1、ISOInternationalStandardISO7012-2Firstedition2025-03Paintsandvarnishes一Determinationofpreservativesinwater-dilutablecoatingmaterials一Part2:Determinationofin-cantotalformaldehydePeinturesetvernisDosagedesagentsdepreservationdanslesproduitsdepeinturediluablesaYeau一Partie2:Dosageduformaldehydetotalenpo
2、tReferencenumberISO7012-2:2025(en)ISO2025COPYRIGHTPROTECTEDDOCUMENTISO2025Allrightsreserved.Unlessotherwisespecified,orrequiredinthecontextofitsimplementation,nopartofthispublicationmaybereproducedorutilizedotherwiseinanyformorbyanymeans,electronicormechanical,includingphotocopying,orpostingontheint
3、ernetoranintranet,withoutpriorwrittenpermission.PermissioncanberequestedfromeitherISOattheaddressbeloworISO,smemberbodyinthecountryoftherequester.ISOcopyrightofficeCP401Ch.deBlandonnet8CH-1214Vernier,GenevaPhone:+41227490111Email:copyrightiso.orgWebsite:www.iso.orgPublishedinSwitzerlandContentsPageF
4、orewordiv1 Scope12 Normativereferences13 Termsanddefinitions14 Principle34.1 General34.2 Acidicwater-steam-distillation34.3 Derivatizationwithchromotropicacid35 Apparatus36 Reagentsandmaterials46.1 General46.2 Generalreagents46.3 ReagentsforderivatizationwithCHRA46.4 Reagentsfortitrationofformaldehy
5、destandard47 Procedure57.1 Sampling57.2 Distillation.57.3 DerivatizationusingtheCHRAprocedure57.4 Calibration57.5 Analysis57.5.1 Analysisofthecalibrationsolution57.5.2 Samplemeasurement67.6 Calculationofin-cantotalformaldehydecontent68 Precision78.1 General78.2 Repeatabilitylimit,r.78.3 Reproducibil
6、itylimit,R.79 Testreport8Annex A (normative)Titrationmethodsforthedeterminationofformaldehydecontent9Annex B (informative)Resultsoftheinterlaboratorytest11Bibliography12ForewordISO(theInternationalOrganizationforStandardization)isaworldwidefederationofnationalstandardsbodies(ISOmemberbodies).Thework
7、ofpreparingInternationalStandardsisnormallycarriedoutthroughISOtechnicalcommittees.Eachmemberbodyinterestedinasubjectforwhichatechnicalcommitteehasbeenestablishedhastherighttoberepresentedonthatcommittee.Internationalorganizations,governmentalandnon-governmental,inliaisonwithISO,alsotakepartinthewor
8、k.ISOcollaboratescloselywiththeInternationalElectrotechnicalCommission(IEC)onallmattersofelectrotechnicalstandardization.TheproceduresusedtodevelopthisdocumentandthoseintendedforitsfurthermaintenancearedescribedintheISO/IECDirectives,Part1.Inparticular,thedifferentapprovalcriterianeededforthediffere
9、nttypesofISOdocumentshouldbenoted.ThisdocumentwasdraftedinaccordancewiththeeditorialrulesoftheISO/IECDirectives,Part2(seeWWW.iso.org/directives).ISOdrawsattentiontothepossibilitythattheimplementationofthisdocumentmayinvolvetheuseof（八）patent(三).ISOtakesnopositionconcerningtheevidence,validityorapplic
10、abilityofanyclaimedpatentrightsinrespectthereof.Asofthedateofpublicationofthisdocument,ISOhadnotreceivednoticeof（八）patent(三)whichmayberequiredtoimplementthisdocument.HoweverlImplementersarecautionedthatthismaynotrepresentthelatestinformation,whichmaybeobtainedfromthepatentdatabaseavailableatWWW.iso.
