DIN EN 16206-2012 Animal feeding stuffs - Determination of arsenic by hydride generation atomic absorption spectrometry (HGAAS) after microwave pressure digestion (digestion with 6.pdf

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1、May 2012 Translation by DIN-Sprachendienst.English price group 11No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 65

2、.120!$|=;“1892624www.din.deDDIN EN 16206Animal feeding stuffs Determination of arsenic by hydride generation atomic absorptionspectrometry (HGAAS) after microwave pressure digestion (digestionwith 65 % nitric acid and 30 % hydrogen peroxide)English translation of DIN EN 16206:2012-05Futtermittel Bes

3、timmung von Arsen mit Atomabsorptionsspektrometrie-Hydridtechnik (HD-AAS) nachMikrowellen-Druckaufschluss (Aufschluss mit 65 % Salpetersure und 30 %Wasserstoffperoxid)Englische bersetzung von DIN EN 16206:2012-05Aliments pour animaux Dosage de larsenic par spectromtrie dabsorption atomique par gnrat

4、ion dhydrures(SAAGH) aprs digestion sous pression par micro-ondes (Extraction lacide nitrique 65 % et au peroxyde dhydrogne 30 %)Traduction anglaise de DIN EN 16206:2012-05www.beuth.deDocument comprises 18 pagesIn case of doubt, the German-language original shall be considered authoritative.05.12 DI

5、N EN 16206:2012-05 2 A comma is used as the decimal marker. National foreword This standard has been prepared by Technical Committee CEN/TC 327 “Animal feeding stuffs Methods of sampling and analysis” (Secretariat: NEN, Netherlands) under a mandate. The responsible German body involved in its prepar

6、ation was the Normenausschuss Lebensmittel und landwirtschaftliche Produkte (Food and Agricultural Products Standards Committee), Working Committee NA 057-03-03 AA Futtermittel. The method described in this standard is based upon a method developed by the Verband Deutscher Landwirtschaftlicher Unter

7、suchungs- und Forschungsanstalten (VDLUFA) (Association of German Agricultural Experimental and Research Stations) and verified by interlaboratory tests. The DIN Standards corresponding to the International Standards referred to in this document are as follows, whereby EN ISO Standards are only list

8、ed below if these have not been published as DIN EN ISO Standards with the same number: EN ISO 3696 DIN ISO 3696 National Annex NA (informative) Bibliography DIN ISO 3696, Water for analytical laboratory use Specification and test methods EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16206 Fe

9、bruary 2012 ICS 65.120 English Version Animal feeding stuffs - Determination of arsenic by hydride generation atomic absorption spectrometry (HGAAS) after microwave pressure digestion (digestion with 65 % nitric acid and 30 % hydrogen peroxide) Aliments pour animaux - Dosage de larsenic par spectrom

10、trie dabsorption atomique par gnration dhydrures (SAAGH) aprs digestion sous pression par micro-ondes (Extraction lacide nitrique 65 % et au peroxyde dhydrogne 30 %) Futtermittel - Bestimmung von Arsen mit Atomabsorptionsspektrometrie-Hydridtechnik (HD-AAS) nach Mikrowellen-Druckaufschluss (Aufschlu

11、ss mit 65% Salpetersure und 30% Wasserstoffperoxid) This European Standard was approved by CEN on 30 December 2011. 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

12、 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 CEN member. This European Standard exists in three official versions (English, French, German). A version in any other languag

13、e 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 versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark,

14、Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMAL

15、ISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16206:2012: EEN 16206:2012 (E) 2 Contents Page Foreword 31 Scope 42 Normative referenc

16、es 43 Principle 44 Reagents .55 Apparatus and equipment 66 Procedure .76.1 General 76.2 Preparation of the test solution 76.3 Measurement of the test solution 87 Calculation 98 Precision 108.1 Introduction . 108.2 General . 108.3 Repeatability 108.4 Reproducibility 109 Test report . 11Annex A (infor

17、mative) Results of the inter-laboratory test 12Annex B (informative) Flowchart - Determination of arsenic by hydride generation atomic absorption spectrometry (HGAAS) after microwave pressure digestion (digestion with 65 % nitric acid and 30 % hydrogen peroxide) 13Annex C (informative) Alternative d

