SIST EN 14084:2003
(Main)Foodstuffs - Determination of trace elements - Determination of lead, cadmium, zinc, copper and iron by atomic absorption spectrometry (AAS) after microwave digestion
Foodstuffs - Determination of trace elements - Determination of lead, cadmium, zinc, copper and iron by atomic absorption spectrometry (AAS) after microwave digestion
This European standard specifies a method for the determination of Pb, Cd, Zn, Cu and Fe in foodstuffs by atomic absorption spectrometry (AAS) after microwave digestion. This method describes determination in various types of foods, with the exception of oils, fats and other extremely fatty products. The method has been successfully tested in an interlaboratory trial in which 16 laboratories participated. Food types covered by the method include composite diets, cereals, fish, beef, milk and fungi.
Lebensmittel - Bestimmung von Elementspuren - Bestimmung von Blei, Cadmium, Zink, Kupfer und Eisen mit Atomabsorptionsspektrometrie (AAS) nach Mikrowellenaufschluss
Produits alimentaires - Dosage des éléments traces - Dosage du plomb, du cadmium, du zinc, du cuivre et du fer par spectrométrie d'absorption atomique (AAS) apres digestion par micro-ondes
La présente Norme européenne spécifie une méthode de détermination du plomb, du cadmium, du zinc, du cuivre et du fer dans les produits alimentaires par spectrométrie d'absorption atomique (AAS) apres digestion par micro-ondes.
Cette méthode s'applique a divers types de produits alimentaires. Elle ne s'applique pas aux huiles, graisses ni autres produits extremement gras.
Cette méthode a satisfait a un essai interlaboratoire auquel ont participé 16 laboratoires [1]. Les produits alimentaires concernés par cette méthode comprennent les repas composés, les céréales, le poisson, la viande de b?uf, le lait et les champignons.
Les produits alimentaires spécifiques faisant l'objet de Normes européennes sont exclus du domaine d'application de la présente Norme européenne horizontale. Il incombe a l'analyste de
Živila - Določevanje elementov v sledovih - Določevanje svinca, kadmija, cinka, bakra in železa z atomsko absorpcijsko spektrometrijo (AAS) po mikrovalovnem razklopu
General Information
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.NURYDORYQHPUD]NORSXLebensmittel - Bestimmung von Elementspuren - Bestimmung von Blei, Cadmium, Zink, Kupfer und Eisen mit Atomabsorptionsspektrometrie (AAS) nach MikrowellenaufschlussProduits alimentaires - Dosage des éléments traces - Dosage du plomb, du cadmium, du zinc, du cuivre et du fer par spectrométrie d'absorption atomique (AAS) apres digestion par micro-ondesFoodstuffs - Determination of trace elements - Determination of lead, cadmium, zinc, copper and iron by atomic absorption spectrometry (AAS) after microwave digestion67.050Splošne preskusne in analizne metode za živilske proizvodeGeneral methods of tests and analysis for food productsICS:Ta slovenski standard je istoveten z:EN 14084:2003SIST EN 14084:2003en01-junij-2003SIST EN 14084:2003SLOVENSKI
STANDARD
SIST EN 14084:2003
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 14084April 2003ICS 67.050English versionFoodstuffs - Determination of trace elements - Determination oflead, cadmium, zinc, copper and iron by atomic absorptionspectrometry (AAS) after microwave digestionProduits alimentaires - Dosage des éléments traces -Dosage du plomb, du cadmium, du zinc, du cuivre et du ferpar spectrométrie d'absorption atomique (AAS) aprèsdigestion par micro-ondesLebensmittel - Bestimmung von Elementspuren -Bestimmung von Blei, Cadmium, Zink, Kupfer und Eisenmit Atomabsorptionsspektrometrie (AAS) nachMikrowellenaufschlussThis European Standard was approved by CEN on 18 December 2002.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 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 Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and UnitedKingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2003 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14084:2003 ESIST EN 14084:2003
EN 14084:2003 (E)2ContentspageForeword.31Scope.32Normative references.33Principle.34Reagents.45Apparatus and equipment.56Procedure.57Calculation.88Precision.89Test report.9Annex A (informative)
