Designation:D5296−19StandardTestMethodforMolecularWeightAveragesandMolecularWeightDistributionofPolystyrenebyHighPerformanceSize-ExclusionChromatography1ThisstandardisissuedunderthefixeddesignationD5296;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thistestmethodcoversthedeterminationofmolecularweight(MW)averagesandthedistributionofmolecularweightsforlinear,solublepolystyrenebyhigh-performancesize-exclusionchromatography(HPSEC).Thistestmethodisnotabsoluteandrequirestheuseofcommerciallyavailablenarrowmolecularweightdistribution(MWD)polystyrenestandardsforcalibration.Thistestmethodisapplicableforsamplescontainingmolecularweightcomponentsthathaveelutionvolumesfallingwithintheelutionvolumerangedefinedbypolystyrenestandards(thatis,molecularweightsgenerallyfrom2000to2000000g·mol−1).1.2TheHPSECisdifferentiatedfromtraditionalsize-exclusionchromatographySEC(alsoreferredtoasgelperme-ationchromatography(GPC))inthatthenumberoftheoreticalplatespermetrewithanHPSECsystemisatleasttentimesgreaterthanthatfortraditionalSEC(seeTerminologyD883andPracticeD3016).2TheHPSECsystemsemploylow-volumeliquidchromatographycomponentsandcolumnspackedwithrelativelysmall(generally3to20µm)micropo-rousparticles.High-performanceliquidchromatographyin-strumentationandautomateddatahandlingsystemsfordataacquisitionandprocessingarerequired.1.3ThevaluesstatedinSIunitsaretoberegardedasthestandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.SpecificprecautionarystatementsaregiveninSection9.NOTE1—ThereisnoknownISOequivalenttothisstandard.1.5Thisinternationalstandardwasdeveloped...
