1、BRITISH STANDARD BS EN 1784:2003 Foodstuffs Detection of irradiated food containing fat Gas chromatographic analysis of hydrocarbons The European Standard EN 1784:2003 has the status of a British Standard ICS 67.050 BS EN 1784:2003 This British Standard, was published under the authority of the Stan
2、dards Policy and Strategy Committee on 12 August 2003 BSI 12 August 2003 ISBN 0 580 42455 3 National foreword This British Standard is the official English language version of EN 1784:2003. It supersedes BS EN 1784:1997 which is withdrawn. The UK participation in its preparation was entrusted to Tec
3、hnical 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 publications referred to in this document
4、 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 necessary provisions of a contract. Use
5、rs 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 interpretation, or proposals for change
6、, 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 21 and a back cover. The BSI copyright notice displayed in this do
7、cument indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM EN1784 August2003 ICS67.050 SupersedesEN1784:1996 Englishversion FoodstuffsDetectionofirradiatedfoodcontainingfatGas chromatographicanalysisofh
8、ydrocarbons ProduitsalimentairesDtectiondalimentsioniss contenantdeslipidesAnalyseparchromatographieen phasegazeusedeshydrocarbures LebensmittelNachweisvonbestrahltenfetthaltigen LebensmittelnGaschromatographischeUntersuchungauf Kohlenwasserstoffe ThisEuropeanStandardwasapprovedbyCENon20June2003. CE
9、NmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheManagementCentreortoanyCENm
10、ember. ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheManagementCentrehasthesamestatusasthe official versions. CENmembersarethenationalstandardsbodiesofAustria,B
11、elgium,CzechRepublic,Denmark,Finland,France,Germany,Greece, Hungary,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal,Slovakia,Spain,Sweden,SwitzerlandandUn ited Kingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:rue
12、deStassart,36B1050Brussels 2003CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.EN1784:2003EEN1784:2003(E) 2 Contents Foreword3 1 Scope 3 2 Normativereferences 3 3 Principle3 4 Reagents.4 5 Apparatus .5 6 Samplingtechnique .7 7 Procedure .7 8 Evaluatio
13、n.10 9 Limitations10 10 Validation10 11 Testreport 12 AnnexA (normative) Tables. 13 AnnexB (informative) Figures . 14 Bibliography 20EN1784:2003(E) 3 Foreword Thisdocument(EN1784:2003)hasbeenpreparedbyTechnicalCommitteeCEN/TC 275,“Foodanalysis Horizontalmethods“,theSecretariatofwhichisheldbyDIN. Thi
14、sEuropeanStandardshallbegiventhestatusofanationalstandard,eitherbypublicationofanidenticaltextor byendorsement,atthelatestbyFebruary2004,andconflictingnationalstandardsshallbewithdrawnatthelatest byFebruary2004. ThisdocumentsupersedesEN1784:1996. ThisEuropeanStandardwaselaboratedonthebasisofaprotoco
15、ldevelopedduringaconcertedactionofthe EuropeanCommission(DGXIIC.5).ExpertsandlaboratoriesfromEUandEFTAcountriescontributedjointlyto thedevelopmentofthisprotocol. Thepredecessorofthepresentstandard(EN1784:1996)hasbeenelaboratedfollowingamandateofthe EuropeanCommission. AnnexAisnormative.AnnexBisinfor
16、mative. AccordingtotheCEN/CENELECInternalRegulations,thenationalstandardsorganizationsofthefollowing countriesareboundtoimplementthisEuropeanStandard:Austria,Belgium,CzechRepublic,Denmark,Finland, France,Germany,Greece,Hungary,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal, Slova
17、kia,Spain,Sweden,SwitzerlandandtheUnitedKingdom. 1Scope ThisEuropeanStandardspecifiesamethodfortheidentificationofirradiationtreatmentoffoodwhichcontainsfat. Itisbasedonthegaschromatographic(GC)detectionofradiationinducedhydrocarbons(HC).Themethodhas beensuccessfullytestedininterlaboratorytrialsonra
