pH meter

Note

Where the boron content of an extract is to be determined, do not use borosilicate glassware. As the Method involves boiling, teflon or silica is preferable. Rinse the glassware thoroughly if it has been washed in detergents containing borates.

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Test sample

Take a quantity of fertilizer weighing 1 or 2 g depending on the declared content of element in the product. The following table shall be used to obtain a final solution which, after appropriate dilution, will be within the measuring range for each method. Samples should be weighed to within 1 mg.

>TABLE POSITION>

Place the sample in a 250 ml beaker.

7.2. Preparation of the solution

If necessary moisten the sample with a little water, add 10 ml of dilute hydrochloric acid (4.1) per gram of fertilizer carefully, in small amounts, then add about 50 ml of water. Cover the beaker with a watch glass and mix. Bring to the boil on the hotplate and boil for 30 minutes. Allow to cool, stirring occasionally. Transfer quantitatively to a 500 ml volumetric flask. Make up to volume with water and mix thoroughly. Filter through a dry filter into a dry container. Discard the first portion. The extract must be perfectly clear.

It is recommended that the determination be carried out without delay on aliquot portions of the clear filtrate, if not the containers should be stoppered.

Note

Extracts in which the boron content has to be determined: Adjust the pH to between 4 and 6 with concentrated ammonia (4.2).

8. DETERMINATION

The determination of each micro-nutrient is to be carried out on the aliquot portions indicated in the Method for each individual micro-nutrient.

Methods 10.5, 10.6, 10.7, 10.9 and 10.10 cannot be used to determine elements present in a chelated or complexed form. In such cases Method 10.3 must be used prior to the determination.

In the case of determination by AAS (Methods 10.8 and 10.11) such treatment may not be necessary.

Method 10.2 EXTRACTION OF WATER-SOLUBLE MICRO-NUTRIENTS

1. SCOPE

This Method defines the procedure for extracting water-soluble forms of the following micro-nutrients: boron, cobalt, copper, iron, manganese, molybdenum and zinc. The aim is to carry out the minimum number of extractions, making use wherever possible of the same extract to determine the level of each of the micro-nutrients listed above.

2. FIELD OF APPLICATION

This procedure concerns Community fertilizers covered by Annex IE to this Regulation containing one or more of the following micro-nutrients: boron, cobalt, copper, iron, manganese, molybdenum and zinc. It is applicable to each micro-nutrient the declared content of which is more than 10 %.

3. PRINCIPLE

The micro-nutrients are extracted by shaking the fertilizer in water at 20 °C ± 2 °C.

Note

The extraction is empirical and may or may not be quantitative.

4. REAGENTS

4.1. Dilute hydrochloric acid (HCl) solution, about 6 mol/l

Mix 1 volume of hydrochloric acid (d20 = 1,18 g/ml) with 1 volume of water.

5. APPARATUS

5.1. Rotary shaker set at about 35 to 40 rpm

Note

Where the boron content of the extract is to be determined, do not use borosilicate glassware. Teflon or silica is preferable for this extraction. Rinse the glassware thoroughly if it has been washed in detergents containing borates.

6. PREPARATION OF THE SAMPLE

See Method 1.

7. PROCEDURE

7.1. Test sample

Take a quantity of fertilizer weighing 1 or 2 g depending on the declared content of the product. The following table shall be used to obtain a final solution which, after appropriate dilution, will be within the measuring range for each method. The samples should be weighed to within 1 mg.

>TABLE POSITION>

Place the sample in a 500 ml flask.

7.2. Preparation of the solution

Add about 400 ml of water.

Stopper the flask well. Shake vigorously by hand to disperse the sample, then place the flask on the shaker and shake for 30 minutes.

Make up to volume with water and mix thoroughly.

7.3. Preparation of the test solution

Filter immediately into a clean, dry flask. Stopper the flask. Carry out the determination immediately after filtering.

Note

If the filtrate gradually becomes cloudy, make another extraction following 7.1 and 7.2 in a flask of volume Ve. Filter into a calibrated flask of volume W which has previously been dried and has received 5 ml of dilute hydrochloric acid (4.1). Stop the filtration at the exact moment when the calibration mark is reached. Mix thoroughly.

Under these conditions the value of V in the expression of results is:

V = Ve × W / (W - 5)

The dilutions in the expression of results depend on this value of V.

8. DETERMINATION

The determination of each micro-nutrient is carried out on the aliquot portions indicated in the Method for each individual micro-nutrient.

Methods 10.5, 10.6, 10.7, 10.9 and 10.10 cannot be used to determine elements present in a chelated or complexed form. In such cases Method 10.3 must be used prior to the determination.

In the case of determination by AAS (Methods 10.8 and 10.11) such treatment may not be necessary.

Method 10.3 REMOVAL OF ORGANIC COMPOUNDS FROM FERTILIZER EXTRACTS

1. SCOPE

This Method defines a procedure for removing organic compounds from fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to analyzing samples of fertilizers extracted by Methods 10.1 and 10.2 for which a declaration of total and/or water-soluble element is required by Annex I E to this Regulation.

Note

The presence of small quantities of organic matter usually does not affect determination by means of atomic absorption spectrometry.

3. PRINCIPLE

The organic compounds in an aliquot portion of the extract are oxidized with hydrogen peroxide.

4. REAGENTS

4.1. Dilute hydrochloric acid (HCl) solution, about 0,5 mol/l

Mix 1 volume of hydrochloric acid (d20 = 1,18 g/ml) with 20 volumes of water.

4.2. Hydrogen peroxide solution (30 % H2O2, d20 = 1,11 g/ml), free from micro-nutrients

5. APPARATUS

Electric hotplate with variable temperature control.

