Chapter4-Gas Chromatography

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1、Chapter4GasChromatographyGraspingthecharacteristicandtheinstrumentalcomponentsofGC(2)Understandingthetheoryofcommondetectorsandtheirapplication(3)Knowingtheoperationconditionsofmobilephase(4)Graspingthequalitativeandquantitativemethods(5)AdeepreadofadvancementofGC(GCGC,HGC,PrGC,CGC)学时安排：3学

2、时Objectives:4.1ThePrincipleofGCMixtureswouldbesampledwithasyringe,vaporizedattheelevatedoventemperature,andwassweptalongthecolumnbythecarriergas.Asimpledetectorattheeffluentendofthecolumnproducedasignalproportionaltotheamountofanalyteineachelutingpeak.GS-GCGL-GCClassfication:Twomajortypes•G

3、as-solidchromatography(stationaryphase:solid)•Gas-liquidchromatography(stationaryphase:immobilizedliquid)PackedcolumnsOpentubularcolumn(capillarycolumns)P750-751Theadvantagesofcapillarycolumns(1)Thecapacityofthecapillaryismuchlessthanthatofthepackedcolumn.Leadingorfrontingpeaks?(2)Ionizatio

4、ndetectorsweredeveloped.(3)Injectionvolumeof0.5-2uL,andtheflowratewasslower.Splitinjection(4)LongcapillarycolumnscanbecoiledtofitinaGCoven.4.2InstrumentsforGCP753SampleInjectionSystemColumnsandColumnOvensCarrierGasSystemDetectionSystemsSchematicdiagramofagaschromatographyH2,N2或Ar气路系统进样系统检测系

5、统分离系统温控系统4.2.1AppearanceoftheInjectionSystemP753Syringe:5-25LVaporation(a)syringeThemostcommonwayofintroducingasampleintoaGCinstrument.(b)autosamplersMostGCinstrumentscansequentiallyanalyzeupto100ormoreliquidsampleswithoutmanualinternention.Thevialholdermovestopresenteachvialsequentiallyto

6、aGCsyringemountedinaroboticassembly.(c)Solidphasemicroexaction?Self-study!!P754(d)SplitandsplitlessinjectionsP756Splitinjection:routinemethod0.1-1%sampletocolumnremaindertowasteSplitlessinjection:allsampletocolumnbestforquantitativeanalysisonlyfortraceanalysis,low[sample](e)rotarysamplevalv

7、ewithsampleloop4.2.1CarrierGasSystemGas:N2,H2,HePurification:H2O,organiccompoundsRatecontrol:flowmeter4.2.3ColumnofGCOven4.2.4.温度控制系统温度是色谱分离条件的重要选择参数；气化室、分离室、检测器三部分在色谱仪操作时均需控制温度；气化室：保证液体试样瞬间气化；检测器：保证被分离后的组分通过时不在此冷凝；分离室：准确控制分离需要的温度。当试样复杂时，分离室温度需要按一定程序控制温度