DIN EN 15765-2010 Foodstuffs - Determination of trace elements - Determination of tin by inductively coupled plasma mass spectrometry (ICP-MS) after pressure digestion German versi.pdf

1、April 2010 Translation by DIN-Sprachendienst.English price group 9No 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 6

2、7.050!$aZq“1625578www.din.deDDIN EN 15765Foodstuffs Determination of trace elements Determination of tin by inductively coupled plasma mass spectrometry(ICP-MS) after pressure digestionEnglish translation of DIN EN 15765:2010-04Lebensmittel Bestimmung von Elementspuren Bestimmung von Zinn mit Massen

3、spektrometrie mit induktiv gekoppeltem Plasma(ICP-MS) nach DruckaufschlussEnglische bersetzung von DIN EN 15765:2010-04Produits alimentaires Dosage des lments traces Dosage de ltain par spectromtrie de masse plasma induit par haute frquence(ICP-MS) aprs digestion sous pressionTraduction anglaise de

4、DIN EN 15765:2010-04www.beuth.deIn case of doubt, the German-language original shall be considered authoritative.Document comprises 13 pages04.10 DIN EN 15765:2010-04 2 A comma is used as the decimal marker. National foreword This standard has been prepared by Technical Committee CEN/TC 275 “Food an

5、alysis Horizontal methods” (Secretariat: DIN, Germany). The responsible German body involved in its preparation was the Normenausschuss Lebensmittel und landwirtschaftliche Produkte (Food and Agricultural Products Standards Committee), Working Committee NA 057-01-09 AA Elemente und ihre Verbindungen

6、. The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 5725-1 DIN ISO 5725-1 ISO 5725-2 DIN ISO 5725-2 National Annex NA (informative) Bibliography DIN ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results Part 1:

7、General principles and definitions DIN ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 15765 December

8、 2009 ICS 67.050 English Version Foodstuffs - Determination of trace elements - Determination of tin by inductively coupled plasma mass spectrometry (ICP-MS) after pressure digestion Produits alimentaires - Dosage des lments traces - Dosage de ltain par spectromtrie de masse plasma induit par haute

9、frquence (ICP-MS) aprs digestion sous pression Lebensmittel - Bestimmung von Elementspuren - Bestimmung von Zinn mit Massenspektrometrie mit induktiv gekoppeltem Plasma (ICP-MS) nach Druckaufschluss This European Standard was approved by CEN on 7 November 2009. CEN members are bound to comply with t

10、he 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 CEN Management Centr

11、e 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 CEN Management Centre has the same status as the official

12、 versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Sloven

13、ia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN nat

14、ional Members. Ref. No. EN 15765:2009: EEN 15765:2009 (E) 2 Contents Page Foreword 31 Scope 42 Normative references 43 Principle 44 Reagents .45 Apparatus and equipment 56 Procedure .67 Evaluations .78 Precision .79 Test report 8Annex A (informative) Results of the inter-laboratory test .9Bibliograp

15、hy . 11DIN EN 15765:2010-04 EN 15765:2009 (E) 3 Foreword This document (EN 15765:2009) has been prepared by Technical Committee CEN/TC 275 “Food analysis - Horizontal methods”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by

16、 publication of an identical text or by endorsement, at the latest by June 2010, and conflicting national standards shall be withdrawn at the latest by June 2010. 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

17、shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark,

18、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. DIN EN 15765:2010-04 EN 15765:2009 (E) 4 1 Scope This European Sta

19、ndard specifies a method for the determination of tin in foodstuffs by inductively coupled plasma mass spectrometry (ICP-MS) after pressurized digestion. The collaborative study included carrot puree, tomato puree, pineapple, mixed fruit, white wine, peach powder, tomato powder, beans powder, powder

20、ed fruit yoghurt and fish powder foodstuffs having a mass fraction of tin ranging from 2,5 mg/kg to 259 mg/kg. 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 reference

21、s, the latest edition of the referenced document (including any amendments) applies. EN 13805, Foodstuffs Determination of trace elements Pressure digestion 3 Principle The sample is mineralized through pressurized digestion with nitric acid and hydrochloric acid in accordance with EN 13805. The dig