Results of the interlaboratory test.10Bibliography.16SIST EN 14084:2003
EN 14084:2003 (E)3ForewordThis document (EN 14084:2003) 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 orby endorsement, at the latest by October 2003, and conflicting national standards shall be withdrawn at the latestby October 2003.Annex A is informative.According to the CEN/CENELEC Internal Regulations, the national standards organizations of the followingcountries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,Slovakia, Spain, Sweden, Switzerland and the United Kingdom.1 ScopeThis European Standard specifies a method for the determination of lead, cadmium, zinc, copper and iron infoodstuffs by atomic absorption spectrometry (AAS) after microwave digestion.The method is applicable to determination in various types of foodstuffs. The method is not applicable to oils, fatsand other extremely fatty products.The method has been successfully tested in an interlaboratory trial in which 16 laboratories participated [1].Foodstuffs covered by the validation of the method include composite diets, cereals, fish, beef, milk and fungi.Specific foodstuffs for which European Standards exist are excluded from the scope of this horizontal EuropeanStandard. It is the task of the analyst to review if vertical standards exist.2 Normative referencesThis European Standard incorporates by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text, and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision. For undated references the latest edition of thepublications referred to applies (including amendments).EN 13804, Foodstuffs - Determination of trace elements - Performance criteria, general considerations and samplepreparation.3 PrincipleThe samples are digested in closed vessels in a microwave oven in a mixture of nitric acid and hydrogen peroxide.The resulting solution is diluted with water, and the metal contents are determined by flame or graphite furnaceatomic absorption spectrometry-procedures.WARNING — The use of this standard can involve hazardous materials, operations and equipment. Thisstandard does not purport to address all the safety problems associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine theapplicability of regulatory limitations prior to use.SIST EN 14084:2003
EN 14084:2003 (E)44 Reagents4.1 GeneralThe concentration of the trace elements in the reagents and water used shall be low enough not to affect theresults of the determination.4.2 Nitric acid, not less than 65 %, (mass fraction), having a density of approximately r (HNO3) = 1,4 g/ml.4.2.1 Nitric acid, c » 0,1 mol/l:Dilute 7 ml concentrated nitric acid (4.2) with water to 1 000 ml.4.2.2 Nitric acid, c » 3 mol/l:Dilute 200 ml of concentrated nitric acid (4.2) with water to 1 000 ml.4.3 Hydrogen peroxide, 30 % (mass fraction).4.4 Standard solutionsNOTEThe standard solutions for Pb, Cd, Zn, Cu and Fe can be prepared from metals or metal salts. Standard solutionscan also be commercially available. It is advisable to use certified standard solutions. The following preparation of standardsolutions are given as an example.4.4.1 Lead standard solution, 1 000 mg/l:Dissolve 1,000 g Pb in 7 ml nitric acid (4.2) in a 1 000 ml volumetric flask. Dilute to volume with water.4.4.2 Cadmium standard solution, 1 000 mg/l:Dissolve 1,000 g Cd in 20 ml of a mixture of 10 ml water and 10 ml nitric acid (4.2) in a 1 000 ml volumetric flask.Dilute to volume with water.4.4.3 Zinc standard solution, 1 000 mg/l:Dissolve 1,000 g Zn in 14 ml of water and 7 ml nitric acid (4.2) in a 1 000 ml volumetric flask. Dilute to volume withwater.4.4.4 Copper standard solution, 1 000 mg/l:Dissolve 1,000 g Cu in 7 ml nitric acid (4.2) in a 1 000 ml volumetric flask. Dilute to volume with water.4.4.5 Iron standard solution, 1 000 mg/l:Dissolve 1,000 g Fe in 14 ml of water and 7 ml nitric acid (4.2) in a 1 000 ml volumetric flask. Dilute to volume withwater.4.5 Calibration solutionsDilute standard solutions 4.4.1 to 4.4.5 with c » 0,1 mol/l nitric acid (4.2.1) to a range of standards that covers thelinear range of the element to be determined.SIST EN 14084:2003
