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1、DRAFT FOR DEVELOPMENT DD CEN/TS 15451:2006 Fertilizers Determination of chelating agents Determination of iron chelated by EDDHSA by ion pair chromatography ICS 65.080 ? Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:28:38 GMT+00:00 2006, Uncontrolled Copy,
2、(c) BSI DD CEN/TS 15451:2006 This Draft for Development was published under the authority of the Standards Policy and Strategy Committee on 29 December 2006 BSI 2006 ISBN 0 580 49830 1 National foreword This Draft for Development was published by BSI. It is the UK implementation of CEN/TS 15451:2006
3、. This publication is not to be regarded as a British Standard. It is being issued in the Draft for Development series of publications and is of a provisional nature. It should be applied on this provisional basis, so that information and experience of its practical application can be obtained. Comm
4、ents arising from the use of this Draft for Development are requested so that UK experience can be reported to the European organization responsible for its conversion to a European standard. A review of this publication will be initiated not later than 3 years after its publication by the European
5、organization so that a decision can be taken on its status. Notification of the start of the review period will be made in an announcement in the appropriate issue of Update Standards. According to the replies received by the end of the review period, the responsible BSI Committee will decide whethe
6、r to support the conversion into a European Standard, to extend the life of the Technical Specification or to withdraw it. Comments should be sent to the Secretary of the responsible BSI Technical Committee at British Standards House, 389 Chiswick High Road, London W4 4AL. The UK participation in it
7、s preparation was entrusted to Technical Committee CII/37, Fertilisers and related chemicals. A list of organizations represented on CII/37 can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for
8、its correct application. Amendments issued since publication Amd. No. DateComments Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:28:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI TECHNICAL SPECIFICATION SPCIFICATION TECHNIQUE TECHNISCHE SPEZIFIKATION CEN/TS
9、15451 November 2006 ICS 65.080 English Version Fertilizers - Determination of chelating agents - Determination of iron chelated by EDDHSA by ion pair chromatography Engrais - Dosage des agents chlatants - Dosage du fer chlat par EDDHSA par chromatographie dappariement dions Dngemittel - Bestimmung v
10、on Chelatbildnern - Bestimmung von Eisen-chelatisiertem EDDHSA mit Ionen- Paarchromatographie This Technical Specification (CEN/TS) was approved by CEN on 27 May 2006 for provisional application. The period of validity of this CEN/TS is limited initially to three years. After two years the members o
11、f CEN will be requested to submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard. CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available promptly at national level in a
12、n appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached. CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Den
13、mark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALIS
14、ATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2006 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. CEN/TS 15451:2006: E Licensed Copy: London South Bank University, London South Bank Univer
15、sity, Sat Dec 30 06:28:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 Contents Page Foreword3 1 Scope 4 2 Normative references4 3 Principle4 4 Interferences 4 5 Reagents.4 6 Apparatus .6 7 Sampling and sample preparation.6 8 Procedure .7 9 Expression of the result8 10 Precision for Fe3+/EDDHSA.8 11
16、 Test report9 Annex A (informative) Chromatogram for Fe3+/EDDHSA 10 Annex B (informative) Spectra UV-visible for Fe3+/EDDHSA 11 Annex C (informative) Results of the inter-laboratory tests.12 Annex D (informative) Complete names of chelating agents .14 Bibliography15 CEN/TS 15451:2006 Licensed Copy:
17、London South Bank University, London South Bank University, Sat Dec 30 06:28:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 3 Foreword This document (CEN/TS 15451:2006) has been prepared by Technical Committee CEN/TC 260 “Fertilizers and liming materials”, the secretariat of which is held by DIN. Thi
18、s document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to announce this Technical Specification: Austria
19、, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. CEN/TS 15451:2006 Lice
20、nsed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:28:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4 1 Scope This Technical Specification specifies a method for the chromatographic determination of the total amount of iron chelated by EDDHSA in commercial products.