6. PROCEDURE

Take 25 ml of the extract solution obtained by Method 10.1 or Method 10.2 and place in a 100 ml beaker. In the case of Method 10.2, add 5 ml of the dilute hydrochloric acid solution (4.1). Then add 5 ml of the hydrogen peroxide solution (4.2). Cover with a watch glass. Allow oxidation to occur at room temperature for about one hour, then bring gradually to boiling and boil for half an hour. If necessary, add a further 5 ml of the hydrogen peroxide to the solution once it has cooled. Then boil to remove the excess hydrogen peroxide. Allow to cool and transfer quantitatively to a 50 ml volumetric flask and make up to volume. Filter where necessary.

Account should be taken of this dilution when taking aliquot portions and calculating the percentage of micro-nutrient in the product.

Method 10.4 DETERMINATION OF MICRO-NUTRIENTS IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY (general procedure)

1. SCOPE

This document defines a general procedure for determining the levels of iron and zinc in fertilizer extracts by atomic absorption spectrometry.

2. FIELD OF APPLICATION

This procedure is applicable to analyzing samples of fertilizers extracted by Methods 10.1 and 10.2 for which a declaration of total and/or water-soluble iron or zinc is required by Annex IE to this Regulation.

Adaptations of this procedure for the various micro-nutrients are detailed in the methods defined specifically for each element.

Note

In most cases the presence of small quantities of organic matter will not affect determinations by atomic absorption spectrometry.

3. PRINCIPLE

After the extract has been treated where necessary to reduce or eliminate interfering chemical species, the extract is diluted so that its concentration is in the optimum range of the spectrometer at a wave-length suitable for the micro-nutrient to be determined.

4. REAGENTS

4.1. Dilute hydrochloric acid solution (HCl), about 6 mol/l

Mix one volume of hydrochloric acid (d20 = 1,18 g/ml) with one volume of water.

4.2. Dilute hydrochloric acid solution (HCl), about 0,5 mol/l

Mix one volume of hydrochloric acid (d20 = 1,18 g/ml) with 20 volumes of water.

4.3. Lanthanum salt solutions (10 g of La per litre)

This reagent is used for determinations of iron and zinc. It can be prepared either:

a) with lanthanum oxide dissolved in hydrochloric acid (4.1). Place 11,73 g of lanthanum oxide (La2O3) in 150 ml of water in a one litre volumetric flask and add 120 ml of 6 mol/l hydrochloric acid (4.1). Allow to dissolve and then make up to 1 litre with water and mix thoroughly. This solution is approximately 0,5 mol/l in hydrochloric acid; or

b) with solutions of lanthanum chloride, sulphate or nitrate. Dissolve 26,7 g of lanthanum chloride heptahydrate (LaCl3 7H2O) or 31,2 g of lanthanum nitrate hexahydrate [La(NO3)3 6H2O] or 26,2 g of lanthanum sulphate nonahydrate [La2(SO4)3 9H2O] in 150 ml of water, then add 85 ml of 6 mol/l hydrochloric acid (4.1). Allow to dissolve and then make up to 1 litre with water. Mix thoroughly. This solution is approximately 0,5 mol/l in hydrochloric acid.

4.4. Calibration solutions

For the preparation of these, see the individual determination Method for each micro-nutrient.

5. APPARATUS

Atomic absorption spectrometer fitted with sources emitting radiation characteristic of the micro-nutrients to be determined.

The analyst must follow the manufacturer's instructions and be familiar with the apparatus. The apparatus must allow background correction so that it can be used whenever necessary (e.g. Zn). The gases to be used are air and acetylene.

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Preparation of extract solutions containing the elements to be determined

See Methods 10.1 and/or 10.2 and, if appropriate, 10.3.

6.2. Treatment of the test solution

Dilute an aliquot portion of the extract obtained by Method 10.1, 10.2 or 10.3 with water and/or hydrochloric acid (4.1) or (4.2) so as to obtain, in the final solution for measurement, a concentration of the element to be determined that is appropriate to the calibration range used (7.2) and a hydrochloric acid concentration of at least 0,5 mol/l and not more than 2,5 mol/l. This operation may require one or more successive dilutions.

The final solution has to be obtained by placing an aliquot portion of the diluted extract in a 100 ml volumetric flask. Let the volume of this aliquot portion be (a) ml. Add 10 ml of the lanthanum salt solution (4.3). Make up to volume with the 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly. Let D be the dilution factor.

7. PROCEDURE

7.1. Preparation of a blank solution

Prepare a blank solution by repeating the whole procedure from the extraction stage, omitting only the test sample of fertilizer.

7.2. Preparation of calibration solutions

From the working calibration solution prepared using the Method given for each individual micro-nutrient, prepare in 100 ml volumetric flasks a series of at least five calibration solutions of increasing concentration within the optimum measuring range of the spectrometer. If necessary, adjust the concentration of hydrochloric acid to bring it as close as possible to that of the diluted test solution (6.2). When determining iron or zinc, add 10 ml of the same lanthanum salt solution (4.3) as used in 6.2. Make up to volume with the 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly.

7.3. Determination

Prepare the spectrometer (5) for the determination and adjust to the wavelength given in the Method for the individual micro-nutrient concerned.

Spray three times in succession the calibration solutions (7.2), the test solution (6.2) and the blank solution (7.1), noting each result and flushing the instrument with distilled water between individual sprayings.

Construct the calibration curve by plotting the average spectrometer reading for each calibration solution (7.2) along the ordinate and the corresponding concentration of the element, expressed in µg/ml, along the abscissa.

From this curve, determine the concentrations of the relevant micro-nutrient in the test solution xs (6.2) and in the blank solution xb (7.1), expressing these concentrations in µg per ml.

8. EXPRESSION OF RESULTS

The percentage of micro-nutrient (E) in the fertilizer is given by:

E (%) = [(xs - xb) × V × D] / (M × 104)

If Method 10.3 has been used:

E (%) = [(xs - xb) × V × 2D] / (M × 104)

Where

E is the amount of the micro-nutrient determined, expressed as a percentage of the fertilizer;

xs is the concentration of the test solution (6.2), in µg/ml;

xb is the concentration of the blank solution (7.1), in µg/ml;

V is the volume of the extract obtained by Method 10.1 or 10.2, in ml;

D is the factor corresponding to the dilution carried out in 6.2;

M is the mass of the test sample taken in accordance with Method 10.1 or 10.2, in grams.