18、igestion procedure with the same digestion efficiency to ensure complete mineralization of all organic and inorganic arsenic species for HGAAS measurement: dry ashing with magnesium oxide and magnesium nitrate as ashing reagents . 15Bibliography . 16DIN EN 16206:2012-05 EN 16206:2012 (E) 3 Foreword

19、This document (EN 16206:2012) has been prepared by Technical Committee CEN/TC 327 “Animal feeding stuffs”, the secretariat of which is held by NEN. 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

20、August 2012, and conflicting national standards shall be withdrawn at the latest by August 2012. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such pate

21、nt rights. This 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 implement this European Standard

22、: Austria, Belgium, Bulgaria, Croatia, 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, Turkey and the Un

23、ited Kingdom. DIN EN 16206:2012-05 EN 16206:2012 (E) 4 1 Scope This European Standard specifies a method for the determination of total arsenic in animal feeding stuffs by hydride generation atomic absorption spectrometry (HGAAS) after microwave pressure digestion. The limit of quantification is 0,5

24、 g/l of the test solution. Using a test portion of 0,5 g, a volume of the test solution of 25 ml and an aliquot of 5 ml for pre-reduction the limit of quantification is 0,125 mg/kg in the feed material. NOTE For feed materials containing organic arsenic species from compounds of marine origin (i.e.

25、arsenobetaine and tetramethylarsine oxide) a higher digestion temperature of the microwave system up to 300 C may be necessary in order to enable the hydridisation of these arsenic compounds and in order to determine all different kinds of arsenic species in the corresponding feeding stuffs. Alterna

26、tively, the digestion procedure of Annex C can be used if the microwave system does not reach higher temperatures up to 300 C to ensure complete mineralization for HGAAS determination. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document an

27、d are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696) EN ISO 6

28、497, Animal feeding stuffs Sampling (ISO 6497) prEN ISO 6498, Animal feeding stuffs Guidelines for sample preparation (ISO/DIS 6498) 3 Principle Arsenic is determined in the test solution by hydride generation atomic absorption spectrometry (HGAAS) after microwave pressure digestion and a pre-reduct

29、ion step. The homogenised feeding stuff test sample is digested by nitric acid and hydrogen peroxide under pressure and high temperatures in a microwave-heated pressure digestion system. Arsenic ions of the test solution are reduced with a potassium iodide/ascorbic acid solution and hydrochloric aci

30、d to arsenic (III) and converted to arsenic hydride (AsH3) by sodium borohydride. Arsenic hydride is transferred by a gas stream into a heated measurement cell and decomposed. The absorption at the arsenic line at 193,7 nm corresponds to the amount of arsenic. Since arsenic (III) and arsenic (V) sho

31、w a different sensitivity with the hydride technique, it is necessary to reduce arsenic (V) to arsenic (III) in order to avoid incorrect measurements. Other digestion procedures with the same digestion efficiency are possible in order to completely mineralize all arsenic species like organic arsenic

32、 species from compounds of marine origin for HGAAS determination (see Annex C). NOTE 1 When using e.g. perchloric acid as alternative digestion procedure to ensure complete mineralisation of all organic and inorganic arsenic species for HGAAS determination you must use NaI/L-ascorbic acid because KI

33、 results in precipitation of potassium perchlorate. NOTE 2 Alternatively, inductively-coupled-plasma mass-spectrometry (ICP-MS) for measuring can be used where an incomplete mineralization is not of importance. WARNING The use of this standard can involve hazardous materials, operations and equipmen

34、t. This standard does not purport to address all the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. DIN EN 16206:2012-05 EN 162

35、06:2012 (E) 5 4 Reagents The concentration of the trace elements in the reagents and water used shall be low enough not to affect the results of the determination. A blank should be measured simultaneously with the test samples on each day of the analysis to control contamination and carry over with

36、 arsenic in the reagents and apparatus used. Use water conforming to grade 2 of EN ISO 3696. NOTE High purity is essential to avoid potential contamination. Therefore, only use reagents available with high purity or perform a digestion by a sub-boiling distillation for nitric acid (4.1). 4.1 Nitric

