2023年全國碩士研究生考試考研英語一試題真題（含答案詳解+作文范文）_第1頁
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1、Designation:D5974?15StardTestMethodsfFattyRosinAcidsinTallOilFractionationProductsbyCapillaryGasChromatography1ThisstardisissuedunderthefixeddesignationD5974thenumberimmediatelyfollowingthedesignationindicatestheyearofig

2、inaladoptioninthecaseofrevisiontheyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperepsilon()indicatesaneditialchangesincethelastrevisionreapproval.1.Scope1.1Thesetestmethodscoverthedeterminat

3、ionoftheamountsoftheindividualfattyacidsrosinacidsinfractionatedtalloilproductsusingcapillarygaschromatographicseparationofthevolatilemethylestersoftheseacids.1.2Fourmethodsffmingthemethylesterstwomethodsfdeterminingthea

4、mountsoftheindividualfattyacidsrosinacidsaredescribed.1.2.1Theclassicmethodfthefmationofmethylestersisthroughtheuseofdiazomethanebutdiazomethaneisahazardoustoxicmaterialsoisnolongerthepreferredreagent.Theuseofdiazomethan

5、eisdetailedintheAppendix.Methylestersmaybefmedthroughtheuseoftetramethylammoniumhydroxide(TMAH)trimethylphenylammoniumhydroxide(TMPAH)NNdimethylfmaedimethylacetal(DMFDMA).1.2.2Thetwomethodsfdeterminingtheamountoftheindiv

6、idualfattyacidsrosinacidsarethe“internalstard”methodwhichyieldsabsolutevaluesthe“areapercent”methodwhichyieldsrelativevalues.1.3Thisstarddoesnotpurpttoaddressallofthesafetyconcernsifanyassociatedwithitsuse.Itistherespons

7、ibilityoftheuserofthisstardtoestablishappropriatesafetyhealthpracticesdeterminetheapplicabilityofregulatylimitationspritouse.2.ReferencedDocuments2.1ASTMStards:2D509TestMethodsofSamplingGradingRosinD804TerminologyRelatin

8、gtoPineChemicalsIncludingTallOilRelatedProductsE691PracticefConductinganInterlabatyStudytoDeterminethePrecisionofaTestMethod3.SignificanceUse3.1Talloilfractionatedproductsderivedfromtalloilareimptantcommercialmaterialspr

9、imarilycomposedoffattyacidsrosinacidsbutalsocontainingsomeneutralmaterial(seeTerminologyD804).Fmanyapplicationsitisnecessarytoknowtheleveloftheindividualfattyacidsrosinacidspresentintheseproducts.Gaschromatographyhasprov

10、entobeausefultoolfsuchdeterminations(seeTestMethodsD509)capillarychromatographydescribedinthesetestmethodsisconsideredtobethemosteffectivegaschromatographictechniquecurrentlyavailable.Inparticularsituationsothertechnique

11、smaybemesuitablethangaschromatography.Fexamplethepresenceoffattyacidestersinthesamplewouldresultintransesterificationduringthederivatizationstepthatmayaffecttheresults.3.2Duetohydrogenbondingunmodifiedtalloilfattyacidsro

12、sinacidscannotbevolatilizedatatmosphericpressurewithoutundergoingdecomposition.Soitisnecessarytoconvertthefreeacidstothemevolatilemestablemethylesterspritochromatographicseparation.3.3Thesetestmethodsdescribefourwaystopr

13、eparemethylesters.Theclassicmethodisthroughtheuseofdiazomethanebutdiazomethaneisahazardoustoxicmaterialsoisnolongerthepreferredagent.TheuseofdiazomethaneisdetailedinAppendixX1.3.3.1TMAHcausesisomerizationofasample’sdipol

14、yunsaturatedfattyacidswhenitisusedinevenaslightexcess.Thisleadstoinaccurateresultsftheindividualfattyacidcomponents.TMAHshouldbeusedfmaterialscontainingonlyrosinacidswhentheidentificationquantitationofindividualfattyacid

