1、BSI Standards PublicationBS EN 13368-1:2014Fertilizers Determination ofchelating agents in fertilizersby chromatographyPart 1: Determination of EDTA, HEEDTA andDTPA by ion chromatographyBS EN 13368-1:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 13368-1:2
2、014.It supersedes BS EN 13368-1:2001 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee CII/37, Fertilisers and related chemicals.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not pur
3、port to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 77579 6ICS 65.080Compliance with a British Standard cannot confer immunity fromlegal obligations.T
4、his British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 January 2014.Amendments issued since publicationDate Text affectedBS EN 13368-1:2014EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 13368-1 January 2014 ICS 65.080 Supersedes EN 13368-1:20
5、01English Version Fertilizers - Determination of chelating agents in fertilizers by chromatography - Part 1: Determination of EDTA, HEEDTA and DTPA by ion chromatography Engrais - Dtermination des agents chlatants dans les engrais par chromatographie - Partie 1: Dtermination du EDTA, HEEDTA et DTPA
6、par chromatographie ionique Dngemittel - Bestimmung von Chelatbildnern in Dngemitteln mit Chromatographie - Teil 1: Bestimmung von EDTA, HEEDTA und DTPA mit IonenchromatographieThis European Standard was approved by CEN on 16 November 2013. CEN members are bound to comply with the CEN/CENELEC Intern
7、al 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 CEN-CENELEC Management Centre or to any C
8、EN 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 CEN-CENELEC Management Centre has the same status as the official vers
9、ions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
10、Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2014 CEN All rights of exploitat
11、ion in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13368-1:2014 EBS EN 13368-1:2014EN 13368-1:2014 (E) 2 Contents Page Foreword 3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Principle 4 5 Interferences 4 6 Reagents .5 7 Apparatus .6 8 Sampli
12、ng and sample preparation .7 9 Procedure .7 9.1 Preparation of the test solution 7 9.2 Preparation of the standard solutions .7 9.3 Chromatographic analysis 7 10 Expression of results 8 11 Precision .8 12 Test report 9 Annex A (informative) Complete names of chelating agents . 10 Annex B (informativ
13、e) Chromatogram 11 Bibliography . 12 BS EN 13368-1:2014EN 13368-1:2014 (E) 3 Foreword This document (EN 13368-1:2014) 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
14、 national standard, either by publication of an identical text or by endorsement, at the latest by July 2014, and conflicting national standards shall be withdrawn at the latest by July 2014. Attention is drawn to the possibility that some of the elements of this document may be the subject of paten
15、t rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 13368-1:2001. The following modifications have been made: a) the title of the European Standard revised; b) referenced European Standards on vocabulary added to Claus
16、e 2; c) Clause 3 Terms and definitions added; d) the sampling method is not part of the standard, informative reference to EN 1482-1 added; e) Annex A: complete names of chelating agents technical revised; f) Bibliography revised; g) editorially revised. According to the CEN-CENELEC Internal Regulat
17、ions, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Ital
18、y, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 13368-1:2014EN 13368-1:2014 (E) 4 1 Scope This European Standard specifies a method for the chromatographic determination of t
