1、DRAFT FOR DEVELOPMENT DD CEN/TS 14495:2003 Leather Chemical tests Determination of chromium VI content ICS 59.140.30 DD CEN/TS 14495:2003 This Draft for Development was published under the authority of the Standards Policy and Strategy Committee on 10 April 2003 BSI 10 April 2003 ISBN 0 580 41533 3
2、National foreword This Draft for Development is the English language version of CEN/TS 14495:2003. This publication is not to be regarded as a British Standard. It is being issued in the Draft for Development series of publications and is of a provisional nature because there is a need for users to
3、establish some experience with the method. It should be applied on this provisional basis, so that information and experience of its practical application may be obtained. Comments arising from the use of this Draft for Development are requested so that UK experience can be reported to the European
4、organization responsible for its conversion to a European standard. A review of this publication will be initiated 2 years after its publication by the European organization so that a decision can be taken on its status at the end of its 3-year life. Notification of the start of the review period wi
5、ll be made in an announcement in the appropriate issue of Update Standards. According to the replies received by the end of the review period, the responsible BSI Committee will decide whether to support the conversion into a European standard, to extend the life of the Technical Specification or to
6、 withdraw it. Comments should be sent in writing to the Secretary of BSI Technical Committee TCI/69, Leather and footwear, at British Standards House, 389 Chiswick High Road, London W4 4AL, giving the document reference and clause number and proposing, where possible, an appropriate revision of the
7、text. 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 may be found in the BSI Catalogue under the section entitled “Internatio
8、nal Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. Summary of pages This document comprises a front cover, an inside front cover, the CEN/TS title page, pages 2 to 10, an inside back cover and a back cover. The BSI c
9、opyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsTECHNICALSPECIFICATION SPCIFICATIONTECHNIQUE TECHNISCHESPEZIFIKATION CEN/TS14495 March2003 ICS59.140.30 Englishversion LeatherChemicaltestsDeterminationofch
10、romiumVI content ThisTechnicalSpecification(CEN/TS)wasapprovedbyCENon27October2002forprovisionalapplication. TheperiodofvalidityofthisCEN/TSislimitedinitiallytothreeyears.AftertwoyearsthemembersofCENwillberequested tosubmittheir comments,particularlyonthequestionwhethertheCEN/TScanbeconvertedintoaEu
11、ropeanStandard. CENmembersarerequiredtoannouncetheexistenceofthisCEN/TSinthesamewayasforanENandtomaketheCEN/TSavailable .It ispermiss bletokeepconflictingnationalstandardsinforce(inparalleltotheCEN/TS)untilthefinaldecisionaboutthep ossible conversionoftheCEN/TSintoanENisreached. CENmembersarethenati
12、onalstandardsbodiesofAustria,Belgium,CzechRepublic,Denmark,Finland,France,Germany,Greece, Hungary,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal,Slovakia,Spain,Sweden,SwitzerlandandUn ited Kingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEE
13、FRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2003CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.CEN/TS14495:2003ECEN/TS14495:2003(E) 2 Contents Foreword3 1 Scope 4 2 Normativereferences 4 3 Principle4 4 Definitions.4 5 Chemicals .4 6 Appa
14、ratus .5 7 Procedure .6 8 Calculationandexpressionofresults. 8 9 Accuracy.9 10 Testreport 9 AnnexA(informative)ReversedPhasematerial .10CEN/TS14495:2003(E) 3 Foreword Thisdocument(CEN/TS14495:2003)hasbeenpreparedbyTechnicalCommitteeCEN/TC289“Leather“,the secretariatofwhichisheldbyUNI. Themethoddescr
15、ibedissuitabletoquantifythechromiumVIcontentinleathersdownto10mg/kgandissuitable toshowwhetheraleathercomplieswiththecriteria“maximum10mg/kg“asitisgivene.g.bytheEuropean Commissiondecisionof17February1999fortheecologicalcriteriafortheecolabelofleatherforfootwear. AccordingtotheCEN/CENELECInternalReg
16、ulations,thenationalstandardsorganizationsofthefollowing countriesareboundtoanouncethisEuropeanStandard:Austria,Belgium,CzechRepublic,Denmark,Finland, France,Germany,Greece,Hungary,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal, Slovakia,Spain,Sweden,SwitzerlandandtheUnitedKingdo
17、m. AnnexAisinformative.CEN/TS14495:2003(E) 4 1Scope ThisEuropeanTechnicalSpecificationspecifiesamethodfordeterminingchromiumVIinsolutionsleachedfrom leatherunderdefinedconditions. 2 Normativereferences ThisTechnicalSpecificationincorporatesbydatedorundatedreference,provisionsfromotherpublications.Th