15、componentsisnotimptant.3.3.2TMPAHistherecommendedmethylatingagentwhentheidentificationquantitationofindividualdipolyunsaturatedfattyacidsisrequired.TMPAHproducesresultsthatareverysimilartothoseofdiazomethanebutwithoutthe

16、hazardsthatareassociatedwithdiazomethane.AconsiderableexcessofTMPAHmaycauseisomerizationofconjugatedcompoundssimilartothatencounteredwithTMAH.1ThesetestmethodsareunderthejurisdictionofASTMCommitteeD01onPaintRelatedCoatin

17、gsMaterialsApplicationsarethedirectresponsibilityofSubcommitteeD01.34onPineChemicalsHydrocarbonResins.CurrenteditionapprovedJuly12015.PublishedAugust2015.iginallyapprovedin1996.Lastpreviouseditionapprovedin2010asD5974–00

18、(2010).DOI:10.1520D597415.2FreferencedASTMstardsvisittheASTMwebsitewww.astm.gcontactASTMCustomerServiceat.FAnnualBookofASTMStardsvolumeinfmationrefertothestard’sDocumentSummarypageontheASTMwebsite.Copyright?ASTMInternati

19、onal100BarrHarbDrivePOBoxC700WestConshohockenPA194282959.UnitedStates1phase.Therecommendedrefereecolumnis30minlength0.32mminternaldiameterwitha0.20mfilmthicknessprovidesseparationsequivalentbetterthanthatdisplayedinFig.1

20、.NOTE4—WhenusingthismethodfrefereepurposesverifythattheresolutionisadequatecomparabletothatshowninFig.1.7.3AnalyticalBalanceaccurateto0.1mg.8.ReagentsMaterials8.1PurityofReagentssee4.2.1.8.2MyristicAcid(InternalStard)99%

21、pure.NOTE5—Ahighermolecularweightsaturatedfattyacidthatelutesasamethylesterlaterinthechromatogrammaybeusedinplaceofinadditiontomyristicacidprovidedthatthealternativeinternalstardpeakdoesnotcoelutewithsamplecomponentpeaks

22、.8.3StearicAcidOleicAcidLinoleicAcidAbieticAcidDehydroabieticAcid—Otherhighpurityreferencestandardscanbeaddedasneeded.9.Procedure9.1PreparationofCalibrationStard:9.1.1Accuratelyweighintoasuitablevialmilligramquantitiesof

23、themyristicacidinternalstardplusthefattyacidrosinacidstardsthatareanticipatedtobeinthetestsamplerecdtheweights.9.1.2ConvertthecalibrationstardtothemethylesterssubstitutedammoniumsaltsasdescribedinSections456.9.2Preparati

24、onofTestSample:9.2.1Accuratelyweigh50mgofsample15mgofmyristicaciddirectlyintoasuitablevialrecdtheweight.NOTE6—Rosinsamplesneedtobefreshlybrokenfromalargermasstoensuretheresultsarenotaffectedbyairoxidationoftherosin.9.2.2

25、ConvertthetestsampletomethylesterssubstitutedammoniumsaltsasdescribedinSections456.10.SetupofGasChromatograph(GC)10.1SettheGCconditionssothattheyareapproximately(seeNote7)asfollows:Columntemperature(oventemperature)Initi

26、al150CHold5minRamp5CminFinal250CHold10minInjectionpttemperature300CInjectionptlinerglasssplitDetecttemperature325CCarriergasheliumLineargasvelocity19.5–20.5cmsSplitratio100to1maximumDetectFIDHydrogen30mLminAir400mLminMak

27、eupgas30mLminNOTE7—Thesearetypicaloperatingconditionsonly.Theindividualinstrumentshouldbeadjustedinaccdancewithmanufacturer’sinstructionstooptimizedesiredperfmance.Ongoingadjustmentsinoperatingtemperatureflowratemaybenec

28、essarytomaintainoptimumperfmanceofthecolumnduetoaging.10.2Calibration:10.2.1Inject0.5to1.0Loftheappropriatestardpreparedin9.1.10.2.2Recdtheretentiontimecalculatetheindividualrelativeresponsefactsasfollows:RRFi5WiAi3AISWI

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