37、acid, not less than 65 % (mass fraction), of approximately (HNO3) = 1,4 g/ml. 4.2 Hydrogen peroxide, not less than 30 % (mass fraction), of approximately (H2O2) 1,1 g/ml. 4.3 Hydrochloric acid, 30 % (mass fraction), of approximately (HCl) 1,15 g/ml. 4.4 Diluted hydrochloric acid, e.g. about 3 % (mas

38、s fraction), used as carrier solution in the flow injection procedure and for dilution of the arsenic stock solution to the 1 mg/l standard solution and furthermore to the calibration solutions. EXAMPLE Dilute approximately 90 ml of hydrochloric acid (4.3) to 1 l with water. 4.5 Sodium borohydride s

39、olution, e.g. c = 2 g/l. Dissolve 2 g of sodium hydroxide pellets in water, add 2 g of sodium borohydride and dilute to 1 000 ml with water into 1 000 ml flask (5.3). Prepare a fresh solution daily and, when necessary, filter before use. When the analysis procedure takes longer, it is recommended to

40、 cool the sodium borohydride solution, i.e. with ice around the flask, during its use in the HGAAS measurement. NOTE 1 The concentration by mass of the sodium borohydride solution may vary with the system and the instructions of the relevant manufacturer shall therefore be observed. NOTE 2 Sodium bo

41、rohydride, stable aq. solution, 4,4 mol/l in 14 mol/l NaOH is also commercially available. WARNING It is essential to observe the safety instructions for working with sodium borohydride. Sodium borohydride forms hydrogen with acids and this can result in an explosive air/hydrogen mixture. A permanen

42、t extraction system shall be provided at the point where measurements are carried out. 4.6 Potassium iodide/ascorbic acid solution. Dissolve 2,5 g of potassium iodide and 2,5 g of L-ascorbic acid in water and dilute to 100 ml. Prepare a fresh solution on the day of the analysis. NOTE The concentrati

43、ons of the potassium iodide and ascorbic acid may vary slightly with the system and the instructions of the relevant manufacturer shall therefore be observed. 4.7 Arsenic stock solution, c (As) = 1 000 mg/l. Stock solutions are commercially available. It is advisable to use certified stock solutions

44、. Otherwise dissolve 1,320 g of diarsenic trioxide (As2O3) in 25 ml of potassium hydroxide solution (c = 20 g/100 ml), neutralize with 20 % (mass fraction) sulfuric acid with phenolphthalein as indicator and dilute to 1 000 ml with 1 % (mass fraction) sulfuric acid. 4.8 Arsenic standard solution, c

45、(As) = 1 mg/l. Pipette, for example, 100 l of the stock solution (4.7) into a 100 ml flask (5.3) and fill up with hydrochloric acid (4.4) to reach a concentration of 1 mg/l. DIN EN 16206:2012-05 EN 16206:2012 (E) 6 NOTE The standard solution is stable for at least three months. 4.9 Arsenic calibrati

46、on solutions. For the preparation of five calibration solutions the following procedure is recommended: Dilute 0 ml, 1,25 ml, 2,5 ml, 7,5 ml and 12,5 ml of the arsenic standard solution (4.8) with hydrochloric acid (4.4) into 50 ml flasks (5.3) and mix thoroughly. Then pipette 1 ml of each solution

47、into 25 ml flasks (5.3), add 2,5 ml potassium iodide/ascorbic acid solution (4.6) and 2,5 ml of hydrochloric acid (4.3), mix thoroughly, and let the solutions stand at room temperature for 60 min. Finally make up to the mark with hydrochloric acid (4.4) and wait again 60 min at room temperature befo

48、re the calibration solutions are measured (see Table 2). The concentrations of the calibration solutions are: 0 g/l, 1 g/l, 2 g/l, 6 g/l and 10 g/l (see Table 1). Table 1 Calibration solution concentrations (4.9) after pre-reduction Arsenic (As) Concentration of calibration solution (4.9) after pipetting 1 ml from the 50 ml flasks (5.3) into 25 ml flasks (5.3) for pre-reduction g/l Aliquot of arsenic standard solut