21、 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. prEN 1482-2, Fertilizers
22、and liming materials Sampling and sample preparation Part 2: Sample preparation EN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696:1995) 3 Principle The iron chelates are determined by ion-pair high-performance liquid chromatography. When an iron chelate (anion
23、) is added to a polar fluid (eluent), containing a large cation (ion-pair reagent), an ion pair is formed. This ion pair is retained by an apolar solid phase (stationary phase). The strength of the retention depends on the molecular size and its acidity. Each iron chelate presents a characteristic r
24、etention time and a characteristic spectrum depending on the chelating agent, and it is separated from the other substances present in the sample. The separation is carried out on a reverse phase silica column and an aqueous solution of TBA+ (tetrabutylammonium) and acetonitrile as eluent. The detec
25、tion is based on photometry at 480 nm. For Fe3+/EDDHSA a gradient method is required. 4 Interferences No interferences have been detected. Iron chelates with o,o-EDDHA, o,p-EDDHA, o,o-EDDHMA, EDTA, DTPA, CDTA, HEDTA, as well as the chelating agents do not interfere since they are separated from Fe3+
26、/EDDHSA 5 Reagents 5.1 General a) All reagents shall be of recognized analytical grade. b) All water used for the preparation of eluent, standards, and sample solutions should be water type 1 according to EN ISO 3696. c) When products with a declared purity of less than 99 % are used for the prepara
27、tion of standard solutions, a correction should be made in order to obtain the required concentration in the solution. 5.2 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 free of carbon dioxide. Dilute to the mark and homoge
28、nize. 5.3 Sodium hydroxide solution c(NaOH) = 0,1 mol/l CEN/TS 15451:2006 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:28:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 5 Dissolve 4 g of NaOH in pellet form in a 1 litre volumetric flask with water free of c
29、arbon dioxide. Dilute to the mark and homogenize. 5.4 Hydrochloric acid solution c(HCl) = 1,0 mol/l Dilute 88 ml of hydrochloric acid (35 % HCl) to 1 000 ml with water. 5.5 Hydrochloric acid solution c(HCl) = 0,1 mol/l Dilute 50 ml of hydrochloric acid (5.4) to 500 ml with water. 5.6 Iron (III) nitr
30、ate solution (Fe) = 1 050 mg/l Dissolve 0,7594 g of iron (III) nitrate nonahydrate Fe(NO3)39H2O in 100 ml of water. Transfer to a 100 ml- volumetric flask. Dilute to the mark with water and homogenize. Check (for example by AAS) that the Fe concentration of this solution is (1 050 30) mg/l. As the F
31、e(NO3)39H2O is deliquescent, for preparation of the Fe3+/EDDHSA solution (5.7) it shall be added in solution of a known concentration. 5.7 Fe3+/EDDHSA solution (Fe) = 100 mg/l Dissolve 0,233 0 g100/P, where P is the complexometric purity of the standard in percentage of the acid form H6EDDHSA obtain
32、ed by photometric titration with a Fe(III)standard in a pH stat system, of ethylene diamine di(2-hydroxy-5-sulfophenyl) acetic acid and its condensation products (EDDHSA) in 150 ml of water and 2,7 ml of NaOH (5.2). After complete dissolution, add 25 ml of the Fe solution (5.6) to the chelating agen
33、t solution stirring about 5 min. The solution is adjusted to pH 7,0 with NaOH solution (5.3). Let the solution stand overnight in darkness to allow excess Fe to precipitate as oxide. Filter quantitatively through a cellulose filter and make up to volume (250 ml) with water. 5.8 Eluent for the determ
34、ination Two solutions are used to make a linear gradient eluent: Solution A: Add 3,33 ml of TBAOH 40 % (mass fraction) Tetrabutylammonium hydroxide solution in water to 500 ml of water. Adjust pH to 6,0 with HCl (5.4 and 5.5). Add 350 ml of acetonitrile (HPLC grade) and make up to volume in a 1 litr
35、e-volumetric flask with water. Filter through 0,2 m membrane filter (6.3 b). Solution B: Add 3,33 ml of TBAOH 40 % (mass fraction) Tetrabutylammonium hydroxide solution in water to 150 ml of water. Adjust pH to 6,0 with HCl (5.4 and 5.5). Add 750 ml of acetonitrile (HPLC grade) and make up to volume
36、 in a 1 litre-volumetric flask with water. Filter through 0,2 m-membrane filter (6.3 b). NOTE 1 TBACl or TBABr may be used, providing that pH is adjusted to 6,0 with NaOH or HCl. NOTE 2 Tetrabutylammonium bisulfate should be avoided because peak retention times and shape may significantly change. CE
37、N/TS 15451:2006 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:28:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 6 6 Apparatus Usual laboratory equipment, glassware, and: 6.1 Magnetic stirrer Magnetic stirrer with magnets. 6.2 Chromatograph Chromatograph equi
38、pped with: a) gradient pump delivering the eluent at a flow rate of 1,5 ml/min (see Table 1); b) injection valve with a 20 l injection loop; c) C18 column; 150 mm3,9 mm ID; dp = 5 m1); d) use of a C18 guard column is recommended; e) UV/VIS-detector with a 480 nm-filter or diode array; f) integrator.