18、ese normativereferencesarecitedattheappropriateplacesinthetextandthepublicationsarelistedhereafter.For datedreferences,subsequentamendmentstoorrevisionsofanyofthesepublicationsapplytothisTechnical Specificationonlywhenincorporatedinitbyamendmentorrevision.Forundatedreferencesthelatesteditionof thepu
19、blicationreferredtoapplies(includingamendments). prEN14676,LeatherChemicaltestsDeterminationofvolatilematter ENISO3696:1995,WaterforanalyticallaboratoryuseSpecificationandtestmethods(ISO3696:1987) ENISO4044,LeatherPreparationofchemicaltestsamples(ISO4044:1998) ENISO2418:,LeatherChemical,physicalandm
20、echanicalandfastnesstestsSamplinglocation(ISO 2418:2002) ENISO2419,LeatherPhysicalandmechanicaltestsSamplepreparationandconditioning(ISO2419:2002) 3Principle SolublechromiumVIisleachedfromthesampleatpH7,5to8,0andsubstanceswhichinfluencethedetectionare removedbysolidphaseextractionifnecessary.Thechro
21、miumVIinsolutionoxidises1,5diphenylcarbazideto1,5 diphenylcarbazonetogiveared/violetcomplexwithchromiumwhichcanbequantifiedphotometricallyat540nm. Theresultsobtainedfromthedescribedmethodarestrictlydependantontheextractionconditions.Results obtainedbyusingotherextractionprocedures(extractionsolution
22、,pH,extractiontime,etc.)arenotcomparable withtheresultsproducedbytheproceduredescribedinthisTechnicalSpecification. 4Definitions ForthepurposesofthisTechnicalSpecificationthefollowingapplies: chromiumVIcontentistheamountofchromiumVIinleatherdeterminedbythismethodafterextractionwithan aqueoussaltsolu
23、tionatpH7,58,0.ChromiumVIcontentisreportedaschromiumVIinmg/kg.Incaseswherewet leathers,e.g.wetblues,areanalysed,thecontentisgiveninmg/kgbasedondrymatter(prEN14676) 5Chemicals Allreagentsusedshallhaveatleastanalyticalgradepurity. 5.1 Extractionsolution: 22,8gdipotassiumhydrogenphosphateK 2 HPO 4 .3H
24、2 Odissolvedin1000mlwater,adjustedtopH8,0 0,1with phosphoricacid(5.3).ThissolutionshallbedegassedwitheitherargonornitrogenCEN/TS14495:2003(E) 5 5.2 Diphenylcarbazidesolution: 1,0g1,5diphenylcarbazideCO(NHNHC 6 H 5 ) 2 isdissolvedin100mlacetone(CH 3 ) 2 COandmadeacidicwithone dropofglacialaceticacidC
25、H 3 COOH. Thesolutionshouldbekeptinabrownglassbottle.Theshelflifeisupto14daysat4C. 5.3Phosphoricacidsolution: 700mlophosphoricacidd=1,71g/ml,madeupto1000mlwithdistilledwater. 5.4 ChromiumVIstocksolution: 2,829gpotassiumdichromate(K 2 Cr 2 O 7 )(5.8),isdissolvedintowaterinavolumetricflaskandmadeupto1
26、000ml withwater.1mlofthissolutioncontains1mgofchromium. 5.5 ChromiumVIstandardsolution: 1mlofsolution(5.4),ispipettedintoa1000mlvolumetricflaskandmadeuptothemarkwithdistilledwater.1ml ofthissolutioncontains1gofchromium. 5.6 Argonornitrogen, oxygenfree 5.7 DistilledwaterofGrade3(ENISO3696:1995) 5.8 P
27、otassiumdichromate(K 2 Cr 2 O 7 ), driedfor16h 2hat102C 2C 5.9Methanol 6Apparatus 6.1Suitablemechanicalshaker,50revmin 1 to150revmin 1 6.2Conicalflask,250ml,withstopper 6.3Aerationtubeandflowmeter 6.4pHmeterwithglasselectrode 6.5Membranefilter,0,45mporesize(TeflonorNylon) 6.6Volumetricflasks,25ml,10
28、0ml,1000ml 6.7Pipettes,nominalvolumes0,5/1,0/2,0/5,0/10/20/25ml 6.8Spectrophotometerorfilterphotometer,wavelength540nm 6.9Photometriccell,quartz,2cmpathlengthoranyothersuitablecellpathlength 6.10 Glassorpolypropylenecartridgesfilledwithsuitablereversedphasematerials,e.g.RP18 6.11 SPEsystem(SolidPhas
29、eExtraction)withvacuumdeviceorsolventresistantmedicalsyringe.CEN/TS14495:2003(E) 6 7Procedure 7.1Samplingandpreparationofsamples IfpossiblesampleinaccordancewithENISO2418andgrindleatherinaccordancewithENISO4044.Ifsampling inaccordancewithENISO2418isnotpossible(e.g.leathersfromfinishedproductslikesho
30、es,garments)details aboutsamplinghavetobegiveninthetestreport. ConditionthegroundtestsampleinaccordancewithENISO2419priortoweighting. 7.2 Preparationofanalyticalsolution Weigh2g0,01gofgroundleathertothenearest0,001g.Pipette100mlofdegassedsolution(5.1),intoa250ml conicalflask(6.2).andaddtheleather.Cl
31、osetheflaskwithastopper. Theleatherpowderisextractedbyshaking3h5minutesonamechanicalshaker. Thesettingsoftheshakingapparatusshallbeassuchthattheleatherpowderisinsmoothcircularmovement withoutadheringtothewalloftheflask.Toofastmovementshallbeavoided. After3hofextractioncheckthepHofthesolution.ThepHof
32、thesolutionshallbebetween7,5and8,0.IfthepHof thesolutionisnotwithinthisrangethecompleteprocedureshallbestartedagain. Immediatelyaftertheextractioniscompletedthecontentoftheconicalflaskisfilteredthroughamembranefilter intoaglassbottlewithscrewcap. 7.3DeterminationofchromiumVIinthesolutionobtainedfrom
33、theextractionprocedure Thecartridgesarepretreatedinthefollowingway:flushthecartridge(6.10)firstwith5mlmethanol(5.9), afterwardswith5mldistilledwater(5.7)anddirectlyafterwardswith10mlofextractionsolution(5.1).The cartridges(6.10)shallnotbedriedduringorafterthepretreatment. Fromthesolutionobtainedin7.
