Designation:D2426−93(Reapproved2014)StandardTestMethodforButadieneDimerandStyreneinButadieneConcentratesbyGasChromatography1ThisstandardisissuedunderthefixeddesignationD2426;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationofbutadienedimer(4-vinylcyclohexene-1)andstyreneinbutadieneconcentrates,bothrecycleandspecificationgrade.1.2ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.ForspecificprecautionarystatementsseeSections6and8.2.ReferencedDocuments2.1ASTMStandards:2D1657TestMethodforDensityorRelativeDensityofLightHydrocarbonsbyPressureHydrometerD1945TestMethodforAnalysisofNaturalGasbyGasChromatographyD2593TestMethodforButadienePurityandHydrocarbonImpuritiesbyGasChromatography2.2OtherDocuments:2STP109APhysicalConstantsofHydrocarbonsC1toC103.SummaryofTestMethod3.1Thesampleisintroducedintoagas-liquidpartitioncolumn.Thecomponentsofinterestareseparatedastheyaretransportedthroughthecolumnbyacarriergas,andtheirpresenceintheeffluentisdetectedandrecordedasachromato-gram.Packedcolumnsareused,andeitherthermalconductiv-ityorionizationdetectorsarepermissible.Thequantityofthecomponentsofinterestpresentinthesampleisdeterminedfromthechromatogrambycomparingtheirpeakareasorheightswiththoseobtainedfromasyntheticsample.4.SignificanceandUse4.1Butadienedimerandstyrenemaybepresentasimpuri-tiesincommercialbutadiene.Thistestmethodissuitableforuseininternalqualitycontrolandinestablishingproductspecifications.5.Apparatus5.1Chromatograph—Anychromatogr...