39、 Table 1 Gradient table Time min Flow rate ml/min A % B % Curve type 1,5 100 0 Linear 5 1,5 100 0 Linear 6 1,5 0 100 Linear 11 1,5 0 100 Linear 12 1,5 100 0 Linear 20 1,5 100 0 Linear 6.3 Membrane filters a) Micromembrane filters resistant to aqueous solutions, with porosity of 0,45 m; b) Micromembr
40、ane filters resistant to organic solutions, (e.g.: nylon micromembrane filters) with porosity of 0,2 m. 7 Sampling and sample preparation Sampling is not part of the method specified in this document. A recommended sampling method is given in prEN 1482-1. 1) SYMMETRYTM C18, from WATERS cat.n: WAT054
41、205, or equivalent are examples of suitable products available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by CEN of these products. CEN/TS 15451:2006 Licensed Copy: London South Bank University, London South Bank Unive
42、rsity, Sat Dec 30 06:28:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 7 Sample preparation shall be carried out in accordance with prEN 1482-2. NOTE For the size reduction of samples with a high amount of chelating agents, it is not recommended to use a high speed laboratory mill. It is more conveni
43、ent to grind the sample in a mortar to a particle size less than 1 mm. 8 Procedure 8.1 Preparation of the sample solution of iron chelates Weigh approximately 125 mg within 0,1 mg, into a 100 ml-beaker (for samples with more than 4 % of chelated iron weigh 80 mg and for samples with less than 2 % of
44、 chelated iron weigh 250 mg). Add 80 ml of water. Stir on a magnetic stirrer for 30 min. Dilute to the mark in a 100 ml-volumetric flask with water and homogenize. 8.2 Preparation of the calibration solutions Pipette a volume (V ml) (see Table 2) of the Fe3+/EDDHSA standard solution (5.7) in six 100
45、 ml-volumetric flasks respectively. Make up to volume with water and homogenize. Table 2 Preparation of the calibration curve of Fe3+/EDDHSA Solution V ml Concentration of Fe in the form of Fe3+/EDDHSA mg Fe/l 1 1 1,0 2 5 5,0 3 10 10,0 4 25 25,0 5 50 50,0 6 100 100 8.3 Chromatographic analysis Immed
46、iately before injection, all solutions should be filtered through a 0.45 m-membrane filter (6.3 a). Inject the standard solutions (8.2.) into the chromatographic system (6.2). Measure the retention times and the areas of the Fe3+/EDDHSA chromatographic peaks for all solutions. Two chromatographic pe
47、aks appear for Fe3+/EDDHSA, corresponding with the different forms of Fe3+/EDDHSA (see Annex A). Draw the calibration graph with the added values of the two chromatographic peaks of the standard solutions of Fe3+/EDDHSA versus the chelated iron concentration (mg Fe/l) in the standards. Inject the sa
48、mple solution (8.1). Identify the chelating agent by the retention time of the obtained peaks (see Annex A) and if diode array detector is used, confirm with its UV-visible spectrum (see Annex B). Measure the areas of the peaks for the sample solution corresponding with the iron chelated by EDDHSA a
49、s chelating agent. Determine the concentration of the iron chelated (mg Fe/l) using the calibration graph. NOTE Normally the two chromatographic peaks in Fe3+/EDDHSA appear overlapped. For integration use baseline correction as indicated in Annex A, Figure A.1. CEN/TS 15451:2006 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 30 06:28:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 8 9 Expression of the result 9.1 Fe in Fe-chelates I