19、he total amount of each of the individual chelating agents EDTA, HEEDTA, and DTPA in fertilizers containing one or more 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 distingu
20、ish between the free form and the metal bound form of the chelating agents. NOTE EDTA, HEEDTA and DTPA are abbreviations used in this European Standard for the sake of simplicity. For complete names see Annex A. This method applies to fertilizers containing chelates of one or more of the following m
21、icro-nutrients: cobalt, copper, iron, manganese, zinc and with a mass fraction of at least 0,1 %. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited a
22、pplies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1482-2, Fertilizers and liming materials - Sampling and sample preparation - Part 2: Sample preparation EN 12944-1:1999, Fertilizers and liming materials and soil improvers - Vocabula
23、ry - Part 1: General terms EN 12944-2:1999, Fertilizers and liming materials and soil improvers - Vocabulary - Part 2: Terms relating to fertilizers EN ISO 3696, Water for analytical laboratory use - Specification and test methods (ISO 3696) 3 Terms and definitions For the purposes of this document,
24、 the terms and definitions given in EN 12944-1:1999 and EN 12944-2:1999 apply. 4 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 separat
25、ion is based on anion exchange, by elution with a nitrate acetate solution. The detection is based on UV photometry at 330 nm, after post-column reaction with diluted perchloric acid. 5 Interferences Several substances can interfere, to a degree largely dependent on the type of column used. With the
26、 column described in 7.2, 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 confi
27、rmed by standard addition. BS EN 13368-1:2014EN 13368-1:2014 (E) 5 b) Solutions having high concentrations of salts can also create a large signal at the void volume, poorly resolved from the HEEDTA peak. c) High concentrations of nitrate, carbonate, sulfate, and phosphate do not interfere. On the o
28、ther hand, large amounts of chloride create a negative fronting peak poorly resolved from the DTPA peak, and altering its peak shape. d) Compounds, related to the group of polyamino polycarboxylic acids can interfere. While signals for o,o EDDHA, o,o EDDHMA, and EDDHSA are not detected, relatively w
29、eak signals are observed for NTA and CDTA. Under some conditions NTA may coelute with HEEDTA or EDTA. NOTE EDDHA, EDDHMA, EDDHSA, NTA and CDTA are abbreviations used in this European Standard for the sake of simplicity. For complete names see Annex A. e) No signals have been detected for the followi
30、ng complexing agents: citrate, oxalate, tartrate, phthalate, and 20 naturally occurring amino acids. 6 Reagents 6.1 Reagents of recognized analytical grade and water conforming to EN ISO 3696, degassed by boiling before use. 6.2 Nitric acid, c(HNO3) = 7,2 mol/l. Nitric acid, diluted 1 + 1 with water
31、. 6.3 Sodium hydroxide solution, c(NaOH) = 0,5 mol/l. Dissolve 20 g of NaOH in pellet form in a 1 l volumetric flask with water. Dilute to the mark and homogenize. 6.4 EDTA stock solution, c(EDTA) = 2 mmol/l. Dissolve 372 mg of the disodium dihydrogen salt of ethylene diamine tetraacetic acid dihydr
32、ate in 400 ml of water in a 500 ml volumetric flask. After dissolution, dilute to the mark with water and homogenize. Store the solution in a plastic bottle. 6.5 HEEDTA stock solution, c(HEEDTA) = 2 mmol/l. Dissolve 380 mg of the trisodium salt of hydroxyethyl ethylene diamine triacetic acid dihydra
33、te in 400 ml of water in a 500 ml volumetric flask. After dissolution, dilute to the mark with water and homogenize. Store the solution in a plastic bottle. 6.6 DTPA stock solution, c(DTPA) = 2 mmol/l. Dissolve 393 mg of diethylene triamine pentaacetic acid in 10 ml of NaOH (6.3) in a 50 ml beaker.
