SIST EN 14082:2003
(Main)Foodstuffs - Determination of trace elements - Determination of lead, cadmium, zinc, copper, iron and chromium by atomic absorption spectrometry (AAS) after dry ashing
Foodstuffs - Determination of trace elements - Determination of lead, cadmium, zinc, copper, iron and chromium by atomic absorption spectrometry (AAS) after dry ashing
This draft European Standard specifies a method for the determination of lead, cadmium, zinc, copper, iron and cromium in foodstuffs by atomic absorption spectrometry (AAS) after dry ashing at 450°C. The method describes determination in various types of foods. 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, fruit, liver and milk.
Lebensmittel - Bestimmung von Elementspuren - Bestimmung von Blei, Cadmium, Zink, Kupfer, Eisen und Chrom mit Atomabsorptionsspektrometrie (AAS) nach Trockenveraschung
Produits alimentaires - Dosage des éléments traces - Détermination du plomb, cadmium, zinc, cuivre, fer et chrome par spectrométrie d'absorption atomique (AAS) apres calcination a sec
La présente Norme européenne spécifie une méthode de détermination du plomb, du cadmium, du zinc, du cuivre, du fer et du chrome dans les produits alimentaires par spectrométrie d'absorption atomique (AAS) apres calcination a sec a 450 °C.
Cette méthode de détermination s'applique a divers types de produits alimentaires. Elle a satisfait a un essai interlaboratoires auquel ont participé 16 laboratoires [1]. Les produits alimentaires concernés par la validation de cette méthode comprennent les repas composés, les céréales, le poisson, les fruits, le foie et le lait.
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 contrôler l'existence de normes verticales.
Živila - Določevanje elementov v sledovih - Določevanje svinca, kadmija, cinka, bakra, železa in kroma z atomsko absorpcijsko spektrometrijo (AAS) po suhem sežigu
General Information
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.VHåLJXLebensmittel - Bestimmung von Elementspuren - Bestimmung von Blei, Cadmium, Zink, Kupfer, Eisen und Chrom mit Atomabsorptionsspektrometrie (AAS) nach TrockenveraschungProduits alimentaires - Dosage des éléments traces - Détermination du plomb, cadmium, zinc, cuivre, fer et chrome par spectrométrie d'absorption atomique (AAS) apres calcination a secFoodstuffs - Determination of trace elements - Determination of lead, cadmium, zinc, copper, iron and chromium by atomic absorption spectrometry (AAS) after dry ashing67.050Splošne preskusne in analizne metode za živilske proizvodeGeneral methods of tests and analysis for food productsICS:Ta slovenski standard je istoveten z:EN 14082:2003SIST EN 14082:2003en01-junij-2003SIST EN 14082:2003SLOVENSKI
STANDARD
SIST EN 14082:2003
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 14082March 2003ICS 67.050English versionFoodstuffs - Determination of trace elements - Determination oflead, cadmium, zinc, copper, iron and chromium by atomicabsorption spectrometry (AAS) after dry ashingProduits alimentaires - Dosage des éléments traces -Détermination du plomb, cadmium, zinc, cuivre, fer etchrome par spectrométrie d'absorption atomique (AAS)après calcination à secLebensmittel - Bestimmung von Elementspuren -Bestimmung von Blei, Cadmium, Zink, Kupfer, Eisen undChrom mit Atomabsorptionsspektrometrie (AAS) nachTrockenveraschungThis 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 14082:2003 ESIST EN 14082:2003
EN 14082:2003 (E)2ContentspageForeword.31Scope.32Normative references.33Principle.34Reagents.45Apparatus and equipment.56Procedure.57Calculation.88Precision.99Test report.10Annex A (informative)
Results of the interlaboratory test.11Bibliography.17SIST EN 14082:2003
EN 14082:2003 (E)3ForewordThis document (EN 14082:2003) 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 September 2003, and conflicting national standards shall be withdrawn at thelatest by September 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, iron andchromium in foodstuffs by atomic absorption spectrometry (AAS) after dry ashing at 450 °C.The method is applicable to determination in various types of foodstuffs. The method has been successfully testedin an interlaboratory trial in which 16 laboratories participated [1]. Foodstuffs covered by the validation of themethod include composite diets, cereals, fish, fruit, liver and milk.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 thepublication referred to applies (including amendments).EN 13804, Foodstuffs — Determination of trace elements — Performance criteria, general considerations andsample preparation.3 PrincipleThe samples are dry ashed at 450 °C under a gradual increase in temperature. The ash is dissolved in hydrochloricacid, and the solution obtained evaporated to dryness. The final residue is redissolved in c (0,1 mol/l) nitric acid,and the metal contents are determined by flame or graphite furnace atomic 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 14082:2003
EN 14082:2003 (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 Hydrochloric acid, not less than 37 % mass fraction, having a density of approximatelyr (HCl) = 1 190 mg/ml.4.2.1 Hydrochloric acid, c (6 mol/l). Dilute 500 ml concentrated hydrochloric acid (4.2) with water to 1 000 ml.4.3 Nitric acid, not less than 65 % mass fraction, having a density of approximately r (HNO3) =