Calculation of dilution factor D:

If (a1), (a2), (a3), ., ., ., (ai) and (a) are the aliquot portions and (v1), (v2), (v3), ., ., ., (vi) and (100) are the volumes in ml corresponding to their respective dilutions, the dilution factor D will be equal to:

D = (v1/a1) × (v2/a2) × (v3/a3) ×. × . × . × (vi/ai) × (100/a)

Method 10.5 DETERMINATION OF BORON IN FERTILIZER EXTRACTS BY MEANS OF ACIDIMETRIC TITRATION

1. SCOPE

This Method defines a procedure for determining the boron content of fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to extracts from samples of fertilizers obtained by Methods 10.1 or Method 10.2 and for which a declaration of total and/or water-soluble boron is required by Annex I E to this Regulation.

3. PRINCIPLE

A mannitoboric complex if formed by the following reaction of the borate in with mannitol:

C6H8(OH)6 + H3BO3 C6H15O8B + H2O

The complex is titrated with sodium hydroxide solution to a pH of 6,3.

4. REAGENTS

4.1. Methyl red indicator solution

Dissolve 0,1 g of methyl red (C15H15N3O2) in 50 ml of ethanol (95 % in a 100 ml volumetric flask. Make up the volume to 100 ml with water. Mix thoroughly.

4.2. Diluted hydrochloric acid solution, about 0,5 mol/l

Mix 1 volume of hydrochloric acid HCl (d20 = 1,18 g/ml) with 20 volumes of water.

4.3. Sodium hydroxide solution, about 0,5 mol/l

Must be free of carbon dioxide. Dissolve 20 g of sodium hydroxide (NaOH) in pellet form in a 1 litre volumetric flask containing about 800 ml of boiled water. When the solution has cooled, make up to 1 000 ml with boiled water and mix thoroughly.

4.4. Standard sodium hydroxide solution, about 0,025 mol/l

Must be free of carbon dioxide. Dilute the 0,5 mol/l sodium hydroxide solution (4.3) 20 times with boiled water and mix thoroughly. The value of the solution expressed as boron (B) is to be determined (see Paragraph 9).

4.5. Boron calibration solution (100 µg/ml B)

Dissolve 0,5719 g of boric acid (H3BO3), weighed to the nearest 0,1 mg, in water in a 1,000 ml volumetric flask. Make up to volume with water and mix thoroughly. Transfer to a plastic bottle for storage in a refrigerator.

4.6. D-mannitol (C6H14O6) powder

4.7. Sodium chloride (NaCl)

5. APPARATUS

5.1. pH meter with glass electrode

5.2. Magnetic stirrer

5.3. 400 ml beaker with teflon rod

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Preparation of the boron solution

See Methods 10.1, 10.2 and, where appropriate, 10.3.

7. PROCEDURE

7.1. Test

Place in a 400 ml beaker (5.3) an aliquot (a) of the extract (6.1) containing 2 to 4 mg B. Add 150 ml of water.

Add several drops of the methyl red indicator solution (4.1).

In the case of extraction with Method 10.2, acidify by adding 0,5 mol/l hydrochloric acid (4.2) up to the point of change of the indicator solution, then add a further 0,5 ml of 0,5 mol/l hydrochloric acid (4.2).

After adding 3 g of sodium chloride (4.7), bring to boiling to drive off the carbon dioxide. Allow to cool. Place the beaker on the magnetic stirrer (5.2) and insert the precalibrated pH meter electrodes (5.1).

Adjust the pH to exactly 6,3, first with the 0,5 mol/l sodium hydroxide solution (4.3), then with the 0,025 mol/l solution (4.4).

Add 20 g of D-mannitol (4.6), dissolve completely and mix thoroughly. Titrate with the 0,025 mol/l sodium hydroxide solution (4.4) to pH 6,3 (at least 1 minute stability). Let X1 be the volume required.

8. BLANK SOLUTION

Prepare a blank solution by repeating the whole procedure from the preparation of solution stage, omitting only the fertilizer. Let X0 be the volume required.

9. BORON (B) VALUE OF THE SODIUM HYDROXIDE SOLUTION (4.4)

Pipette 20 ml (2,0 mg B) of the calibration solution (4.5), into a 400 ml beaker and add several drops of methyl red indicator solution (4.1). Add 3 g of sodium chloride (4.7) and the hydrochloric acid solution (4.2) up to the point of change of the indicator solution (4.1).

Make up the volume to about 150 ml and bring gradually to the boil so as to eliminate carbon dioxide. Allow to cool. Place the beaker on the magnetic stirrer (5.2), and insert the precalibrated pH meter electrodes (5.1). Adjust the pH to exactly 6,3, first with the 0,5 mol/l sodium hydroxide solution (4.3), then with the 0,025 mol/l solution (4.4).

Add 20 g of D-mannitol (4.6), dissolve completely and mix thoroughly. Titrate with the 0,025 mol/l sodium hydroxide solution (4.4) to pH 6,3 (at least 1 minute stability). Let V1 be the volume required.

Prepare a blank solution in the same way, substituting 20 ml of water for the calibration solution. Let V0 be the volume required.

The boron value (F) in mg/ml of the standard NaOH solution (4.4) is as follows:

F (in mg/ml) = 2 / (V1 - V0)

1 ml of exactly 0,025 mol/l sodium hydroxide solution corresponds to 0,27025 mg B.