11、org/patents.ISOshallnotbeheldresponsibleforidentifyinganyorallsuchpatentrights.Anytradenameusedinthisdocumentisinformationgivenfortheconvenienceofusersanddoesnotconstituteanendorsement.Foranexplanationofthevoluntarynatureofstandards,themeaningofISOspecifictermsandexpressionsrelatedtoconformityassess
12、ment,aswellasinformationaboutISOsadherencetotheWorldTradeOrganization(WTO)principlesintheTechnicalBarrierstoTrade(TBT),seeWWW.iso.org/iso/foreword.htmLThisdocumentwaspreparedbyTechnicalCommitteeISO/TC35,Paintsandvarnishes,SubcommitteeSC16,Chemicalanalysis,incollaborationwiththeEuropeanCommitteeforSt
13、andardization(CEN)TechnicalCommitteeCEN/TC139,Paintsandvarnishes,inaccordancewiththeAgreementontechnicalcooperationbetweenISOandCEN(ViennaAgreement).AlistofallpartsintheISO7012seriescanbefoundontheISOwebsite.Anyfeedbackorquestionsonthisdocumentshouldbedirectedtotheusersnationalstandardsbody.Acomplet
14、elistingofthesebodiescanbefoundatwww.iso.orH/members.htmLPaintsandvarnishesDeterminationofpreservativesinwater-dilutablecoatingmaterials一Part2:Determinationofin-cantotalformaldehyde1 ScopeThisdocumentspecifiestheapparatusandtheanalyticalmethodsfordeterminingthein-cantotalformaldehydecontentinwater-d
15、ilutablecoatingmaterials,wherethemainsourcesofformaldehydeareincanpreservatives.Thisdocumentisalsoapplicabletopolymerdispersions.2 NormativereferencesThefollowingdocumentsarereferredtointhetextinsuchawaythatsomeoralloftheircontentconstitutesrequirementsofthisdocument.Fordatedreferences,onlytheeditio
16、ncitedapplies.Forundatedreferences,thelatesteditionofthereferenceddocument(includinganyamendments)applies.ISO1513,PaintsandvarnishesExaminationandpreparationOftestsampIesISO3696,WaterforanalyticallaboratoryuseSpecificationandtestmethodsISO15528,Paints,varnishesandrawmaterialsforpaintsandvarnishesSam
17、pling3 TermsanddefinitionsForthepurposesofthisdocument,thefollowingtermsanddefinitionsapply.ISOandIECmaintainterminologydatabasesforuseinstandardizationatthefollowingaddresses: ISOOnlinebrowsingplatform:availableathttps:WWW.iso.org/obp IECElectropedia:availableathttps:/www.electropedia.org/1.1readyf
18、orusestateofaproductwhenitismixedinaccordancewiththemanufacturersinstructionsinthecorrectproportionsandthinnedifrequiredusingthecorrectthinnerssothatitisreadyforapplicationbytheapprovedmethodSOURCE:ISO11890-2:2020,3,71.2in-canfreeformaldehydecontentconcentrationofformaldehydewhichisavailableinthecoa
19、tingasanin-canpreservativef3.91asdeterminedby: methodAofthisdocument,i.e.photometricdetectionafterderivatizationwithacetylacetone; methodBofthisdocument,i.e.liquidchromatographydetectionafterderivatizationwithDNPH(2,4-dinitrophenyl-hydrazine);or methodCofthisdocumenti.e.liquidchromatographydetection
20、withpost-columnderivatizationwithacetylacetone;wherewaterisusedasanextractionsolventforallthreemethodsNote1toentry:In-canfreeformaldehydecontentcorrespondstotheamountOfformaldehydeinmilligrams,basedon1kgofcoatingmaterial(3.4)orpolymerdispersion,whichisavailableunboundinthesampleatthetimeofderivatiza
21、tion.Note2toentry:Sincethefreeformaldehydeisinequilibriumwithboundformaldehydeandtheequilibriumcanbeinfluencedbythesolvent,thecontentoffreeformaldehydeinwatercandifferfromthatinanothersolvent.Thisdefinitionforin-canfreeformaldehydecontentisonlyvalidwithrespecttowaterastheextractionsolvent.1.3in-cant
22、otalformaldehydecontentconcentrationoffreeandboundformaldehydeinthecoatingmaterial(3.4)Note1toentry:Boundformaldehydecontentistheconcentrationofformaldehyderemainingboundtothedepotsubstanceafterequilibriumisestablishedbetweenfreeformaldehydeandthedepotsubstances,andwhichcanpotentiallybereleasedbyafo
23、rmaldehydedepotsubstance.1.4coatingmaterialDEPRECATED:coatingproduct,inliquid,pasteorpowderform,that,whenappliedtoasubstrate,formsalayerpossessingprotective,decorativeand/orotherspecificpropertiesSOURCE:ISO4618:2023,3.481.5water-dilutablecoatingmaterialwater-reduciblecoatingmaterialwater-basedcoatin
