Designation:D4450−85(Reapproved2012)StandardTestMethodforAnalysisofZincHydroxyPhosphitePigment1ThisstandardisissuedunderthefixeddesignationD4450;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodisintendedforthedeterminationofzincoxideandphosphorousacidcontentofthepigmentcommerciallyknownaszinchydroxyphosphite.Thezinccontentisdeterminedbyethylenediaminetetraacetate(EDTA)titrationandcalculatedaszincoxide(ZnO),whilethephos-phoruscontentisdeterminedcolorimetricallyandcalculatedasphosphorousacid(H3PO3).1.2Theanalyticalproceduresappearinthefollowingorder:SectionsZincoxide6through8Phosphorousacid9through141.3ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D1193SpecificationforReagentWater3.SummaryofTestMethod3.1Thezincisdeterminedbydissolvingthetestsampleinnitricacid,adjustingthepHofthesolutionto5to5.5andtitratingwithEDTA.3.2Thephosphorusisdeterminedcolorimetricallywiththeaidofnitricacid,ammoniumvanadate,andammoniummo-lybdate.Theabsorbanceofthetestsampleiscomparedtoacalibrationcurvethatyieldsthenumberofmilligramsofphosphorus.4.SignificanceandUse4.1Thistestmethodmaybeusedtoconfirmthestatedzincoxideandphosphorousacidcontentofzinchydroxyphosphitepigment.5.PurityofReagents5.1Reagentgradechemicalsshallbeusedinalltests.Unlessotherwiseindicated,itisintendedthatallreagentsshallconformtothespecificationsoftheCommitteeonAnalyticalReagentsoftheAmericanChemicalSociety,wheresuchspecificationsareavailable.3Othergradesmaybeused,...