10. EXPRESSION OF RESULTS

The percentage of boron in the fertilizer is given by:

B ( %) =

>REFERENCE TO A GRAPHIC>

.

where

B (%) is the percentage of boron in the fertilizer;

X1 is the volume, in ml, of the 0,025 mol/l sodium hydroxide solution (4.4); needed for the test solution

X0 is the volume, in ml, of the 0,025 mol/l sodium hydroxide solution (4.4); needed fot the blank solution

F is the boron (B) value, in mg/ml, of the 0,025 mol/l sodium hydroxide solution mol/l (4.4);

V is the volume, in ml, of the extract solution obtained in accordance with Method 10.1 or 10.2;

a is the volume, in ml, of the aliquot (7.1) taken from the extract solution (6.1);

M is the mass, in grams, of the test sample taken in accordance with Method 10.1 or 10.2.

Method 10.6 DETERMINATION OF COBALT IN FERTILIZER EXTRACTS BY THE GRAVIMETRIC METHOD WITH 1-NITROSO-2-NAPHTHOL

1. SCOPE

This document defines a procedure for determining cobalt in fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to extracts from samples of fertilizers obtained by Method 10.1 or Method 10.2 for which a declaration of cobalt content is required by Annex I E to this Regulation.

3. PRINCIPLE

Cobalt III combines with 1-nitroso-2-naphthol to give a red precipitate Co(C10H6ONO)3, 2H2O. After the cobalt present in the extract has been brought to the cobalt III state, the cobalt is precipitated in an acetic acid medium by a solution of 1-nitroso-2-naphthol. After filtration, the precipitate is washed and dried to constant mass and then weighed as Co (C10H6ONO)3, 2H2O.

4. REAGENTS

4.1. Hydrogen peroxide solution (H2O2, d20 = 1,11 g/ml) 30 %

4.2. Sodium hydroxide solution, about 2 mol/l

Dissolve 8 g of sodium hydroxide in pellet form in 100 ml of water.

4.3. Diluted hydrochloric acid solution, about 6 mol/l

Mix one volume of hydrochloric acid (d20 = 1,18 g/ml) with 1 volume of water.

4.4. Acetic acid (99,7 % CH3CO2H) (d20 = 1,05 g/ml)

4.5. Acetic acid solution (1: 2), about 6 mol/l

Mix one volume of acetic acid (4.4) with 2 volumes of water.

4.6. Solution of 1-nitroso-2-naphthol in 100 ml of acetic acid (4.4). Add 100 ml of lukewarm water. Mix thoroughly. Filter at once. The solution obtained must be used immediately

5. APPARATUS

5.1. Filter crucible P 16/ISO 4793, porosity 4, capacity 30 or 50 ml

5.2. Drying oven at 130 ± 2 °C

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Preparation of the cobalt solution

See Methods 10.1 or 10.2.

6.2. Preparation of the solution to be analyzed

Place an aliquot of the extract containing not more than 20 mg Co in a 400 ml beaker. If the extract is obtained according to Method 10.2, acidify with five drops of hydrochloric acid (4.3). Add about 10 ml of the hydrogen peroxide solution (4.1). Allow the oxidant to act in the cold state for 15 minutes, then make up to about 100 ml with water. Cover the beaker with a watch glass. Bring the solution to boiling point and allow to boil for about 10 minutes. Cool. Make alkaline with the sodium hydroxide solution (4.2) drop by drop until black cobalt hydroxide begins to precipitate.

7. PROCEDURE

Add 10 ml of acetic acid (4.4) and make up the solution with water to about 200 ml. Heat until boiling. Using a burette, add 20 ml of the 1-nitroso-2-naphthol solution (4.6) drop by drop, stirring constantly. Complete by vigorous stirring to make the precipitate coagulate.

Filter through a previously weighed filter crucible (5.1), taking care not to clog up the crucible. With this in mind, ensure that liquid is left above the precipitate throughout the filtration process.

Wash the beaker with dilute acetic acid (4.5) to remove all the precipitate, wash the precipitate on the filter with dilute acetic acid (4.5) and then three times with hot water.

Dry in a drying oven (5.2) at 130 ± 2 °C until constant mass is achieved.

8. EXPRESSION OF THE RESULTS

1 mg of Co (C10H6ONO)3, 2H2O precipitate corresponds to 0,096381 mg Co.

The percentage of Cobalt (Co) in the fertilizer is given by:

Co (%) = X × 0,0096381 ×

>REFERENCE TO A GRAPHIC>

where

X is the mass in mg of the precipitate;

V is the volume in ml of the extract solution obtained in accordance with Method 10.1 or Method 10.2;

a is the volume in ml of the aliquot taken from the last dilution;

D is the dilution factor of this aliquot;

M is the mass in g of the test sample.

Method 10.7 DETERMINATION OF COPPER IN FERTILIZER EXTRACTS BY THE TITRIMETRIC METHOD

1. SCOPE

This document defines a procedure for determining copper in fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to extracts from samples of fertilizers obtained by Method 10.1 or Method 10.2 for which a declaration of copper content is required by Annex IE to this Regulation.

3. PRINCIPLE

The cupric ions are reduced in an acidic medium with potassium iodide:

2Cu++ + 4I- ( 2CuI + I2

The iodine released in this way is titrated with a standard sodium thiosulphate solution in the presence of starch as an indicator in accordance with:

I2 + 2Na2S2O3 ( 2NaI + Na2S4O6

4. REAGENTS

4.1. Nitric acid (HNO3, d20 = 1,40 g/ml)

4.2. Urea [(NH2)2 C = 0]

4.3. Ammonium bifluoride (NH4HF2) solution 10 % w/v

Keep the solution in a plastic container.

4.4. Ammonium hydroxide solution (1 + 1)

Mix 1 volume of ammonia (NH4OH, d20 = 0,9 g/ml) with 1 volume of water.

4.5. Sodium thiosulphate standard solution

Dissolve 7,812 g of sodium thiosulphate pentahydrate (Na2S2O35H2O) with water in a 1 litre volumetric flask. This solution must be prepared so that 1 ml = 2 mg Cu. For stabilization, add several drops of chloroform. The solution must be kept in a glass container and protected from direct light.

4.6. Potassium iodide (KI)

4.7. Potassium thiocyanate (KSCN) solution (25 % w/v)

Keep this solution in a plastic flask.

