ASTM D6584–00气相色谱法测定B-100生物柴油甲酯中自由甘醇和甘醇总值的试验方法

Designation:D6584–00AnAmericanNationalStandardTestMethodforDeterminationofFreeandTotalGlycerininB-100BiodieselMethylEstersByGasChromatography1ThisstandardisissuedunderthefixeddesignationD6584;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodprovidesforthequantitativedetermi-nationoffreeandtotalglycerininB-100methylestersbygaschromatography.Therangeofdetectionforfreeglycerinis0.005to0.05mass%,andtotalglycerinfrom0.05to0.5mass%.Thisprocedureisnotapplicabletovegetableoilmethylestersobtainedfromlauricoils,suchascoconutoilandpalmkerneloil.1.2ThevaluesstatedinSIunitsaretoberegardedasthestandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:D4307PracticeforPreparationofLiquidBlendsforUseasAnalyticalStandards2E355PracticeforGasChromatographyTermsandRela-tionships3E594PracticeforTestingFlameIonizationDetectorsUsedinGasorSupercriticalFluidChromatography33.Terminology3.1Definitions:3.1.1biodiesel(B-100),n—fuelcomprisedofmono-alkylestersoflongchainfattyacidsderivedfromvegetableoilsoranimalfats.3.1.2bondedglycerin,n—istheglycerinportionofthemono-,di-,andtriglyceridemolecules.3.1.3totalglycerin,n—isthesumoffreeandbondedglycerin.3.2Thistestmethodmakesreferencetomanycommongaschromatographicprocedures,terms,andrelationships.DetaileddefinitionscanbefoundinPracticesE355andE594.4.SummaryofTestMethod4.1Thesampleisanalyzedbygaschromatography,aftersilyatingwithN-methyl-N-trimethylsilyltrifluoracetamide(MSTFA).Calibrationisachievedbytheuseoftwointernalstandardsandfourreferencematerials.Mono-,di-,andtrig-lyceridesaredeterminedbycomparingtomonoolein,diolein,andtrioleinstandardsrespectively.Averageconversionfactorsareappliedtothemono-,di-,andtriglyceridestocalculatethebondedglycerincontentofthesample.5.SignificanceandUse5.1Freeandbondedglycerincontentreflectsthequalityofbiodiesel.Ahighcontentoffreeglycerinmaycauseproblemsduringstorage,orinthefuelsystem,duetoseparationoftheglycerin.Ahightotalglycerincontentcanleadtoinjectorfoulingandmayalsocontributetotheformationofdepositsatinjectionnozzles,pistons,andvalves.6.Apparatus6.1ChromatographicSystem—SeePracticeD355forspe-cificdesignationsanddefinitions.6.1.1GasChromatograph(GC)—thesystemmustbeca-pableofoperatingattheconditionsgiveninTable1.6.1.2Column,opentubularcolumnwitha5%phenylpoly-dimethylsiloxanebondedandcrosslinkedphaseinternalcoat-ing.Thecolumnshouldhaveanuppertemperaturelimitofatleast400°C.Columns,either10mor15minlength,witha0.32mminternaldiameter,anda0.1μmfilmthicknesshavebeenfoundsatisfactory.Anycolumnwithbetterorequivalentchromatographicefficiencyandselectivitycanbeused.Itisrecommendedthata2to5metre0.53mmhightemperatureguardcolumnbeinstalledfromtheinjectortotheanalyticalcolumn.Thisallowstheuseofautoinjectorsandalsoincreasescolumnlife.6.2ElectronicDataAcquisitionSystem:6.2.1IntegratororComputer,capableofprovidingrealtimegraphicanddigitalpresentationofthechromatographicdataisrecommendedforuse.Peakareasandretentiontimesshallbemeasuredbycomputerorelectronicintegration.6.2.2Thisdevicemustbecapableofperformingmultilevelinternal-standard-typecalibrationsandbeabletocalculatethecorrelationcoefficient(r2)andinternalstandardcalculationsforeachdataset.1ThistestmethodisunderthejurisdictionofASTMCommitteeD02onPetroleumProductsandLubricantsandisthedirectresponsibilityofD02.04onHydrocarbonAnalysis.CurrenteditionapprovedAug.10,2000.PublishedSeptember2000.2AnnualBookofASTMStandards,Vol05.02.3AnnualBookofASTMStandards,Vol14.02.1Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959,UnitedStates.7.ReagentsandMaterials7.1PurityofReagents—Reagentgradechemicalsshallbeusedinalltests.Unlessotherwiseindicated,itisintendedthatallreagentsconformtothespecificationsoftheCommitteeonAnalyticalReagentsoftheAmericanChemicalSocietywheresuchspecificationsareavailable.4Othergradesmaybeusedprovideditisfirstascertainedthatthereagentisofsufficientpuritytopermititsusewithoutlesseningtheaccuracyofthedetermination.7.2n-Heptane,reagentgrade.7.3N-Methyl-N-trimethylsilyltrifluoroacetamide(MSTFA),reagentgrade.7.4Pyridine,reagentgrade.7.5CarrierGas,hydrogenorheliumofhighpurity.Addi-tionalpurificationisrecommendedbytheuseofmolecularsievesorothersuitableagentstoremovewater,oxygen,andhydrocarbons.Availablepressuremustbesufficienttoensureaconstantcarriergasflowrate.7.6MicrolitreSyringes,100μland250μlcapacity.7.7ScrewCapVials,withpolytetrafluoroethylene(PTFE)-facedsepta,10mLcapacity.8.PreparationofApparatus8.1Installandconditionthecolumninaccordancewithmanufacturerorsupplier’sinstructions.Afterconditioning,attachcolumnoutlettoflameionizationdetectorinletandch