BS-EN-13368-2-2001.pdf

BRITISH STANDARD BS EN 13368-2:2001 Fertilizers Determination of chelating agents in fertilizers by ion chromatography Part 2: EDDHA and EDDHMA The European Standard EN 13368-2:2001 has the status of a British Standard ICS 65.080 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 01:39:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 13368-2:2001 This British Standard, having been prepared under the direction of the Sector Committee for Materials and Chemicals, was published under the authority of the Standards Committee and comes into effect on 15 May 2001 © BSI 05-2001 ISBN 0 580 37286 3 National foreword This British Standard is the official English language version of EN 13368-2:2001. The UK participation in its preparation was entrusted to Technical Committee CII/37, Fertilizers and related chemicals, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 11 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 01:39:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM EN 13368-2 January 2001 ICS 65.080 English version Fertilizers - Determination of chelating agents in fertilizers by ion chromatography - Part 2: EDDHA and EDDHMA Engrais - Détermination des agents chélatants dans les engrais par chromatographie ionique - Partie 2: EDDHA et EDDHMA Düngemittel - Bestimmung von Chelatbildnern in Düngemitteln durch lonenchromatographie - Teil 2: EDDHA und EDDHMA This European Standard was approved by CEN on 1 January 2001. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels © 2001 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13368-2:2001 E Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 01:39:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 2 EN 13368-2:2001 Content Foreword3 1Scope 4 2Normative references 4 3Principle4 4Interferences.4 5Reagents.5 6Apparatus .6 7Preparation of the sample.6 8Procedure .7 9Expression of results 7 10Precision.8 11Test report 8 Annex A (informative) Complete names of chelating agents 9 Annex B (informative) Chromatogram10 Bibliography11 Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 01:39:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 3 EN 13368-2:2001 Foreword This European Standard has been prepared by Technical Committee CEN/TC 260 “Fertilizers and liming materials“, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by July 2001, and conflicting national standards shall be withdrawn at the latest by July 2001. EN 13368 consists of two parts dealing with the quantitative determination of chelating agents in fertilizers by ion chromatography : -Part 1 : EDTA, HEDTA and DTPA -Part 2 : EDDHA and EDDHMA The annexes A and B are informative. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 01:39:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 4 EN 13368-2:2001 1 Scope This method describes the procedure for the ion chromatographic determination of the total amount of each of the individual ortho-ortho isomer of the chelating agents EDDHA and EDDHMA in fertilizers containing one or both of these substances. The method allows the identification and the determination of the total water soluble fraction of each of these chelating agents. It does not allow to distinguish between the free form and the metal bound form of the chelating agents. NOTE 1EDDHA and EDDHMA are abbreviations used in this standard for the sake of simplicity. For complete names see annex A. NOTE 2The substances EDDHA and EDDHMA exist under several different isomeric forms. Positional isomers (ortho, meta, and para forms) as well as stereo isomers (meso and dl forms) are known. This method applies to fertilizers containing chelates of one or more of the following micro-nutrients: cobalt, copper, iron, manganese, zinc and with a mass fraction of at least 0,1 %. NOTE 3At present, analytically pure standards only exist for ortho-ortho EDDHA. All other substances being unavailable as a standard, the influence of their eventual presence in the samples (with respect to the sensitivity and the selectivity of this method) has not been studied. For EDDHMA, the method has been developed with samples of iron EDDHMA of uncertain purity and composition, any standard product being unavailable. NOTE 4In the chromatographic conditions of this method, the stereo isomers of EDDHA and EDDHMA are eluting together as a single peak. Using an eluent with a lower exchange strength, the meso and the dl forms of EDDHA and EDDHMA can be separated. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments). EN 1482, Sampling of solid fertilizers and liming materials EN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696 : 1987) 3 Principle The micro-nutrients associated with the chelating agents present in an aqueous extract of the sample are replaced by iron (III). The iron chelates are separated and determined by ion chromatography. The separation is based on anion exchange, by elution with an acidified sulfate solution. The detection is based on photometry at 520 nm. 4 Interferences Some substances can interfere, to a degree largely dependent on the type of column used. With the column described in 6.2, the following phenomena have been observed. a)Injection of solutions having high concentrations of salts can cause shifts in the retention times, mostly decreasing the retention when compared to the standard solutions. In these cases, the identity of the peaks can be confirmed by standard addition. b)High concentrations of chloride, nitrate, carbonate, and sulfate do not interfere. On the other hand, the resolution and the sensitivity of the chelating agents are severely depressed in the presence of high amounts of phosphate. c)Compounds, related to the group of polyamino polycarboxylic acids, do not interfere. No signals are detected for EDTA, HEDTA, NTA, CDTA, and EDDHSA. DTPA gives a weak non-interfering signal close to the void volume. Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 01:39:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 5 EN 13368-2:2001 NOTE EDTA, HEDTA, NTA, CDTA, EDDHSA and DTPA are abbreviations used in this standard for sake of simplicity. For complete names see annex A. d)No signals have been detected for the following complexing agents : citrate, oxalate, tartrate, phthalate, and 20 naturally occuring amino acids. 5 Reagents 5.1 General a) all reagents should be of recognized analytical grade ; b) all water should conform to EN ISO 3696 and be degassed by boiling before use. 5.2 Nitric acid, c(HNO3) = 7,2 mol/l Nitric acid, diluted 1 + 1 with water. 5.3 Sodium hydroxide solution, c(NaOH) = 0,5 mol/l Dissolve 20 g of NaOH in pellet form in a 1 litre volumetric flask with water. Dilute to the mark and homogenize. 5.4 Sulfuric acid solution, c(H2S04) = 0,1 mol/l Dilute 2,75 ml of sulfuric acid (96 % H2S04 , ? = 1,84 g/ml) to 500 ml with water. 5.5 EDDHA solution, c(EDDHA) = 2 mmol/l Dissolve 72 mg of ethylenediamine-di(o-hydroxyphenyl)acetic acid (EDDHA) in 2 ml of NaOH (5.3) in a 30 ml beaker. After dissolution, transfer quantitatively into a 100 ml volumetric flask, dilute to the mark with water and homogenize. Prepare the solution immediately before use. 5.6 EDDHMA solution, c(EDDHMA) = 2 mmol/l Dissolve 78 mg of ethylenediamine-di(o-hydroxy-p-methylphenyl)acetic acid (EDDHMA) in 2 ml of NaOH (5.3) in a 30 ml beaker. After dissolution, transfer quantitatively into a 100 ml volumetric flask, dilute to the mark with water and homogenize. Prepare the solution immediately before use. NOTEIn the absence of a pure standard product, a solution of maximally 2 mmol/l can be prepared by dissolving 88 mg of an iron EDDHMA sample in 100 ml of water. For a sample of 100 % pure Fe-EDDHMA, a concentration of exactly 2 mmol/m is obtained. 5.7 EDDHA/EDDHMA standard mixtures Into a set of 3 volumetric flasks of 100 ml, pipette respectively 2,5 ml, 5 ml and 10 ml of each solution of 2 mmol/l (5.5 and 5.6). Dilute to the mark with water and homogenize. These solutions contain a mixture of EDDHA and EDDHMA, in concentrations of respectively 0,05 mmol/l, 0,1 mmol/l and 0,2 mmol/l. Prepare the solution immediately before use. 5.8 Eluent sulfate (50 mmol/l), acidified Dissolve 7,10 g of anhydrous sodium sulfate (Na2S04) in a mixture of 800 ml of water and 9 ml of sulfuric acid solution (5.4) in a 1 litre volumetric flask. Dilute to the mark with water and homogenize. Adjust the pH of the eluent to 3,15 ± 0,20. Before use, filter the solution through a 0,45 µm membrane filter (6.3). 5.9 Iron (III) nitrate solution Dissolve 5 g of ferric nitrate nonahydrate ( Fe(NO3)3 · 9H2O) in a mixture of 800 ml of water and 21 ml of nitric acid (5.2) in a 1 litre volumetric flask. Dilute to the mark with water and homogenize. Store in a plastics bottle. Licensed Copy: sheffieldun sheffieldun, na, Mon Oct 30 01:39:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 6 EN 13368-2:2001 NOTENitric acid is added in order to stabilize the solution and to allow the complete replacement of other chelated micro- nutrients by iron (III). 6 Apparatus Usual laboratory equipment, glassware, and : 6.1 Rotary shaker Rotary shaker capable of operating at a rotational speed of about 35 min-1 to 45 min-1. 6.2 Ion chromatograph Ion chromatograph equipped with : a) an isocratic pump delivering the eluent (5.8) at a flow rate of 1 ml/min ; b) an injection valve with an injection loop of about 50 µl. NOTE 1An automatic injection valve can malfunction, and its use is not recommended because the column, described in item c), is a short guard column creating a low backpressure. c)an anion exchange separator column with reduced length 10 µm particles 2 % substrate x linking 100 meq capacity (per column) alkyl quaternary ammonium medium high (hydrophobicity)1) ; NOTE 2The column mentioned in c) is not exclusive. Any anion exchange column with comparable capacity, hydrophobicity, and selectivity can probably be used ; NOTE 3columns can, in their native state, exhibit some sensitivity towards various anions (e.g. chloride, nitrate, sulfate, phosphate) which can disappear after treatment with excess iron. It can be necessary to precondition the column prior to its use by repeated injections, at least 10, of the iron (III) solution (5.9), followed by equilibration under eluent flow for at least 6 h ; NOTE 4after many injections, especially of products having complex matrices, the column may lose some of its capacity and its separating efficiency. Substances like humic acids can be strongly adsorbed on the column particles. Suspended and colloidal matter can block the column entrance and disturb the eluent flow. The column manufacturer cleaning instructions are consulted for the suitable cleaning procedure. Generally the column efficiency can be restored by rinsing the column in the reverse direction with 0,5 mol/l of sodium hydroxide, then with water, then with 0,5 mol/l nitric acid, and finally with the eluent for equilibration ; NOTE 5the injection of undissolved matter severely decreases the lifetime of the column. Solutions should always be allowed to equilibrate, and then filter through a 0,2 µm membrane filter before injection ; d)a UV/VIS detector with a 520 nm filter, output range set at an absorbance of 0,1 ; e)an integrator. 6.3 Membrane filters Micromembrane filters resistent to aqueous solutions, with porosity of respectively 0,45 µm and 0,2 µm. 7 Preparation of the sample Prepare the sample according to EN 1482. NOTE 1Sample may also be prepared according to method 1 (see 1 of bibliography). NOTE 2For the size reduction of samples with a high amount of chelating agents, it is not recomme