EN 14084:2003 (E)55 Apparatus and equipment5.1 GeneralAll glassware and plastic ware should be carefully cleaned and rinsed according to the procedure in EN 13804.5.2 Atomic absorption spectrometer, with background correction, supplied with a graphitefurnace/autosampler, burners for flame analysis and an appropriate gas supply.5.3 Element specific lamps, e.g. hollow cathode lamps, for all elements analysed.5.4 Graphite tubes, pyrolytically coated and with platforms for Pb and Cd.5.5 Microwave oven, designed for laboratory use (check for delivered power according to the procedure inEN 13804) and digestion vessels with a capacity of typically 100 ml and withstanding a pressure of at least1,4 MPa.5.6 Plastic bottles, with leak-proof closures, 100 ml.6 Procedure6.1 Pre-treatmentHomogenise the sample in accordance with the recommendations in EN 13804. If necessary, dry the sample in away that does not affect the element content, e.g. by freeze-drying.6.2 Pressure digestionWeigh an amount of sample equivalent to 0,2 g to 0,5 g dry matter into the digestion vessel (5.5) or asrecommended by the manufacturer of the microwave digestion oven used. The maximum test portion from asample having a water content of e.g. 50 % is thus 1 g (= 0,5 g dry matter); for a material containing 95 % water thetest portion may be 2 g (< 0,5 g dry matter). Include one reagent blank in every batch.Add to the digestion vessel typically 5 ml nitric acid (4.2) and 2 ml hydrogen peroxide (4.3) or as recommended bythe manufacturer of the microwave oven used. Seal the vessel and place it in its holder in the microwave oven andclose the door. Set the oven programme (power against time) as recommended by the manufacturer for theweighed type of sample.Typically an oven programme includes a stage at low power for a few minutes followed by one or more stages athigher power settings. A gradual increase between the selected stages is recommended in order to prevent suddenpressure peaks to occur inside the pressure vessels. An example of a programme has been shown in Table 1.SIST EN 14084:2003
EN 14084:2003 (E)6Table 1 — Pressure digestion programme(The parameters are given as an example applicable to a CEM MDS 2000 oven1)StepPower, WTime, min12503:0026305:00350022:004015:00The programme used should be valid on the condition that the full number of pressure vessels is treatedsimultaneously. If fewer vessels are digested, the remaining vessels may be treated as blanks. If the oven usedincludes pressure control in only one pressure vessel, that vessel with the expected highest pressure should bemonitored. This is generally the vessel with the highest sample intake calculated as the dry matter.When digesting unknown samples, observe caution since a too large amount of sample may rupture the safetymembrane of the digestion vessel. In particular, samples high in carbon (especially sugar, fat and/or ethanol) maycause sudden pressure peaks during the ashing process. In all cases, the sample intake should be in strictcompliance with the manufacturers recommendations.6.3 DilutionRemove the digestion vessels from the microwave oven and allow to cool thoroughly before attempting to openthem. Open the vessel and rinse down the lid and the walls with water into the container. Make up to a definitevolume, at least 25 ml, with water into a plastic bottle (5.6). Treat the blank in the same way.6.4 AAS6.4.1 GeneralThe method to be used – flame or graphite furnace technique – is determined by the concentration of the metal tobe analysed. Pb and Cd in foodstuffs generally require graphite furnace-AAS. Zn, Cu and Fe can usually beanalysed by flame AAS. Examples of wavelength, gas mixture/temperature programmes and other instrumentalparameters appropriate for each metal are found in manuals provided with the instrument. Background correctionshould always be used, unless proven to be unnecessary.It is important that the measurements are made in the linear range when the method of standard addition is used. Astandard addition curve should consist of at least three points of which at least two are standard additions. Theconcentration of the highest standard should be 3 to 5 times the concentration in the sample solution. The concen-t
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