SIST EN 15111:2007

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Foodstuffs - Determination of trace elements - Determination of iodine by ICP-MS (inductively coupled plasma mass spectrometry)Produits alimentaires - Dosage des éléments traces - Dosage de l'iode par spectrométrie d'émission avec plasma induit par haute fréquence et spectrometre de masse (ICP-SM)Lebensmittel - Bestimmung von Elementspuren - Bestimmung von Iod mit der ICP-MS (Massenspektrometrie mit induktiv gekoppeltem Plasma)Ta slovenski standard je istoveten z:EN 15111:2007SIST EN 15111:2007en;fr;de67.050Splošne preskusne in analizne metode za živilske proizvodeGeneral methods of tests and analysis for food productsICS:SIST-TS CEN/TS 15111:20051DGRPHãþDSLOVENSKI
STANDARDSIST EN 15111:200701-julij-2007







EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 15111March 2007ICS 67.050Supersedes CEN/TS 15111:2005
English VersionFoodstuffs - Determination of trace elements - Determination ofiodine by ICP-MS (inductively coupled plasma massspectrometry)Produits alimentaires - Dosage des éléments traces -Dosage de l'iode par spectrométrie d'émission avec plasmainduit par haute fréquence et spectromètre de masse (ICP-SM)Lebensmittel - Bestimmung von Elementspuren -Bestimmung von Iod mit der ICP-MS(Massenspektrometrie mit induktiv gekoppeltem Plasma)This European Standard was approved by CEN on 21 January 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN 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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial 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, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2007 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15111:2007: E



EN 15111:2007 (E) 2 Contents Page Foreword.3 1 Scope.4 2 Normative references.4 3 Principle.4 4 Reagents.4 5 Apparatus and equipment.6 6 Sampling.7 7 Procedure.7 8 Calculation.9 9 Limit of quantification.9 10 Precision.9 11 Test report.10 Annex A (normative)
Results of the inter-laboratory test.11 Bibliography.12



EN 15111:2007 (E) 3 Foreword This document (EN 15111:2007) 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 publication of an identical text or by endorsement, at the latest by September 2007, and conflicting national standards shall be withdrawn at the latest by September 2007. This document supersedes CEN/TS 15111:2005. 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, 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.



EN 15111:2007 (E) 4 1 Scope This European Standard specifies an extraction method for the determination of iodine compounds in foodstuffs by inductively coupled plasma mass spectrometry (ICP-MS). 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. EN 13804, Foodstuffs — Determination of trace elements — Performance criteria, general considerations and sample preparation 3 Principle Iodine compounds are extracted with a strong alkaline reagent at elevated temperature. After removing
un-dissolved components, the nebulized solution is atomized and ionized in an inductively coupled argon plasma. The ions are extracted from the plasma by a system of sampler and skimmer cones, separated in a mass spectrometer on the basis of their mass/charge ratio and determined using a pulse counting detector system. WARNING — The use of this European Standard may involve hazardous materials, operations and equipment. This European Standard does not purport to address all the safety problems associated with its use. It is the responsibility of the user of this European Standard to establish appropriate safety and health practices and determine the applicability or regulatory limitations prior to use. 4 Reagents 4.1 General The concentration of iodine in the reagents and water used shall be low enough not to affect the results of the determination, e.g. different qualities of TMAH are available. It is important to check, that the iodine content is low enough for the analysis. 4.2 Tetramethylammonium hydroxide (TMAH = (CH3)4N+OH-) solution,
mass concentration ρ = 250 g/l, (mass fraction w = 25 %), suitable for trace analysis with an iodine content of less than 1 µg/l. 4.3 Diluted tetramethylammonium hydroxide (TMAH) solution Dilute TMAH solution for preparing the zero member compensation and calibration solutions, with a concentration to suit that of the sample solution (see 7.3). Prepare a 0,5 % TMAH solution by diluting 1,0 ml of TMAH solution (4.2) to 50 ml with water. 4.4 Stock solutions 4.4.1 General Commercial stock solutions may be used as an alternative to the solutions described below.



