Designation:D2712−91(Reapproved2016)StandardTestMethodforHydrocarbonTracesinPropyleneConcentratesbyGasChromatography1ThisstandardisissuedunderthefixeddesignationD2712;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationof5ppmto500ppmeachofethylene,totalbutylenes,acetylene,methylacetylene,propadiene,andbutadieneinpropyleneconcen-trates.1.2ThevaluesstatedinSIunitsaretoberegardedasstandard.Thevaluesgiveninparenthesesareforinformationonly.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2E260PracticeforPackedColumnGasChromatographyF307PracticeforSamplingPressurizedGasforGasAnaly-sis3.SummaryofTestMethod3.1Arelativelylargevolumeofsampleischargedtoagaspartitionchromatographyapparatuswhichhasacolumnthatwillseparatethetracehydrocarbonconstituentsfromthemajorcomponents.Anycolumnorcombinationofcolumnsmaybeusedprovidedtheyhavethenecessaryresolutionandthedetectingsystemhassufficientsensitivity.Severalcolumnsthathavebeenfoundsatisfactoryaregivenin5.1.3.2Calculationisperformedbycalculatingtheconcentra-tionofthetracecompoundfromitsarearelativetotheareaofastandardcompoundofknownconcentration.4.SignificanceandUse4.1ThetracehydrocarboncompoundslistedinTable1mayhaveaneffectinthecommercialuseofpropyleneconcentrates,andinformationontheirconcentrationisfrequentlynecessary.5.Apparatus5.1Columns—Anycolumnmaybeusedprovideditwillresolvethetracecompoundpeakspresentinconcentrationsof20ppmormoresothattheresolutionratio,A/B,willnotbelessthan0.4,whereAisthedepthofthevalleyoneithersideofpeakBandBistheheightabovethebasel...