24、gmaterialwater-bornecoatingmaterialwater-thinnablecoatingmaterialDEPRECATED:waterpaintcoatingmaterial(3.4)whoseviscosityisreducedbytheadditionofwaterSOURCE:ISO4618:2023,3,2721.6formaldehydedepotsubstancecompoundthatreleasesformaldehydeoveralongperiodoftime1.7extinctionattenuationofalightbeamtraversi
25、ngamediumthroughabsorptionandscatteringNote1toentry:Extinctiondependsonthewavelengthoftheradiation.SOURCE:ISO13320:2020,3.1.91.8preservativesubstancethatpreventsthegrowthofundesirablemicroorganismsSOURCE:ISO8124-7:2015,3.61.9in-canpreservativebiocideusedtopreventgrowthofmicroorganismsduringstorageof
26、astocksolutionofacoatingmaterial(3.4)orwater-basedcoatingmaterial(3.5)SOURCE:ISO4618:2023,3.1414 Principle4.1 GeneralThisdocumentdescribesaphotometricdeterminationmethodoftheformaldehydeconcentrationincoatingmaterialsafterwatervapourextractionandderivatizationwithchromatographicacid(CHRA)andsubseque
27、ntphotometricdeterminationofthecomplex.4.2 Acidicwater-steam-distillationThein-cantotalformaldehydecontentisdeterminedbyacidwater-steamdistillation,asthismethodreleasesallavailableformaldehydefromthecoatingmaterial.Whenformaldehydeboundtoaformaldehydedepotsubstanceispresentinthecoating,itiscleavedin
28、theacidicenvironmentduringwater-steamdistillationandiscollectedtogetherwiththein-canfreeformaldehydeasin-cantotalformaldehydeafterthesteamdistillationprocess.4.3 DerivatizationwithchromotropicacidInordertoenablephotometricdetectionultraviolet(UV)orvisible(VIS)offormaldehyde,derivatizationshallbecarr
29、iedouttointroducechromophores.Thein-cantotalformaldehydecontentisdeterminedphotometricallyafteraderivatizationreactionwithchromotropicacid.FormaldehydereactsinthepresenceofsulfuricacidwithtwomoleculesofchromotropicacidinorthopositiontothephenolicOHgroup.Inthesecondstep,H2SO4actsasanoxidizingagentand
30、ared,mesomericallystabilizedcarbeniumcationisformed.Theabsorptionmaximumofthecompoundisatawavelengthof578nm.5 ApparatusTheusuallaboratoryapparatusand,inparticular,thefollowingshallbeused.5.1 Watersteamdistillationapparatus,e.g.consistingofsuitableglasswareoracommerciallyavailableapparatus(e.g.Vapode
31、st20Sl).5.2 Volumetricflask,25OmLwithground-glassstopper.5.3 Precisionscale,capableofweighingtoanaccuracyof0,1g.5.4 Spectralphotometer,capableforawavelengthof578nm.5.5 Graduatedcylinders,25ml,withground-glassstoppers.5.6 Suitablepipettes.5.7 Suitablecuvettes.5.8 Suitablevolumetricflasksforcalibratio
32、n.5.9 Suitablefilter,e.g.withaporesizeof0,2m.1) Vapodest20sisanexampleofasuitableproductavailablecommercially.ThisinformationisgivenfortheconvenienceofusersofthisdocumentanddoesnotconstituteanendorsementbyISOofthisproduct.5.10 Suitablesyringes.6 Reagentsandmaterials6.1 GeneralDuringtheanalysis,unles
33、sotherwisestated,useonlyreagentsofrecognizedanalyticalgrade.6.2 Generalreagents6.2.1 Demineralizedwater,ofgrade1inaccordancewithISO3696.Sincedemineralizedwatercanleadtomicrobialcontamination,itisrecommendedtousedemineralizedwaterwithlowmicrobialcontaminationcolonyformingunits(CFU100Lortotestthatamic
34、robialcontaminationofthedemineralizedwaterhasnoinfluenceonthemeasurementresult.Formaldehydeasapreservativecanpotentiallyreactwithmicroorganisms.6.2.2 Formaldehydesolution,content(30-40)%massfraction.6.2.3 Formaldehydestocksolution,withaconcentrationofapproximately1gl.Thissolutionispreparedbydiluting
35、asuitableamountofa(30-40%massfractionofformaldehydesolution(622)withdemineralizedwater(621),andisweighedtothenearestof0,001g.Fordeterminationoftheexactformaldehydecontentoftheformaldehydesolutionoranystocksolutiondilutedfromtheoriginalformaldehydesolution,useoneofthetitrationmethodsasgiveninAnUeXA(i