18、wchicken,porkandbeef1to4aswellasonCamembert, avocado,papayaandmango5,6. Otherstudiesdemonstratethatthemethodisapplicabletoawiderangeoffoodstuffs7to28. 2 Normativereferences ThisEuropeanStandardincorporatesbydatedorundatedreference,provisionsfromotherpublications.These normativereferencesarecitedatth
19、eappropriateplacesinthetextandthepublicationsarelistedhereafter.For datedreferences,subsequentamendmentstoorrevisionsofanyofthesepublicationsapplytothisdraftEuropean Standardonlywhenincorporatedinitbyamendmentorrevision.Forundatedreferencesthelatesteditionofthe publicationreferredtoapplies(including
20、amendments). ENISO3696:1995, WaterforanalyticallaboratoryuseSpecificationandtestmethods(ISO3696:1987). 3Principle Duringirradiationchemicalbondsarebrokeninprimaryandsecondaryreactions.Inthefattyacidmoietiesof triglyceridesbreaksoccurmainlyinthe andpositionswithrespecttothecarbonylgroupsresultinginth
21、e respectiveC n1 1) andtheC n2:1 2) HC.Topredictthesechiefradiolyticproducts,thefattyacidcompositionof sampleshastobeknown(seetablesA.1andA.2). 1) C n1 :HCwhichhasonecarbonatomlessthantheparentfattyacid.EN1784:2003(E) 4 FordetectionofHCthefatisisolatedfromthesamplebymeltingitoutorbysolventextraction
22、.TheHCfractionis obtainedbyadsorptionchromatographypriortoseparationusinggaschromatographyanddetectionwithaflame ionizationdetector(FID)oramassspectrometer(MS). NOTE Asalternativeproceduresforextractionand/orpurificationofhydrocarbons,miniaturizedsolidphaseextraction (SPE)18,22,supercriticalfluidext
23、raction(SFE)27andargentationchromatography22havebeensuccessfullyemployed . Argentationchromatography22hasbeenusedeffectivelyforidentificationofradiationtreatmentofavocadoswith0,025kGy, andforprocessedsamplescontaininglowamountsofirradiatedingredients.Themethodwasalsobeneficialinreducingmatrix effect
24、se.g.withirradiatedpaprikapowder.Liquidchromatography(LC)GCMScouplinghasbeenusedsuccessfullyasan alternativeprocedureforpurificationanddetection8,17,20.Itshould,however,benotedthatthesealternativeproce dures havenotbeenvalidatedbyinterlaboratorytrials. 4Reagents 4.1General Allreagentsandmaterialsuse
25、dshallbeofrecognizedanalyticalgradethepurityofwhichhastobetested regularlybytheanalysisofblanksamples.Watershallbeofatleastgrade3accordingtoENISO3696:1995. 4.2Sodiumsulfate, anhydrous,calcinedat650C. 4.3Florisil 3) , 150mto250m(60meshto100mesh),deactivatedbyadditionofwater. Heatat550Cforatleast5horo
26、vernight(5.10)andstoreitinatightlystopperedcontainer(5.22).Ifitisnotused withinthenext3days,heattheFlorisil at130Cforatleast5h(5.21)andallowtocoolinadesiccator(5.11). Add3partsofwaterto100partsoftheadsorbent(m/m)fordeactivation.Shakethismixtureforatleast20min, andthenstoreitinastopperedcontainerfora
27、tleast10hto12hforequilibration.Usethedeactivatedadsorbent whichisfurtherstoredinastopperedcontainerinthecourseofthenext3days;afterthatreheatto130Cand followthesameprocedureasdescribedabove. 2) C n2:1 :HCwhichhastwocarbonatomslessthantheparentfattyacidandanadditionaldoublebondinposition1. 3) Florisil
28、 isanexampleofasuitableproductavailablecommercially.Thisinformationisgivenfortheconvenienceofusersof thisstandardanddoesnotconstituteanendorsementbyCENofthisproduct.EN1784:2003(E) 5 4.4nPentane 4.5nHexane 4) 4.62Propanol 4.7Isooctane 4.8Nitrogen, forconcentratingsolutions. 4.9Hydrogen,nitrogenorheli
29、um ascarriergas. 4.10 HCstandardsolution withconcentrationsofabout1g/mlto4g/mltobepreparedbydissolvinginn pentane,nhexaneorisooctane: 1dodecene(optional) 112:1 ntridecane(optional) 13:0 1tetradecene 114:1 npentadecane 15:0 nhexadecane(optional) 16:0 1hexadecene 116:1 1,7hexadecadiene 5) 1,716:2 nhep
30、tadecane 17:0 8heptadecene 5) 817:1 noctadecane(optional) 18:0 1octadecene(optional) 118:1 andifavailable 1,7,10hexadecatriene 1,7,1016:3 6,9heptadecadiene 6,917:2 4.11 nEicosanesolution (internalstandard)withaconcentrationofabout1g/mlto4g/mlofsolvent(n pentane,nhexaneorisooctane). 5Apparatus 5.1Gen
