BRAINCAKEGas Chromatography
Gas chromatography (GC) separates volatile components of a mixture, and is sensitive enough to detect very small amounts.
• The mobile phase is an unreactive carrier gas, such as helium or nitrogen.
• The stationary phase is a high-boiling liquid coated on an inert solid support (or on the inside wall) inside a long, thin, coiled capillary column.
• The column is kept inside an oven so the sample stays as a gas.
A small sample is injected, vaporises and is carried through the column by the carrier gas. Components separate by their relative solubility in the liquid stationary phase: a component that is more soluble in the liquid spends longer dissolved in it and moves through the column more slowly.
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
Key terms in this lesson
- stationary phase
- The phase in chromatography that does not move, and interacts with the components of a mixture to different extents.
- mobile phase
- The phase in chromatography, a liquid solvent or gas, that moves through or over the stationary phase carrying the mixture's components.
More in Chromatography and Qualitative Analysis
- Chromatography
- Thin-Layer Chromatography
- Rf Values
- Retention Times and Peak Areas
- Qualitative Tests for Alkenes
- Qualitative Tests for Haloalkanes
- Qualitative Tests for Phenols
- Qualitative Tests for Carbonyls
All 10 lessons in Chromatography and Qualitative Analysis · All OCR A-level Organic Chemistry topics