介绍气相色谱.pdf

4.GasChromatography-GC

Outline

IntroductionInstrumentation

InjectionmethodsColumns

DetectorsApplications

4.1IntroductiontoGC

Firstinstrumentalchromatographicmethod

developedcommerciallyin1958.

Reason-itisrelativelyeasytoproducea

stableflowandpressureforthe

phase-carriergas.

Allthatisreallyneededisaof

compressedgas,pressureregulatoranda

valve.

Advantagesanddisadvantages

Separationanddeterminationcanbe

realisedinasinglerun.

Highresolution(separatingalotofisomers)

Fastysis(typically,3sto30minforarun)

Relativelowyticalcost(comparedto

HPLC)

Applicabletogases,(naturalgas,refinarygas,

etc;),liquidandsolidsamples,but:

Advantagesanddisadvantages

liquidswhichcanbeevaporatedbutnot

beposedunderGCinletconditions

(typically400-500°C),and

solidswhichcanbedissolvedertain

organicsolventsandevaporatedbutnot

beposedunderGCinletconditions.

Itisestimatedthat10-20%oftheknown

compoundscanbeyzedbyGC.

4.2GCIntrumentation

Diagramofatypicalgaschromatograph

pressedgascylinder;2-paticsystem;

3-injectionsystem;4-columnsystem;5-

detectionsystem;6-electriccontrolsystem;

7-datasystem.

Gaschromatograph-examples

ShimadzuGC-17ASeries

Agilent6890GC/5973MSD

4.2.1Gassupply

Carriergas:

He,N,H

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