34、2,10mlaretakenandtransferredquantitativelythroughthecartridge(6.10)onan SPEsystemwithvacuumdevice(6.11).Theeluateiscollectedina25mlvolumetricflask(6.6).Thecartridgeis flushedwith10mlextractionsolution(5.1),intothe25mlflask.Theflaskismadeuptovolumewithextraction solution(5.1).ThissolutionismarkedasS
35、1 . 10mlofsolutionS 1 arepipettedintoa25mlvolumetricflask.Thesolutionisdilutedto3/4oftheflasksvolumewith extractionsolution(5.1).0,5mlofDiphenylcarbazidesolution(5.2),isaddedandafterwards0,5mlofPhosphoric acid(5.3).Theflaskismadeuptovolumewithextractionsolution(5.1)andmixedwell. Allowtostandfor15min
36、.5minMeasuretheabsorbanceofthesolutionat540nmina2cmcellagainstthe blanksolution(7.4).TheabsorbanceobtainedisregisteredasE 1 . Foreachsampleanother10mlaliquotofsolutionS 1 ispipettedintoa25mlvolumetricflaskandtreatedas describedabovebutwithouttheadditionofthediphenylcarbazidesolution(5.2).Theabsorban
37、ceofthissolutionis measuredinthesamewayasbeforeandregisteredasE 2 . 7.4Blanksolution Threequartersfilla25mlvolumetricflaskwithextractionsolution(5.1),add0,5mlofdiphenylcarbazidesolution (5.2)and0.5mlofphosphoricacid(5.3),makeuptothemarkwithextractionsolution(5.1)andmixwell.This solutionshallbestored
38、inthedark.Theblanksolutionistreatedinthesamewayastheanalyticalsolution, includingthesolidphaseextraction.CEN/TS14495:2003(E) 7 7.5Calibration Calibratingsolutionsarepreparedfromthestandardsolution(5.5).Thechromiumconcentrationinthesesolutions shouldcovertheexpectedrangeofmeasurements. Thecalibrating
39、solutionsarepreparedin25mlvolumetricflasks. Asuitablecalibrationcurveshouldbeplottedbyusingatleastablankandfourotherstandards,withintherange 0,5ml20mlofstandardsolution(5.5).Thegivenvolumesofstandardsolution(5.5),arepipettedinto25ml volumetricflasks,0,5mldiphenylcarbazidesolution(5.2),and0,5mlofphos
40、phoricacid(5.3),isaddedtoeach flask.Makeuptovolumewithextractionsolution(5.1),mixwellandallowtostandfor15min.5min. Theabsorbanceofthesolutionsismeasuredinthesamephotometriccellasthesamplesat540nmagainstthe blankobtainedin7.4. ThechromiumVIconcentrationsing/mlareplottedagainsttheabsorbancemeasured.Th
41、echromiumVI concentrationisplottedonthexaxis,theabsorbanceontheyaxis. NOTE Ininterlaboratoryteststhe2cmcellprovedtobemostsuitable.Insomecasesitmayhoweverbesuitabletouse higherorlowercellpathlength. 7.6Determinationoftherecoveryrate 7.6.1 Influenceofthematrix Thedeterminationoftherecoveryrateisimport
42、anttoprovideinformationaboutpossiblematrixeffectswhichcan influencetheresults. 10mlaliquotofthesolutionobtainedin7.2aredosedwithasuitablevolumeofchromiumVIsolutiontodouble approximatelythecontentofthechromiumVIconcentrationoftheextract(25%).Theconcentrationofthe spikingsolutionhastobeselectedinthatw
43、aythatthefinalvolumeofthespikedsolutionismaximum11ml.This solutionistreatedinthesamewayasthesample.(see7.3) Theabsorbanceofthesolutionshallbewithintherangeofthecalibrationcurve,otherwisetheprocedureis repeatedbyusingasmalleraliquot.Therecoveryrateshallbemorethan80%. 7.6.2 InfluenceoftheRPmaterial Avolumeofsolution5.5whichcorrespondstothechromiumVIcontentoftheleatherispipettedintoa100ml volumetricflaskandismadeuptovolumewithextractionsolution(5.1). Thissolutionistre