34、After dissolution, transfer quantitatively into a 500 ml volumetric flask, dilute to the mark with water and homogenize. Store the solution in a plastic bottle. 6.7 EDTA/HEEDTA/DTPA standard mixtures. Into a set of three volumetric flasks of 100 ml, pipette respectively 2,5 ml, 5 ml and 10 ml of eac
35、h stock solution of 2 mmol/l (6.4, 6.5 and 6.6). Dilute to the mark with water and homogenize. These solutions contain a mixture of EDTA, HEEDTA and DTPA, in concentrations of respectively 0,05 mmol/l, 0,1 mmol/l and 0,2 mmol/l. They should be used within two days. BS EN 13368-1:2014EN 13368-1:2014
36、(E) 6 6.8 Eluent nitrate (50 mmol/l) and acetate (50 mmol/l). Dissolve 4,10 g of anhydrous sodium acetate (NaCH3COO) in a mixture of 800 ml of water and 6,95 ml of nitric acid (6.2) in a 1 l volumetric flask. Dilute to the mark with water and homogenize. Adjust the pH of the eluent to 2,75 0,20. Bef
37、ore use, filter the solution through a 0,45 m membrane filter (7.3). NOTE The concentration of the eluent influences the speed and the efficiency of the separation, which can be carried out with eluent concentrations varying between 25 mmol/l and 75 mmol/l of nitrate and acetate. At low concentratio
38、ns, an improved separation between the void signal, the HEEDTA and the EDTA peaks can be obtained, while at high concentrations a better DTPA peak shape is observed. 6.9 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 o
39、f nitric acid (6.2) in a 1 l volumetric flask. Dilute to the mark with water and homogenize. Store the solution in a plastic bottle. NOTE Nitric acid is added in order to stabilize the solution and to allow the complete replacement of other chelated micro-nutrients by iron(III). 6.10 Perchloric acid
40、 solution, 2 %. Dilute 29 ml of perchloric acid (70 % HClO4, = 1,67 g/ml) to 1 l with water. 7 Apparatus Usual laboratory equipment, glassware, and the following: 7.1 Rotary shaker, capable of operating at a rotational speed of about 35 min1to 45 min1. 7.2 Chromatograph, equipped with: a) an isocrat
41、ic pump delivering the eluent (6.8) at a flow rate of 0,5 ml/min; b) an injection valve with an injection loop of about 50 l; c) an anion exchange separator column 10 m particles 2 % substrate x linking 100 mmolccapacity (per column) alkyl quaternary ammonium medium high (hydrophobic)1); NOTE 1 The
42、column mentioned in c) is not exclusive. Any anion exchange column with comparable capacity, hydrophobicity, and selectivity can probably be used. NOTE 2 Columns can, in their native state, exhibit some sensitivity towards various anions (e.g. nitrate, sulfate, phosphate) which can disappear after t
43、reatment 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 (6.9), followed by equilibration under eluent flow for at least 6 h. After many injections, especially of products having complex matrices, the co
44、lumn may lose some of the capacity and the separating efficiency. Substances like phenolic compounds (e.g. o,o EDDHA, 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 clean
45、ing instructions are consulted for the suitable cleaning procedure. 1) A combination of IonPac AS 7 separator and Ion Pac AG 7 guard column from Dionex Co, Sunnyvale, CA USA, or equivalent are examples of suitable products available commercially. This information is given for the convenience of user
46、s of this European Standard and does not constitute an endorsement by CEN of these products. BS EN 13368-1:2014EN 13368-1:2014 (E) 7 The injection of un-dissolved matter severely decreases the lifetime of the column. Solutions should always be allowed to equilibrate, and then filter through a 0,2 m
47、membrane filter before injection. d) a post-column reagent delivery module, delivering the reagent (6.10) at a flow rate between 0,5 ml/min and 0,6 ml/min; NOTE 3 The post-column reagent stabilizes the eluting ferric chelates and suppresses the signal of some possibly interfering substances. For the
48、 analysis of samples with simple matrices, the post column reaction can be considered as superfluous. e) an UV/VIS detector with a 330 nm filter, output range set at an absorbance of 0,1; NOTE 4 Ferric chelates of EDTA, HEEDTA, and DTPA have a useful spectral absorbance between 250 nm and 350 nm. Th
49、e absorbance at 254 nm offers a better sensitivity, but also produces a noisier background, more sensitive to interferences. f) an integrator. 7.3 Membrane filters, micro membrane filters, resistant to aqueous solutions, with porosity of respectively 0,45 m and 0,2 m. 8 Sampling and sample preparation Sampling is not part of the method specified in this document. A recommended sampling method is given in EN 1482-1. Sample preparation shall be carried out in accordance with EN 1482-2. For the size reduction of samples with a high amount of chelating a
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