EN 15111:2007 (E) 5 4.4.2 Iodine stock solution (KIO3), ρ = 1 000 mg/l, purity: mass fraction w > 99,5 %. Dissolve 1,686 4 g of potassium iodate in water and dilute to 1 l with water. 4.4.3 Tellurium stock solution, ρ = 1 000 mg/l. Dissolve 1,250 8 g of tellurium dioxide (TeO2) in 4 mol/l hydrochloric acid and dilute to 1 l with water. 4.5 Standard solutions 4.5.1 Iodine standard solution, ρ = 10 mg/l. Pipette 1 ml of the iodine stock solution (4.4.2) into a 100 ml volumetric flask and dilute to the mark with water. This solution is stable for about four weeks and is used to prepare the calibration solutions in 4.6. 4.5.2 Tellurium standard solution (internal standard) Tellurium has proved satisfactory as an internal standard for determining iodine since it has a mass in a comparable range and an ionization energy similar to that of iodine. The original tellurium content in the sample to be analysed shall be negligible. If that is not the case, another suitable internal standard shall be used. Prepare e.g. a 10 mg/l standard tellurium solution by pipetting 1 ml ml of the tellurium stock solution (4.4.3) into a 100 ml volumetric flask and dilute to the mark with water. This solution is stable for about four weeks. 4.6 Iodine calibration solutions 4.6.1 General The concentrations of the calibration solutions specified below are given as example and may be modified to suit the sensitivity of the apparatus and the concentration range to be covered. The linear range of the detector system shall not be exceeded. The internal standard added to the calibration solutions shall have a concentration high enough to reach a stable detector count rate. The calibration, zero member compensation and sample solutions shall contain exactly the same amount of internal standard. The TMAH concentrations in the reference solutions shall be approximately equal to that of the sample solution. 4.6.2 Calibration solution 1 ρ = 5 µg/l. Fill a 50 ml volumetric flask with about 30 ml of diluted TMAH solution (4.3). Pipette 2,5 ml of tellurium standard solution (4.5.2) into the flask and mix. Add 25 µl of iodine standard solution (4.5.1) to this mixture and fill to the mark with diluted TMAH solution (4.3). 4.6.3 Calibration solution 2 ρ = 20 µg/l. Fill a 50 ml volumetric flask with about 30 ml of diluted TMAH solution (4.3). Pipette 2,5 ml of tellurium standard solution (4.5.2) into the flask and mix. Add 100 µl of iodine standard solution (4.5.1) to this mixture and fill to the mark with diluted TMAH solution (4.3).



EN 15111:2007 (E) 6 4.6.4 Calibration solution 3 ρ = 50 µg/l. Fill a 50 ml volumetric flask with about 30 ml of diluted TMAH solution (4.3). Pipette 2,5 ml of tellurium standard solution (4.5.2) into the flask and mix. Add 250 µl of iodine standard solution (4.5.1) to this mixture and fill to the mark with diluted TMAH solution (4.3). The calibration solutions shall be prepared freshly every day. 4.7 Zero member compensation solution, containing water and the same amount of TMAH and internal standard as the sample solution. E.g. fill a 50 ml volumetric flask with about 30 ml of diluted TMAH solution (4.3). Pipette 2,5 ml of tellurium standard solution (4.5.2) into the flask, mix and fill to the mark with diluted TMAH solution (4.3). 5 Apparatus and equipment 5.1 General To minimize the blank, all apparatus that comes into direct contact with the sample and the solutions used shall be carefully pre-treated with a diluted TMAH solution (e.g. as in 4.3) and then rinsed with water. 5.2 Vessels, gastight sealable, glass or quartz, of capacity 30 ml to 100 ml, e.g. screw-thread Erlenmeyer flask, 100 ml with plastic screw caps and PTFE-protected seal. As an alternative, plastic vessels that can be gastightly sealed and are able to withstand a temperature of not less than 110 °C (e.g. made of polypropylene, high-density polyethylene or polyfluorine (such as PFA)) may be used. NOTE If plastic vessels are repeatedly used, there is a risk of higher blanks, in particular if samples having fairly high iodine contents are extracted in them. 5.3 Plastic syringes, of capacity 5 ml to 25 ml, preferably with a bayonet-like connection (e.g. Luer lock). 5.4 Ultracentrifuge, as an alternative to 5.3, having an acceleration of not less than 10 000 g and equipped with suitable rotors or adapters for accommodating vessels that can be sealed gastight. 5.5 Membrane filters, as dispensable syringe attachment. 5.5.1 Membrane filter, having a pore size of 5 µm, with a connection fitting the syringes in 5.3, not necessary if ultracentrifuge (5.4) is used 5.5.2 Membrane filter, having a pore size of 0,45 µm or less,
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