4.8. Starch solution (about 0,5 %)

Place 2,5 g of starch in a 600 ml beaker. Add about 500 ml of water. Boil while stirring. Cool to ambient temperature. The solution has a short preservation period. Its preservation can be extended by adding about 10 mg of mercury iodide.

5. PREPARATION OF THE SOLUTION TO BE ANALYZED

Preparation of the copper solution

See Methods 10.1 and 10.2.

6. PROCEDURE

6.1. Preparation of the solution of titration

Place an aliquot portion of the solution containing not less thqn 20-40 mg Cu in a 500 ml Erlenmeyer flask.

Drive off any excess oxygen present by boiling briefly. Make up to a volume of about 100 ml water. Add 5 ml of nitric acid (4.1), bring to boiling and allow to boil for about half a minute.

Remove the Erlenmeyer flask from the heating apparatus, add about 3 g of urea (4.2) and resume boiling for about half a minute.

Remove from the heating apparatus and add 200 ml of cold water. Where necessary, cool the contents of the Erlenmeyer flask to ambient temperature.

Gradually add ammonia hydroxide solution (4.4) until the solution becomes blue, then add 1 ml in excess.

Add 50 ml of ammonium bifluoride solution (4.3) and mix.

Add 10 g of potassium iodide (4.6) and dissolve.

6.2. Titration of the solution

Place the Erlenmeyer flask on a magnetic stirrer. Insert the rod into the Erlenmeyer flask and adjust the stirrer to the desired speed.

Using a burette, add standard sodium thiosulphate solution (4.5) until the brown colour of the iodine released from the solution becomes less intense.

Add 10 ml of the starch solution (4.8).

Continue to titrate with the sodium thiosulphate solution (4.5) until the purple colour has almost disappeared.

Add 20 ml of the potassium thiocyanate solution (4.7) and continue titration until the violet blue colour has completely disappeared.

Note the volume for thiosulphate solution employed.

7. EXPRESSION OF RESULTS

1 ml of standard sodium thiosulphate solution (4.5) corresponds to 2 mg Cu.

The percentage of copper in the fertilizer is given by:

Cu (%) = X

>REFERENCE TO A GRAPHIC>

where

X is the volume in ml of the sodium thiosulphate solution used;

V is the volume in ml of the extract solution in accordance with Methods 10.1 and 10.2;

a is the volume in ml of the aliquot portion;

M is the mass in g of the test sample treated in accordance with Methods 10.1 and 10.2.

Method 10.8 DETERMINATION OF IRON IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY

1. SCOPE

This Method describes a procedure for determining iron in fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to extracts from samples of fertilizers obtained by Methods 10.1 and 10.2 for which a declaration of total and/or water-soluble iron is required by Annex IE to this Regulation.

3. PRINCIPLE

After suitable treatment and dilution of the extract, the iron content is determined by atomic absorption spectrometry.

4. REAGENTS

4.1. Hydrochloric acid solution, about 6 mol/l

See Method 10.4 (4.1).

4.2. Hydrochloric acid solution, about 0,5 mol/l

See Method 10.4 (4.2).

4.3. Hydrogen peroxide solution (30 % H2O2, d20 = 1,11 g/ml) free from micro-nutrients

4.4. Lanthanum salt solutions (10 g of La per litre)

See Method 10.4 (4.3).

4.5. Iron calibration solution

4.5.1. Iron stock solution (1 000 µg/ml)

In a 500 ml beaker, weigh to the nearest 0,1 mg, 1 g of pure iron wire, add 200 ml of 6 mol/l hydrochloric acid (4.1) and 15 ml of hydrogen peroxide solution (4.3). Heat on a hotplate until the iron is completely dissolved. When cool, transfer quantitatively to a 1 000 ml volumetric flask. Make up to volume with water and mix thoroughly.

4.5.2. Iron working solution (100 µg/ml)

Place 20 ml of the stock solution (4.5.1) in a 200 ml volumetric flask. Make up to volume with the 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly.

5. APPARATUS

Atomic absorption spectrometer: see Method 10.4 (5). The instrument must be fitted with a source of emitted radiation characteristic of iron (248,3 nm).

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Iron extract solution

See Methods 10.1 and/or 10.2 and, if appropriate, 10.3.

6.2. Preparation of the test solution

See Method 10.4 (6.2). The test solution must contain 10 % (v/v) of a lanthanum salt solution.

7. PROCEDURE

7.1. Preparation of blank solution

See Method 10.4 (7.1). The blank solution must contain 10 % (v/v) of the lanthanum salt solution used in 6.2.

7.2. Preparation of calibration solutions

See Method 10.4 (7.2).

For an optimum determination range of 0 to 10 µg/ml of iron, place 0, 2, 4, 6, 8 and 10 ml respectively of working solution (4.5.2) in a series of 100 ml volumetric flasks. If necessary adjust the hydrochloric acid concentration as closely as possible to that of the test solution. Add 10 ml of the lanthanum salt solution used in 6.2. Make up to volume with 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly. These solutions contain 0, 2, 4, 6, 8 and 10 µg/ml respectively of iron.

7.3. Determination

See Method 10.4 (7.3). Prepare the spectrometer (5) for measurement at a wavelength of 248,3 nm.

8. EXPRESSION OF RESULTS

See Method 10.4 (8).

The percentage of iron in the fertilizer is given by:

Fe (%) = [(xs - xb) × V × D] / (M × 104)

If Method 10.3 is used:

Fe (%) = [(xs - xb) × V × 2D] / (M × 104)

Where

Fe is the quantity of iron expressed as a percentage of the fertilizer;

xs is the concentration in µg/ml of the test solution (6.2);

xb is the concentration in µg/ml of the blank solution (7.1);

V is the volume in ml of extract obtained in accordance with Method 10.1 or 10.2;

D is the factor of dilution carried out in 6.2;

M is the mass in grams of the test sample taken in accordance with Method 10.1 or 10.2.