22、estion solution obtained thereby is diluted and then atomised and ionised in an inductively coupled argon plasma. After extraction from the plasma by a system of sampler and skimmer cones the positive (charged) tin ions are separated according to their mass charge ratio in a mass spectrometer and qu

23、antified in a detector system. 4 Reagents 4.1 General The concentration of tin in the reagents and water used shall be low enough not to affect the results of the determination. Solution shall be understood as an aqueous solution unless otherwise specified. 4.2 Nitric acid, mass fraction w(HNO3) 65

24、%, mass concentration (HNO3) 1,4 g/ml. 4.3 Hydrochloric acid, w(HCl) 30 %, density (HCl) 1,15 g/ml. 4.4 Stock solutions 4.4.1 Tin stock solution, mass concentration (Sn) = 1 000 mg/l. 4.4.2 Rhodium stock solution (internal standard), mass concentration (Rh) = 1 000 mg/l. 4.5 Standard solutions 4.5.1

25、 Tin standard solution 1, mass concentration (Sn) = 50 mg/l Fill a 50 ml volumetric flask with 10 ml to 20 ml of water, add 2,5 ml of hydrochloric acid (4.3) and mix. Cool to ambient temperature, and add by means of a pipette exactly 2,5 ml of tin stock solution (4.4.1) and dilute to volume with wat

26、er. This solution is stable for at least one week. DIN EN 15765:2010-04 EN 15765:2009 (E) 5 4.5.2 Tin standard solution 2, mass concentration (Sn) = 1,0 mg/l Fill a 50 ml volumetric flask with 10 ml to 20 ml of water, add 2,5 ml of hydrochloric acid (4.3) and mix. Cool to ambient temperature, and ad

27、d by means of a pipette exactly 1,0 ml of tin standard solution 1 (4.5.1) and dilute to volume with water. This solution is stable for one week. 4.5.3 Rhodium standard solution, mass concentration (Rh) = 10 mg/l Fill a 50 ml volumetric flask with 10 ml to 20 ml of water, add 2,5 ml of hydrochloric a

28、cid (4.3) and mix. Cool to ambient temperature, and add by means of a pipette exactly 0,5 ml of rhodium stock solution (4.4.2) and dilute to volume with water. This solution is stable for at least four weeks. 4.6 Calibration solutions The following concentrations of the calibration solutions are exa

29、mples and may be changed according to the sensitivity of measuring instrument and the concentration range to be investigated. Care shall be taken that calibration is carried out within the linear range of the detector system while paying attention to the varying frequency of isotopes. The quantity o

30、f internal standard added should be sufficient enough to obtain a stable and reproducible intensity. For calibration at least three calibration solutions of different concentration shall be used. The acid concentration should correspond to the one in the measuring solution. The preparation of the fo

31、llowing solutions is given as an example: Calibration solutions with mass concentrations of 5 g/l, 10 g/l, 20 g/l and 40 g/l. The calibration solutions are prepared from the tin standard solution 2 (4.5.2) according to following procedure: Fill four 50 ml volumetric flasks with 10 ml to 20 ml of wat

32、er, add 0,5 ml of nitric acid (4.2) and 0,1 ml of hydro-chloric acid (4.3) and mix. Cool to ambient temperature, and pipette exactly the same amount of internal standard, e.g. 0,5 ml of rhodium standard solution (4.5.3), into each of the measuring flasks. Then, for the calibration solutions of mass

33、concentrations of 5 g/l, 10 g/l, 20 g/l and 40 g/l, pipette exactly 0,25 ml, 0,50 ml, 1,0 ml and 2,0 ml of the standard solution 2 (4.5.2), respectively, into the four separate 50 ml volumetric flasks and make up to volume with water. These solutions shall be freshly prepared on each day of measurem

34、ent. The calibration solutions described here shall be understood as examples. The concentrations prepared shall be in the linear range of the ICP-MS detector system. Furthermore, the acid concentration of the calibration solutions shall be matched to the amounts of acid being present in the diluted

35、 digestion solution. 4.7 Blank solution (blank solution) The blank solution contains water, nitric acid and hydrochloric acid in amounts that correspond to the concentrations in the measurement solution, for example 0,5 ml of nitric acid (4.2) and 0,1 ml of hydrochloric acid (4.3) in 50 ml as well a