31、eral Usuallaboratoryequipmentand,inparticular,thefollowing: 5.2Electricblender and Homogenizer. 5.3Centrifuge withswingoutrotorandsuitabletubes,e.g.100ml,capableofproducingacentrifugalforceofat least900 gattheouterendofthetubes. 5.4Waterbath, capableofbeingmaintainedat50C5C. 5.5Soxhletapparatus, wit
32、hroundbottomedflaskofe.g.250mlandanextractorofe.g.100ml. 4) nHexanewasthesolventusedtovalidatethemethod.However,itisalsopossibletousenpentaneonhealthgrounds provideditcanbeshowntoleadtothesameresults . 5) TheNationalStandardizationOrganizationsinformontheavailabilityof1,716:2and817:1EN1784:2003(E) 6
33、 5.6Extractionthimbles, e.g.ofcellulose,solventwashedfordecontamination,orofglassfibre,heatedto 470Covernightfordecontamination,25mm100mm. 5.7Refluxapparatus, e.g.250mlflaskwithcondenser. 5.8Stopperedgraduatedcylinders, e.g.of100mlcapacity. 5.9Sealableglasstubes, e.g.of10mlcapacity. 5.10 Mufflefurna
34、ce, capableofbeingmaintainedat550Cand650C. 5.11Desiccator 5.12 Chromatographictube,madeofglass, havingalengthof200mmto300mmandaninternaldiameter of20mm,fittedwithafrit,apolytetrafluoroethylene(PTFE)stopcockandagroundglassjointatthetop. 5.13Graduateddroppingfunnel, e.g.of100mlcapacitywithpressurecomp
35、ensation. 5.14Pearshapedflask, e.g.of100mlcapacity. 5.15 Graduatedconicalbottomtesttubes, e.g.of10mlcapacity. 5.16 VolumetricflaskorGCflask, e.g.of1mlcapacity. 5.17 Rotaryevaporator, withevaporationflaskandawaterbathcapableofbeingcontrolledat45C. 5.18Apparatus forconcentrationofsolutionsundernitroge
36、n. 5.19Gaschromatograph(GC) equippedwithflameionizationdetector(FID)ormassspectrometer(MS). 5.20Capillarycolumn, withsuitableperformancecharacteristics,seeAnnexB. 5.21Laboratoryoven,capableofbeingmaintainedat100Cto130C 5.22Stopperedcontainer 5.23Roundbottomflasks, e.g.of250ml. 5.24Filterpaper,solven
37、twashedfordecontamination 6 Samplingtechnique Whentakingsamples,givepreferencetothosepartswhichhaveahighfatcontent(e.g.chickenskin).Keepthe sampleinasealableglasstubeorinfatfreemetalfoil.Foilshavingawaxcoatingorpackingmaterialsmadeof polyethyleneshouldnotbeused. 7Procedure 7.1Reagentblank Prepareare
38、agentblankforeveryanalysisseries. TheimpuritieswhichareencounteredaremainlysaturatedHC,whichhavebeendetectedinparticularinFlorisil , solvent,filterpaperandextractionthimbles(forSoxhletextraction).Toremoveimpurities,washfilterpaperand extractionthimblesofcellulosewithsolventuntilnoimpuritiescanbedete
39、cted.Solventblanksolutionsshouldbe concentratedbeforeanalysingthemforcontamination.Plasticsmaterialsshouldnotbeusedfortheanalyses.Only thoroughlycleanglasswareshouldbeused.EN1784:2003(E) 7 7.2Fatextractionprocedures 7.2.1 Extractionoffatfrommeatsamples 7.2.1.1General Coarselychopthesample(chickenmea
40、t,porkorbeef)andhomogenizeitinablender(5.2). Anyofthefollowingfatextractionmethodsmaybeusedsinceaparticularmethodisnotbelievedtoaffect classification. 7.2.1.2 Extractionbymelting Thisprocedureisparticularysuitableforsampleshavingahighfatcontent(chicken,pork).Therisksof contamination(7.1)areconsidere
41、dtobeverylow. Afterhomogenizingthesample(7.2.1.1),placeasuitableamount(see7.3)(upto50g,dependingonthefat content)inglasscentrifugetubes(5.3)andheatitinthewaterbath(5.4)at50C.Thephaseseparationmaybe facilitatedbyaddingasmallamount(e.g.2mlto5ml)ofwateratthisstage.Stiritoccasionallywithaglassrod, until
42、thefatphasehascompletelyvisiblyliquefied. Toseparatethephases,centrifugetheheatedhomogenatefor10minat900 g(5.3),thenremovetheupperoil phaseusingaPasteurpipette,takingcarenottodisturbtheaqueousphase(otherwise,itwillbenecessaryto centrifugethesampleagain).Iftheamountoffatextractedistoolow,loosenupthesolidphase(meat)usinga glassrodandrepeattheheatingandcentrifugationasdescribedabove. 7.2.1.3 nPentane/2propanolextraction Homogenizeequalpartsofthechoppedsample(7.2.1
