BS EN 14083-2003 Foodstuffs - Determination of trace elements - Determination of lead cadmium chromium and molybdenum by graphite furnace atomic absorption spectrometry (GFAAS) aft.pdf

1、BRITISH STANDARD BS EN 14083:2003 Foodstuffs Determination of trace elements Determination of lead, cadmium, chromium and molybdenum by graphite furnace atomic absorption spectrometry (GFAAS) after pressure digestion The European Standard EN 14083:2003 has the status of a British Standard ICS 67.050

2、 BS EN 14083:2003 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 24 April 2003 BSI 24 April 2003 ISBN 0 580 41655 0 National foreword This British Standard is the official English language version of EN 14083:2003. The UK participation in it

3、s preparation was entrusted to Technical Committee AW/-/3, Horizontal analysis, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publica

4、tions referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the neces

5、sary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the inter

6、pretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 14, an inside back cover and a b

7、ack cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM EN14083 April2003 ICS67.050 Englishversion FoodstuffsDeterminationoftraceelementsDetermin

8、ationof lead,cadmium,chromiumandmolybdenumbygraphitefurnace atomicabsorptionspectrometry(GFAAS)afterpressure digestion ProduitsalimentairesDosagedeslmentstraces Dosageduplomb,ducadmium,duchromeetmolybdne parspectromtriedabsorptionatomiqueenfourgraphite aprsdigestionsouspression LebensmittelBestimmun

9、gvonElementspuren BestimmungvonBlei,Cadmium,ChromundMolybdnmit GraphitofenAtomabsorptionsspektrometrie(GFAAS)nach Druckaufschluss ThisEuropeanStandardwasapprovedbyCENon18December2002. CENmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Sta

10、ndardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheManagementCentreortoanyCENmember. ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytr

11、a nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheManagementCentrehasthesamestatusasthe official versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,CzechRepublic,Denmark,Finland,France,Germany,Greece, Hungary,Iceland,Ireland,Italy,Luxembourg,Malta,Netherl

12、ands,Norway,Portugal,Slovakia,Spain,Sweden,SwitzerlandandUn ited Kingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2003CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMe

13、mbers. Ref.No.EN14083:2003EEN14083:2003(E) 2 Contents page Foreword3 1 Scope 3 2 Normativereferences 3 3 Principle3 4 Reagents.4 5 Apparatusandequipment. 5 6 Procedure .6 7 Calculation7 8 Limitofquantification . 7 9 Precision.8 10 Testreport 9 AnnexA (informative) Resultsoftheinterlaboratorytest .10

14、 Bibliography 14EN14083:2003(E) 3 Foreword Thisdocument(EN14083:2003)hasbeenpreparedbyTechnicalCommitteeCEN/TC275“Foodanalysis Horizontalmethods“,thesecretariatofwhichisheldbyDIN. ThisEuropeanStandardshallbegiventhestatusofanationalstandard,eitherbypublicationofanidenticaltextor byendorsement,atthel

15、atestbyOctober2003,andconflictingnationalstandardsshallbewithdrawnatthelatest byOctober2003. AnnexAisinformative. AccordingtotheCEN/CENELECInternalRegulations,thenationalstandardsorganizationsofthefollowing countriesareboundtoimplementthisEuropeanStandard:Austria,Belgium,CzechRepublic,Denmark,Finlan

16、d, France,Germany,Greece,Hungary,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal, Slovakia,Spain,Sweden,SwitzerlandandtheUnitedKingdom. 1Scope ThisEuropeanStandardspecifiesamethodforthedeterminationoflead,cadmium,chromiumandmolybdenumin foodstuffsbygraphitefurnaceatomicabsorptions

17、pectrometry(GFAAS)afterpressuredigestion. SpecificfoodstuffsforwhichEuropeanStandardsexistareexcludedfromthescopeofthishorizontalEuropean Standard.Theanalystshallreviewifverticalstandardsexist. 2 Normativereferences ThisEuropeanStandardincorporatesbydatedorundatedreference,provisionsfromotherpublica

18、tions.These normativereferencesarecitedattheappropriateplacesinthetext,andthepublicationsarelistedhereafter.For datedreferences,subsequentamendmentstoorrevisionsofanyofthesepublicationsapplytothisEuropean Standardonlywhenincorporatedinitbyamendmentorrevision.Forundatedreferencesthelatesteditionofthe

19、 publicationreferredtoapplies(includingamendments). EN13804, FoodstuffsDeterminationoftraceelementsPerformancecriteria,generalconsiderationsandsample preparation. EN13805, FoodstuffsDeterminationoftraceelementsPressuredigestion. 3Principle Determinationoftheelementsinthetestsolutionbygraphitefurnace

