気体/液体クロマトグラフィー

Separating a vapour

• Gas/liquid chromatography (GLC) separates a mixture of volatile components.
• The mobile phase is a carrier gas 载气; the stationary phase is a liquid on a solid.
• Each component leaves a peak at its own retention time 保留时间.

How it works

• the stationary phase is a high-boiling-point non-polar liquid on a solid support.
• the mobile phase is an unreactive carrier gas (e.g. nitrogen).
• the retention time is how long a component takes to pass through.
• A component that interacts more with the stationary phase has a longer retention time.

A gas-liquid chromatogram 色谱图 with retention times and peak areas

Reading the chromatogram

• The area of each peak gives the proportion of that component in the mixture.

Identifying the components

• A peak's retention time matches a known standard run in the same conditions → that names the component.
• Coupling GLC to a mass spectrometer 质谱仪 (GC–MS) confirms each component's identity from its mass spectrum.
• GC–MS is the workhorse of forensics, drug testing and airport security.

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