Calculation of the dilution factor D: if (a1), (a2), (a3), ..., (ai) and (a) are aliquot portions and (v1), (v2), (v3), ..., (vi) and (100) are the volumes in ml corresponding to their respective dilutions, the dilution factor D is given by:

D = (v1/a1) × (v2/a2) × (v3/a3) ×... × (vi/ai) × (100/a)

Method 10.9 DETERMINATION OF MANGANESE IN FERTILIZER EXTRACTS BY TITRATION

1. SCOPE

This Method describes a procedure for determining manganese in fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to extracts from samples of fertilizers obtained by Methods 10.1 and 10.2 for which a declaration of manganese is required by Annex I E to this.

3. PRINCIPLE

If chloride ions are present in the extract, they are driven off by boiling the extract with sulfuric acid. The manganese is oxidized by sodium bismuthate in a nitric acid medium. The permanganate formed is reduced by an excess of ferrous sulfate. This excess is titrated with a potassium permanganate solution.

4. REAGENTS

4.1. Concentrated sulfuric acid (H2SO4, d20 = 1,84 g/ml)

4.2. Sulfuric acid, about 9 mol/l

Carefully mix 1 volume of concentrated sulphuric acid (4.1) with 1 volume of water.

4.3. Nitric acid, 6 mol/l

Mix 3 volumes of nitric acid (HNO3, d20 = 1,40 g/ml) with 4 volumes of water.

4.4. Nitric acid, 0,3 mol/l

Mix 1 volume of 6 mol/l nitric acid with 19 volumes of water.

4.5. Sodium bismuthate (NaBiO3) (85 %).

4.6. Kieselguhr

4.7. Orthophosphoric acid, 15 mol/l (H3PO4, d20 = 1,71 g/ml)

4.8. Ferrous sulphate solution, 0,15 mol/l

Dissolve 41,6 g of ferrous sulphate heptahydrate (FeSO4, 7H2O) in a 1-litre volumetric flask.

Add 25 ml of concentrated sulphuric acid (4.1) and 25 ml phosphoric acid (4.7). Make up to 1,000 ml. Mix.

4.9. Potassium permanganate solution, 0,020 mol/l

Weigh out 3,160 g of potassium permanganate (KMnO4) to within 0,1 mg. Dissolve and make up to 1 000 ml with water.

4.10. Silver nitrate solution, 0,1 mol/l

Dissolve 1,7 g of silver nitrate (AgNO3) in water and make up to 100 ml.

5. APPARATUS

5.1. Filter crucible P16/ISO 4793, porosity 4, capacity 50 ml, mounted on a 500 ml filtration flask.

5.2. Magnetic stirrer

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Manganese extract solution

See Methods 10.1 and 10.2. If it is not known whether chloride ions are present, perform a test on the solution with one drop of the silver nitrate solution (4.10).

6.2. In the absence of chloride ions, place an aliquot of the extract containing 10 to 20 mg of manganese in a tall from 400 ml beaker. Bring to a volume of about 25 ml either by evaporation or by adding water. Add 2 ml of concentrated sulphuric acid (4.1)

6.3. If chloride ions are present, it is necessary to remove them as follows

Place an aliquot of the extract containing 10 to 20 mg of manganese in a tall form 400 ml beaker. Add 5 ml of 9 mol/l sulphuric acid (4.2). Under a fume hood, bring to boiling on a hot-plate and allow to boil until copious white fumes are released. Continue until the volume is reduced to about 2 ml (thin film of syrupy liquid at the bottom of the beaker). Allow to cool to ambient temperature.

Carefully add 25 ml of water and once again test for the presence of chlorides with one drop of the silver nitrate solution (4.10). If chlorides still remain, repeat the operation after adding 5 ml of 9 mol/l sulphuric acid (4.2).

7. PROCEDURE

Add 25 ml of 6 mol/l nitric acid (4.3) and 2,5 g of sodium bismuthate (4.5) to the 400 ml beaker containing the test solution. Stir vigorously for three minutes on the magnetic stirrer (5.2).

Add 50 ml of 0,3 mol/l nitric acid (4.4) and stir again. Filter in vacuo through a crucible (5.1), the bottom of which is covered with Keiselguhr (4.6). Wash the crucible several times with the 0,3 mol/l nitric acid (4.4) until a colorless filtrate is obtained.

Transfer the filtrate and the washing solution into a 500 ml beaker. Mix and add 25 ml of 0,15 mol/l ferrous sulphate solution (4.8). If the filtrate turns yellow after the addition of ferrous sulphate, add 3 ml of 15 mol/l orthophosphoric acid (4.7).

Using a burette, titrate the excess ferrous sulphate with 0,02 mol/l potassium permanganate solution (4.9) until the mixture turns pink, the colour remaining stable for one minute. Perform a blank test under the same conditions, omitting only the test sample.

Note

The oxidized solution must not come into contact with rubber.

8. EXPRESSION OF RESULTS

1 ml of 0,02 mol/l potassium permanganate solution corresponds to 1,099 mg of manganese (Mn).

The percentage of manganese in the fertilizer is given by:

Mn (%) where = (xb - xs) × 0,1099 ×

>REFERENCE TO A GRAPHIC>

Where

xb is the volume in ml of the permanganate used for the blank;

xs is the volume in ml of the permanganate used for the test sample;

V is the volume in ml of the extract solution in accordance with Methods 10.1 and 10.2;

a is the volume in ml of the aliquot portion taken from the extract;

M is the mass in g of the test sample.

Method 10.10 DETERMINATION OF MOLYBDENUM IN FERTILIZER EXTRACTS BY THE GRAVIMETRIC METHOD WITH 8-HYDROXYQUINOLINE

1. SCOPE

This document describes a procedure for determining molybdenum in fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to extracts from samples of fertilizers obtained by Methods 10.1 and 10.2 for which a declaration of molybdenum is required by Annex I E to this Regulation.