20、atomicabsorptionspectrometry(GFAAS)1, 2,4afterpressuredigestionaccordingtoEN13805. WARNINGTheuseofthisstandardcaninvolvehazardousmaterials,operationsandequipment.This standarddoesnotpurporttoaddressallthesafetyproblemsassociatedwithitsuse.Itistheresponsibility oftheuserofthisstandardtoestablishappro

21、priatesafetyandhealthpracticesanddeterminethe applicabilityofregulatorylimitationspriortouse.EN14083:2003(E) 4 4Reagents 4.1General Theconcentrationofthetraceelementsinthereagentsandwater,usedshallbelowenoughnottoaffectthe resultsofthedetermination. 4.2 Hydrochloricacid, notlessthan25 %,(massfractio

22、n),havingadensityofapproximately (HCl)=1,13g/mlandsuitablefortraceelementanalysis. 4.3 Nitricacid, notlessthan65%,(massfraction),havingadensityofapproximately (HNO 3 )=1,4g/mland suitablefortraceelementanalysis. 4.4 Stocksolutions NOTE Thestocksolutionsforlead,cadmium,chromiumandmolybdenumcanbeprepa

23、redfrommetalsormetalsalts. Theycanbecommerciallyavailablealso.Itisadvisabletousecertifiedstocksolutions.Thepreparationofstocksolutionsa re givenasanexampleinthefollowing: 4.4.1 Leadstocksolution, withaleadconcentrationof1000mg/l. Dissolve1,598gofleadnitrate(Pb(NO 3 ) 2 )innitricacid1%(10mlaccordingt

24、o4.3dilutedwithwaterto1000ml) andmakeupwithnitricacid1%to1000ml. 4.4.2 Cadmiumstocksolution, withacadmiumconcentrationof1000mg/l. Dissolve1,000gofcadmiummetalinaminimumamountofhydrochloricacid1%(10mlaccordingto4.2and dilutedwithwaterto1000ml)andmakeupto1000mlwith1%(partsbyvolume)hydrochloricacid. 4.

25、4.3 Chromiumstocksolution, withachromiumconcentrationof1000mg/l. Dissolve3,735gofpotassiumchromate(K 2 CrO 4 )inwaterandmakeupwithwaterto1000ml. 4.4.4 Molybdenumstocksolution,withamolybdenumconcentrationof1000mg/l. Dissolve1,840gofammoniumheptamolybdate(NH 4 ) 6 Mo 7 O 24 . 4H 2 O)inammoniasolution1

26、%(10mlammonia solutionofmin25%, (NH3) =0,91g/ml,dilutedwithwaterto1000ml)andmakeupwithammoniasolution1%to 1000ml. 4.5 Calibrationsolutions Dilutethestocksolutionstotheconcentrationsneededforcalibration;theconcentrationsshallbechosensoasnot toexceedthelinearrangeofthecalibrationfunction.Itisrecommend

27、edtouseaminimumof3calibrationsolutions withdifferentconcentrations.Theconcentrationofacidinthecalibrationsolutionsshallbeequaltothatinthetest solution(seeEN13805). 4.6 Zeromembercompensationsolutions, whichshallcontainwaterandanamountofacidwhichis equaltotheacidconcentrationinthetestsolution.EN14083

28、:2003(E) 5 4.7Modifier 4.7.1General Theexamplesofmodifierslistedbelowmayvaryconsiderablybothincombinationandinconcentration.The recommendationofthemanufactureroftheapparatusshallbetakenasastartingpointforsubsequent optimisation.Insteadofthesolutionsaccordingto4.7.2to4.7.5,commercialmagnesiumnitratea

29、ndpalladium nitratesolutionsmaybeused. NOTE Theanalystshouldbeawarethatthespecificuseofmodifiersforagivenelementshouldbeappliedduring establishmentoftheoptimumfurnacetemperatureprogram. 4.7.2 Magnesiumnitratesolution Dissolve0,25gofmagnesiumnitratehexahydrate(Mg(NO 3 ) 2 6H 2 O)in100mlofwater. 4.7.3

30、 Palladium/magnesiumnitratesolution Dissolve0,075 gofpalladiumin2 mlofhotnitricacid(4.3),diluteto25 mlwithwater,add0,05 gof Mg(NO 3 ) 2 6H 2 Oandmakeupto50mlwithwater. 4.7.4 Ammoniumphosphate/magnesiumnitratesolution Dissolve0,5gofammoniumdihydrogenphosphate(H 2 NH 4 PO 4 ) inwater,add0,05gofMg(NO 3

31、 ) 2 6H 2 Oand1ml nitricacid4.3andmakeupto50mlwithwater. 4.7.5 Palladium/ascorbicacidsolution SolutionA:add500 m lofhydrochloricacid(4.2)to1mlofapalladiumstocksolutioncontaining10gofpalladium perlitreandmakeupto10ml. SolutionB:dissolve1gascorbicacidin100mlofwater. Preparethepalladium/ascorbicacidsol