1 400 mg/ml.4.3.1 Nitric acid, c (0,1 mol/l). Dilute 7 ml concentrated nitric acid (4.3) with water to 1 000 ml.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 1000 mg Pb in 7 ml nitric acid (4.3) in 1-l-volumetric flask.Dilute to volume with water.4.4.2 Cadmium standard solution. 1 000 mg/l. Dissolve 1 000 mg Cd in 14 ml water + 7 ml nitric acid (4.3) in1-l-volumetric flask. Dilute to volume with water.4.4.3 Chromium standard solution. 1 000 mg/l. Dissolve 3 735 mg K2CrO4 in 7 ml nitric acid (4.3) in1-l-volumetric flask. Dilute to volume with water.4.4.4 Zinc standard solution. 1 000 mg/l. Dissolve 1 000 mg Zn in 14 ml water + 7 ml nitric acid (4.3) in1-l-volumetric flask. Dilute to volume with water.4.4.5 Copper standard solution. 1 000 mg/l. Dissolve 1 000 mg Cu in 7 ml nitric acid (4.3) in 1-l-volumetricflask. Dilute to volume with water.4.4.6 Iron standard solution. 1 000 mg/l. Dissolve 1 000 mg Fe in 14 ml water + 7 ml nitric acid (4.3) in1-l-volumetric flask. Dilute to volume with water.4.5 Calibration solutions4.5.1 For graphite furnace analysisDilute standard solutions 4.4.1 to 4.4.3 with c (0,1 mol/l) nitric acid (4.3.1) to a range of standards that covers thelinear range of the element to be determined.4.5.2 Working standard solutions for flame analysisDilute standard solutions 4.4.4 to 4.4.6 with c (0,1 mol/l) nitric acid (4.3.1) to a range of standards that covers theconcentration of the element to be determined.SIST EN 14082:2003
EN 14082:2003 (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 Furnace, programmable with thermostat capable of maintaining (450 ± 25) °C. If a non-programmable furnaceis used, a separate pre-ashing device is required (see 5.5 to 5.9).5.5 Hot plate, with stepwise heating control, up to about 300 °C.5.6 Lamp, IR 250 W, fixed to a retort stand in a way that allows adjustment of the distance to the plate.5.7 Ceramic plate, e.g. dessicator plate on a low stand, with a diameter that suits the hot plate.5.8 Glass cover, e.g. crystallising dish, diameter 185 mm, height 100 mm.5.9 Wash-bottle containing sulphuric acid for purification of air.5.10 Platinum or quartz crucibles, 50 ml to 75 ml.Special attention should be paid to the crucibles. Quartz crucibles shall be stored in a mixture of concentrated nitricacid and water (1+ 9 parts by volume) then rinsed with de-ionised water before use. When necessary, thesecrucibles have to be boiled with acid as well before use. Platinum crucibles should preferably be heated until redhot and thereafter boiled with acid prior to use.5.11 Plastic bottles, with leak-proof closures, 100 ml.6 Procedure6.1 Pre-treatmentHomogenise the sample in accordance with the recommendations in EN 13804.6.2 Dry ashingWeigh a convenient amount of sample (10 g to 20 g in general) into a crucible, to the nearest 10 mg, depending onthe kind of sample. Proceed according to type of furnace.NOTECalcinations aid can be used, and validated, by the individual laboratory.6.2.1 Drying and ashing in a programmable furnace: Place the crucible with the test portion in the furnace atan initial temperature not higher than 100 °C. Increase the temperature at a maximum rate of 50 °C/h to 450 °C.Let the sample stand overnight. If there is a risk of heavy boiling make sure that the drying temperature/time issufficiently low/long. Continue according to 6.2.3.SIST EN 14082:2003
EN 14082:2003 (E)66.2.2 Drying and ashing in a non programmable furnace with thermostat and an assembly for drying/pre-ashing (hot plate with ceramic plate and glass cover + IR lamp + wash-bottle with sulphuric acid for purification ofair): See Figure 1.NOTEA programmable furnace is preferable.Key1
Infrared lamp2
Air3
Crystallising dish4
Ceramic plate5
Hot plateFigure 1 — Apparatus for pre-ashing of samplesPlace the crucible with the test portion covered with the glass cover on the ceramic plate, and let purified air comingthrough a glass tube sweep over the sample. Put the IR lamp at a distance of 30 cm to 40 cm from the sample andset the hot plate at about 100 °C. Reduce the distance as the drying proceeds until the sample can be assumed tobe dry. The lamp should then be right down at the cover.Pre-ash the sample by increasing the temperature slowly and stepwise with an IR lamp and a hot plate. The finaltemperature on the ceramic plate should then be about 300 °C. The time required for the pre-ashing varies stronglydepending on the type of sample.Put the crucible in the furnace at 200 °C to 250 °C and slowly raise the temperature to 450 °C at a rate of not morethan 50 °C/h. Let the sample stand overnight.SIST EN 14082:2003
EN 14082:2003 (E)76.2.3 Dissolution of the sample ashTake the crucible out of the furnace and let it cool. Wet the ash with 1 ml to 3 ml water, and evaporate it on a water-bath or hot plate. Put the crucible back in the furnace at no more than 200 °C and raise the temperature stepwiseto 450 °C. Proceed with the ashing at 450 °C for 1
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