3. PRINCIPLE

The molybdenum level is determined by precipitation as molybdenyl oxinate under specific conditions.

4. REAGENTS

4.1. Sulphuric acid solution, approximately 1 mol/l

Carefully pour 55 ml of sulphuric acid (H2SO4, d20 = 1,84 g/ml) into a 1 litre volumetric flask containing 800 ml of water. Mix. After cooling, make up to one litre. Mix.

4.2. Diluted ammonia solution (1: 3)

Mix 1 volume of concentrated ammonia solution (NH4OH, d20 = 0,9 g/ml) with 3 volumes of water.

4.3. Diluted acetic acid solution (1: 3)

Mix 1 volume of concentrated acetic acid (99,7 % CH3COOH, d20 = 1,049 g/ml) with 3 volumes of water.

4.4. Solution of disodium salt of ethylene diamine tetraacetic acid (EDTA)

Dissolve 5 g of Na2EDTA in water in a 100 ml volumetric flask. Make up to the calibration mark and mix.

4.5. Buffer solution

In a 100 ml volumetric flask, dissolve 15 ml of concentrated acetic acid and 30 g of ammonium acetate in water. Make up to 100 ml.

4.6. 7-Hydroxyquinoline (oxine) solution

In a 100 ml volumetric flask, dissolve 3 g of 8-Hydroxyquinoline in 5 ml of concentrated acetic acid. Add 80 ml of water. Add the ammonia solution (4.2) drop by drop until the solution becomes cloudy and then add the acetic acid (4.3) until the solution becomes clear again.

Make up to 100 ml with water.

5. APPARATUS

5.1. Filter crucible P16/ISO 4793, porosity 4, capacity 30 ml

5.2. pH meter with glass electrode

5.3. Drying oven at 130 to 135 °C

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Preparation of the molybdenum solution. See Method 10.1 and Method 10.2

7. PROCEDURE

7.1. Preparation of the test solution

Place an aliquot portion containing 25 to 100 mg Mo in a 250 ml beaker. Make up the volume to 50 ml with water.

Adjust this solution to pH of 5 by adding the sulfuric acid solution (4.1) drop by drop. Add 15 ml of EDTA solution (4.4) and then 5 ml of buffer solution (4.5). Make up to about 80 ml with water.

7.2. Obtaining and washing the precipitate

Obtaining the precipitate

Heat the solution slightly. Stirring constantly, add the oxine solution (4.6). Continue the precipitation until formation of a deposit isnolonger observed. Add further reagent until the supernatant solution turns slightly yellow. A quantity of 20 ml should normally be sufficient. Continue to heat the precipitate slightly for two or three minutes.

Filtration and washing

Filter through a filter crucible (5.1). Rinse several times with 20 ml of hot water. The rinse water should gradually become colorless indicating that oxine is not longer present.

7.3. Weighing the precipitate

Dry the precipitate at 130 to 135 °C to constant mass (at least one hour).

Allow to cool in a desiccator and then weigh.

8. EXPRESSION OF THE RESULTS

1 mg of molybdenyl oxinate, MoO2(C9H6ON)2, corresponds to 0,2305 mg Mo.

The percentage of molybdenum in the fertilizer is given by:

Mo (%) = X × 0,02305 ×

>REFERENCE TO A GRAPHIC>

Where

X is the mass in mg of the molybdenyl oxinate precipitate;

V is the volume in ml of the extract solution in accordance with Methods 10.1 or 10.2;

a is the volume in ml of the aliquot taken from the last dilution;

D is the dilution factor of the aliquot;

M is the mass in g of the test sample.

Method 10.11 DETERMINATION OF ZINC IN FERTILIZER EXTRACTS BY ATOMIC ABSORPTION SPECTROMETRY

1. SCOPE

This Method describes a procedure for determining zinc in fertilizer extracts.

2. FIELD OF APPLICATION

This procedure is applicable to extracts from samples of fertilizers obtained by Methods 10.1 and 10.2 for which a declaration of zinc is required by Annex I E to this Regulation.

3. PRINCIPLE

After suitable treatment and dilution of the extracts, the zinc level is determined by atomic absorption spectrometry.

4. REAGENTS

4.1. Hydrochloric acid solution, about 6 mol/l

See Method 10.4 (4.1).

4.2. Hydrochloric acid solution, about 0,5 mol/l

See Method 10.4 (4.2).

4.3. Lanthanum salt solutions (10 g of La per litre)

See Method 10.4 (4.3).

4.4. Zinc calibration solutions

4.4.1. Zinc stock solution (1 000 µg/ml)

In a 1 000 ml volumetric flask, dissolve 1 g of zinc powder or flakes weighed to within 0,1 mg in 25 ml of 6 mol/l hydrochloric acid (4.1). When completely dissolved, make up to volume with water and mix thoroughly.

4.4.2. Zinc working solution (100 µg/ml)

In a 200 ml volumetric flask, dilute 20 ml of the stock solution (4.4.1) in 0,5 mol/l hydrochloric acid solution (4.2). Make up to a volume with the 0,5 mol/l hydrochloric acid solution and mix thoroughly.

5. APPARATUS

Atomic absorption spectrometer.

See Method 10.4 (5). The apparatus must be fitted with a source of lines characteristic of zinc (213,8 nm). The spectrometer must allow background correction to be made.

6. PREPARATION OF THE SOLUTION TO BE ANALYZED

6.1. Zinc extract solution

See Method 10.1 and/or 10.2.

6.2. Preparation of the test solution

See Method 10.4 (6.2). The test solution must contain 10 % by volume of lanthanum salt solution (4.3).

7. PROCEDURE

7.1. Preparation of the blank solution

See Method 10.4 (7.1). The blank solution must contain 10 % by volume of the lanthanum salt solution used in 6.2.

