Gas/liquid chromatography
Gas/liquid chromatography
- Gas/liquid chromatography (GLC) separates a mixture of volatile components.
- The mobile phase is a carrier gas; the stationary phase is a liquid on a solid.
- Each component gives a peak at its own retention time.
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.
- 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.
Practice
In GLC, the mobile phase is:
A carrier gas moves the components past the liquid stationary phase.
Practice
A component that interacts more strongly with the stationary phase has a:
More interaction slows it down, so it takes longer to pass through (longer retention time).
Reading the chromatogram
- The area of each peak gives the percentage of that component in the mixture.
Practice
The area of each peak in a chromatogram gives:
Peak area is proportional to the amount, so it gives the percentage composition.
You've got it
Key idea
- GLC: mobile phase = carrier gas; stationary phase = a non-polar liquid on a solid
- each component has a retention time; more interaction → longer retention
- the peak area = the percentage of that component