36、s the same amount of internal standard (0,5 ml rhodium standard solution (4.5.3) as used for the calibration solutions in 50 ml. 5 Apparatus and equipment 5.1 General All apparatus and equipment that come into direct contact with the sample and solutions shall be pre-cleaned appropriately. DIN EN 15

37、765:2010-04 EN 15765:2009 (E) 6 5.2 ICP-MS instrument with inductively coupled argon plasma as ionisation unit, sample feeding and nebulising system as well as an instrument controlling unit and an evaluation unit. 6 Procedure 6.1 Digestion of the sample Mineralize the sample by pressurized digestio

38、n in accordance with EN 13805. For the quantification of tin, add 0,5 ml to 1 ml of hydrochloric acid (4.3) to the digestion vessel, which contains nitric acid (4.2) used for digestion, at an amount that corresponds to the amount of nitric acid. Do not add the hydrochloric acid until the spontaneous

39、 reaction with nitric acid has subsided. After addition of the hydrochloric acid close the digestion vessel immediately in order to avoid loss of active chlorine. Start pressurized digestion shortly thereafter. The digestion requirements are based on the specifications of the instrument manufacturer

40、, the reactivity of the sample, the maximum pressure stability of the digestion vessel and the attainable temperature. EXAMPLE 1 Precisely weigh 0,4 g to 0,5 g of dry sample (residual moisture of less than 20 %) into a 100 ml digestion vessel and add 5 ml of nitric acid (4.2). Carefully shake the di

41、gestion vessel to prevent clots from forming in the sample. After the spontaneous reaction has subsided, add 1 ml of hydrochloric acid (4.3) and close the digestion vessel as quickly as possible. For samples with a higher degree of moisture content, the weighed quantities can be increased. The diges

42、tion solution that results from the pressurized digestion according to EN 13805 is made up to a defined volume, e.g. 20 ml, by water. This solution is diluted, using water, by a factor of 10 or higher for the subsequent determination of tin. It is important that the amount of internal standard is ex

43、actly the same, both in the measurement solutions and in the calibrations solutions. EXAMPLE 2 For preparation of the measurement solution directly in the vessel used for measurement, pipette exactly 1,0 ml digestion solution and 0,5 ml rhodium standard solution (4.5.3) into the measurement vessel a

44、nd make up with water to 10 ml. This solution should be measured on the day of preparation. 6.2 Inductively coupled plasma mass spectrometry 6.2.1 ICP-MS operating conditions Set the instrument according to the manufacturers specifications and ignite the plasma. Following sufficient warming up and s

45、tabilization of the instrument, optimise the settings. 6.2.2 Determination by ICP-MS Once the instrument is optimised start the measurements. For evaluation tin isotopes of the masses 117 and 118 shall be used. The internal standard rhodium is analysed for the mass 103. Correction with internal stan

46、dard is implemented by the method settings of the instrument software. Measure the blank solution (4.7) and calibration solutions (4.6) and use the counting rate (counts/s) and concentrations to generate a calibration curve. Determine the linear range of the calibration function. The measurement sol

47、ution is aspirated and measured. Use the calibration curve to convert the determined counting rate into concentration units. 6.3 Quality control For quality control, analyse a reference material with reliably known content of tin in parallel to each series of measurements. Include all procedural ste

48、ps starting at the digestion. This also applies to each series of digestions including all procedural steps to prepare and measure blank solutions. DIN EN 15765:2010-04 EN 15765:2009 (E) 7 7 Evaluations 7.1 Calculation of the tin content in foodstuffs Calculate the tin content, w, in milligrams per

49、kilogram of sample or , in milligrams per litre of sample according to Equation (1): w or = 000100010001EFVa(1) where a is the mass concentration of tin of the measurement solution, in micrograms per litre (g/l); V is the volume of the digestion solution diluted to volume, in millilitres (ml); E is the initial sample mass, in grams (g), or the initial sample volume, in millilitres (ml); F is the dilution factor ( 10). 7.2 Limit of quantification The ICP-MS instrument sho