7.2. Preparation of the calibration solutions

See Method 10.4 (7.2). For an optimum interval of 0 to 5 µg/ml of zinc, place 0, 0,5, 1, 2, 3, 4 and 5 ml, respectively, of the working solution (4.4.2) in a series of 100 ml volumetric flasks. Where necessary, adjust the concentration of hydrochloric acid to bring it as close as possible to that of the test solution. Add 10 ml of the lanthanum salt solution used in (6.2) to each volumetric flask. Make up to 100 ml with the 0,5 mol/l hydrochloric acid solution (4.2) and mix thoroughly.

These solutions contain, respectively, 0, 0,5, 1, 2, 3, 4 and 5 µg/ml of zinc.

7.3. Determination

See Method 10.4 (7.3). Prepare the spectrometer (5) for measurements at a wavelength of 213,8 nm.

8. EXPRESSION OF RESULTS

See Method 10.4 (8).

The percentage of zinc in the fertilizer is given by:

Zn (%) = [(xs - xb) × V × D] / (M × 104)

If Method 10.3 has been used:

Zn (%) = [(xs - xb) × V × 2D] / (M × 104)

Where

Zn is the quantity of zinc expressed as a percentage of the fertilizer;

xs is the concentration in µg/ml of the test solution;

xb is the concentration in µg/ml of the blank solution;

V is the volume in ml of the extract solution obtained in accordance with Method 10.1 or 10.2;

D is the factor corresponding to the dilution performed in (6.2);

M is the mass in g of the test sample taken in accordance with Method 10.1 or 10.2.

Calculation of the dilution factor D:

where (a1), (a2), (a3), ..., (ai) and (a) are successive aliquot portions and (v1), (v2), (v3), ..., (vi) and (100) are the volumes in ml corresponding to their respective dilutions, the dilution factor D is given by:

D = (v1/a1) × (v2/a2) × (v3/a3) ×... × (vi/ai) × (100/a)

ANNEX V

A. List of documents to be consulted by manufacturers or their representatives in order to compile a technical file for a new type of fertilizers to be added to annex I of this regulation

1. Guide to the compilation of a technical file on application to designate fertilizers "EC FERTILIZER".

Official Journal of the European Communities, No. C 138, of 20.5.1994, p. 4.

2. Commission Directive 91/155/EEC of 5 March 1991 on defining and laying down the detailed arrangements for the system of specific information relating to dangerous preparations in implementation of Article 10 of Directive 88/379/EEC.

Official Journal of the European Communities, No. L 76/35, of 22.3.1991, p. 35.

3. Commission Directive 93/112/EC of 10 December 1993 on amending Commission Directive 91/155/EEC defining and laying down detailed arrangements for the system of specific information relating to dangerous preparations in implementation of Article 10 of Council Directive 88/379/EEC.

Official Journal of the European Communities, No. L 314, of 16.12.1993, p. 38.

B. Standards of accreditation concerning the laboratories that are competent and authorised to provide the necessary service for checking compliance of EC fertilizers with the requirements of this Regulation and its annexes.

1. Standard applicable at the level of the laboratories:

EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories.

2. Standard applicable at the level of the accreditation bodies:

EN 45003, Calibration and testing laboratory accreditation system, general requirements for operation and recognition.

IMPACT ASSESSMENT FORM DRAFT OF THE IMPACT OF THE PROPOSAL ON BUSINESS WITH SPECIAL REFERENCE TO SMALL AND MEDIUM-SIZED ENTERPRISES (SMEs)

Title of proposal

Regulation of the European Parliament and of the Council relating to fertilizers

Document reference number

n/a

The proposal

1. Taking account of the principle of subsidiarity, why is Community legislation necessary in this area and what are its main aims*

The Directives on EC mineral fertilizers established since 1976 a single market for this product. Up to then only national regulations in Member States applied, making it necessary for a manufacturer to undergo in each Member States individual authorisation procedures in order to be permitted to place the product on the markets. These national regulations still exist, but do not apply for EC fertilizers. Since 1976 altogether 18 Directives on EC fertilizers where adopted and in 1997 it was decided to "SLIM" the legislation by recasting all the Directives into one and thereby updating the provisions where appropriate.

The impact on business

2. Who will be affected by the proposal*

- which sectors of business* Mainly large chemical companies which produce mineral fertilizers, and importers of mineral fertilizers from outside the EU.

- which sizes of business* (what is the concentration of small and medium-sized firms*) The EC fertilizer market is dominated by large chemical companies, with European firms supplying 70% of the fertilizer demand in the EU. Most of the rest is supplied by importers. SME's have only a negligible part of the market.

- are there particular geographical areas of the Community where these businesses are found* Fertilizer companies are fairly evenly distributed across the EU with main players in Finland, UK, Germany, France, Belgium, Spain.

3. What will business have to do to comply with the proposal*

The proposed regulation will be binding in its entirety in all Member States and many of the new technical aspects take into account the changes that products have undergone over the years. No major changes in industry will be required.

4. What economic effects is the proposal likely to have*

- on employment: not measurable

- on investment and the creation of new businesses: not measurable

- on the competitiveness of businesses: The proposed regulation is easier to read and understand than the old 18 Directives, in particular because no transposition will be required. It also sets the scene for a future extension of the legislation towards other, not yet included fertilizer types. This might encourage business, particularly SME's to make proposals for more specialised EC fertilizers.

5. Does the proposal contain measures to take account of the specific situation of small and medium-sized firms *(reduced or different requirements etc)

SME's in this sector are mostly involved in the blending of fertilizers. In this proposed regulation provisions have been included to specifically label blended fertilizers. However the benefit will be more for the final customer (e.g. farmer).

Consultation

6. List the organisations, which have been consulted about the proposal and outline their main views.

The proposal underwent a lengthy and intensive consultation period in the Commission's fertilizer working group, which besides experts from Member States included also experts from the European Fertilizer Manufacturer Association, EFMA, and the European Fertilizer Importer Association, EFIA. Both organisations where involved in the drafting exercise, particularly concerning the technical details. They are particularly positive concerning the overall structure of the proposed regulation, making it easier for manufacturers to understand and apply the provisions.