The basic principle of Gas Chromatography (GC) is the separation of compounds based on how they distribute between two phases:
- A mobile phase — an inert carrier gas (like helium or nitrogen).
- A stationary phase — a liquid or solid inside the column.
Simple explanation:
- The sample is vaporized and carried by the gas through the column.
- Inside the column, each compound interacts differently with the stationary phase:
- Compounds that interact strongly stay longer in the column.
- Compounds that interact weakly come out faster.
- Because of these differences, the compounds separate and reach the detector at different times (called retention times).
In short:
Gas Chromatography works by separating compounds based on how long they take to travel through a column — depending on their boiling points and interactions with the stationary phase.