32、utionbymixingonepartbyvolumeofsolutionAwithonepartbyvolumeof solutionB. 5 Apparatusandequipment 5.1General Tominimisethecontamination,allapparatuswhichcomesintodirectcontactwiththesampleandthesolutions shouldbecarefullypretreatedaccordingtoEN13804. 5.2 Atomicabsorptionspectrometer Withbackgroundcorr

33、ection(Zeemancorrectionisrecommended),graphitefurnacesuppliedwithargonandwitha measurementrecordingsystem. 5.3 Graphitetubes Recommendation, pyrolyticallycoatedtubeswithorwithoutLvovplatform.EN14083:2003(E) 6 5.4 Automaticsampleinjector 5.5Elementspecific lamps (hollowcathodeorelectrodelessdischarge

34、lamps)forlead,cadmium,chromium andmolybdenum. 6Procedure 6.1 Samplepreparation ThetestsolutionobtainedbythepressuredigestionmethodaccordingtoEN 1 3805maybeusedforthe determinationwithoutfurthertreatment. 6.2 Atomicabsorptionspectrometry(graphitefurnaceAAS) 6.2.1Spectrometer settings Beforeeverydeter

35、mination,adjusttheinstrumentasspecifiedinthemanufacturersoperatingmanual.Then determineanoptimumtestschedule(ifpossibleusingasamplematrix),takingintoaccount,inparticular,of parameterssuchasdecompositiontemperatureandtime,atomizationtemperatureandtime.Inadditionmatrix modificationandinjectedvolumesco

36、uldbechecked.Examplesofsomeinstrumentparametersaregivenin Table1: Table1Instrumentparameters Parameter Lead Cadmium Chromium Molybdenum Radiationsource Hollowcathodelamp Wavelength 283,3nm 228,8nm 357,9nm 313,3nm Slit 0,7nm 0,7nm 0,7nm 0,7nm 6.2.2AASdetermination 6.2.2.1General Theabsorbanceisdeterm

37、inedforanaliquotofthetestsolutionbyatomicabsorption.Ifthereisnosignificant differencebetweentheslopeofthecalibrationfunctioninthecaseofthestandardadditionmethodandthe calibrationmethod,thelattercanbeemployed.Interferencescanbereducedbyusingmatrixmodifiers(asin4.7) inconjunctionwiththeLvovplatform. N

38、OTE Thedataaquisitionduringtheatomisestepcanbeperformedbypeakheightorpeakareameasurement.When usingplatformtechnique,peakareameasurementisrecommended. 6.2.2.2 Calibrationmethod Setthezerooftheinstrumentusingthezeromembercompensationsolutionsaccordingto4.6.Deriveacalibration functionforeachelementbym

39、easuringtheabsorbancesofthecalibrationsolutionswithdifferentelement concentrations.Plottheabsorbancesobtainedagainsttheconcentrationsinagraph. NOTE ModernAASinstrumentsarecapableofderivingthecalibrationcurvesthemselvesanddisplaythemeasurement forthesampledirectlyinconcentrationunits.EN14083:2003(E)

40、7 Findthelinearrangeofthecalibrationfunctionforeachelementandcheckitregularly.Carryoutthecalibration withinthelinearrangeusingthecalibrationsolution,takingaccountoftheconcentrationoftheelementinthe digestionsolution.Thedeterminationcannowbecarriedoutusingthedigestionsolution,eitheruntreatedor,ifthe

41、concentrationisoutsidethelinearrange,aftersuitabledilution.Checkthezeromembercompensationsolutions andindividualcalibrationsolutionsinthecourseoffairlylongseriesofmeasurements. 6.2.2.3 Standardadditionmethod Determinethelinearrangeofthecalibrationfunctionasinthecaseofthecalibrationmethod(6.2.2.1). I

42、tisimportantthatthemeasurementsaremadeinthelinearrangewhenthemethodofstandardadditionisused.A standardadditioncurveshouldconsistofatleastthreepointsofwhichatleasttwoarestandardadditions.The concentrationofthehigheststandardshouldbe3 to 5timestheconcentrationinthesamplesolution.The concentrationofthe

43、lowerstandardshouldbehalfofthehigheststandard. Plotagraphoftheabsorbancesobtainedinthiswayagainsttheaddedconcentrationsandextrapolatethe resultingstraightlineuntilitinterceptstheconcentrationaxis. InthecaseofAASinstrumentswithautomaticsampleinjectionsystems,inwhichtheadditiontakesplacedirectly intothegraphitefurnace,thedeterminationcanbecarriedoutwithoutpriordilutionandthissubstantiallyeliminates theriskofcontamination. 6.3 Analyticalqualitycontrol Foranalyticalqualitycontrol,blanksolutionsandreferencesampleshavingrelia