36、e.theiodometricmethodspecifiedinAorthepH-valuemethodspecifiedinA.2).6.2.4 Sulfuricacidsolution,avolumefractionof25%.6.3 ReagentsforderivatizationwithCHRA6.3.1 CHRAdisodiumsalt-dihydrate(CASRNCASRegistryNumberisatrademarkoftheAmericanChemicalSociety(ACS).Thisinformationisgivenfortheconvenienceofuser
37、softhisdocumentanddoesnotconstituteanendorsementbyISOoftheproductnamed.Equivalentproductsmaybeusediftheycanbeshowntoleadtothesameresults.)5808-22-0).6.3.2 Sulfuricacid(CASRN7664-93-9),98%massfraction.6.3.3 CHRAsolution,producedbydissolvingabout(20-30mgofCHRAdisodiumsalt-dihydratef6.3.1)in4,5mlofsulf
38、uricacid(6.3.2).NOTEFormaldehydetest-kitswithCHRAsolutionarecommerciallyavailable.6.4 Reagentsfortitrationofformaldehydestandard6.4.1 Formaldehydesolution,content(30-40)%massfraction.6.4.2 Solutionofiodineinwater,0,05moll.6.4.3 Sodiumhydroxidesolutionwater,c(NaOH)=1moll.6.4.4 Hydrochloricacid,c(HCl)
39、1moll.6.4.5 Solutionofstarch,1%massfraction.6.4.6 Solutionofsodiumthiosulfateinwater,C(Na2S2O3)=0,1moll.6.4.7 AnhydrousSodiumsulfitel98%massfraction.7 Procedure7.1 SamplingPreparethesampleasspecifiedinISO1513fortestinginthe11readyforusestate.Takeatleastduplicaterepresentativesamplesoftheproducttobe
40、tested(orofeachproductinthecaseofamulti-coatsystem),asspecifiedinISO15528andprepareeachsamplefortesting.7.2 DistillationWeigh,tothenearestofO1OOIg,(105)gofwater-dilutablecoatingmaterialintoadistillationflask.Addapproximately50mlofdemineralizedwater(6.2.1).Afteracarefuladditionof(20-30mlofthe25%sulfu
41、ricacidsolution(624),thesampleissubjectedtosteamdistillation,duringwhichapproximately245mlofsolutionisoverdistilled.Fillthedistillateupto250mlwithdemineralizedwater(621).Carefuladditionofthesulfuricacidisimportanttoavoidfoaming.7.3 DerivatizationusingtheCHRAprocedureCheckifthedistillateistransparent
42、withoutturbidity.Ifthedistillateshowsturbidity,filtratethesolutionpriortothederivatizationprocesswithafilteraccordingto5.9.Add3mlofthedistillateto4,5mloftheCHRAsolutionf6.3.3)andshakethemixture.Leaveittoreactfor10minpriortothephotometricmeasurement.NOTEThemixturewillgethotduringpreparationandshaking
43、7.4 CalibrationStartingfromtheformaldehydestocksolution1623),differentdilutionstepsareperformedtocovertheworkingrangeoftheinstrument,correspondingtoapproximately0,02mg/1to8mg/1oftotalformaldehydeintheanalyticalsamplesolution.Thecalibrationiscarriedoutbyexternalstandardmethod.Preparecalibrationsolut
44、ionsforatleastfivecalibrationpoints,includingblankpoint.NOTE1Ifcommerciallyavailablecertifiedformaldehydestocksolutionisused,calibrationsolutionsarepreparedinvolumetricflasksbydilutingthestocksolutionwithwater.Thelimitofquantification(LOQ)shallbedeterminedfortheusedapparatusindividually.Itshallbeens
45、uredthattheLOQislowerthantheexpectedconcentration.Also,fortheupperconcentrationlimit,itshallbeensuredthattheexpectedformaldehydecontentlieswithintheworkingrangeofthemethod.NOTE2Dependingonthephotometerused,quantificationlimitsofupto0,1mg/kgcanbeachieved.7.5 Analysis7.5.1 Analysisofthecalibrationsolu
46、tionForeachcalibrationpoint,performthederivatizationaccordingto7.3.Theextinctionofthecalibrationsolutions,E,早t578nmforthechromotropicacidmethodisdeterminedwithrespecttotheextinctionofablanksample,E0,inaspectralphotometer.Theextinctionoftheblanksolution,0issubtractedfromtheextinctionofthesample,Eytoc
47、ompensatefortheinherentcolouringofthecalibrationsolutioncausedbytheadditionofthereagents.ThecorrectedextinctionE辛ofthecalibrationsolutionsisplottedagainsttheconcentrationofformaldehyde.Alinearregressionisperformedtodeterminetheslopeofthecalibrationcurve.ThecalibrationcurveisgivenbytheFormUIa:E1HE0=aci+b(1)whereaistheslopeofcalibrationcurveexpressedinlitrepermilligram(lmg);bistheinterceptofcalibrationcurve;zisthecalibrationsolutionindex;ciistheformaldehydeconcentrationofcalibrationsolutions,expressedinmilligramperlitre(mgl);Eiistheextinctionofcalibrationsolutioninquestion;Eoisth
