Gas Chromatography: Introduction

In gas chromatography or GC, the sample is first vaporized and mixed with a carrier gas such as helium, nitrogen, or argon.

This forms the gaseous mobile phase that flows through a column containing the stationary phase.

In gas–liquid chromatography or GLC, solid support particles are coated with a nonvolatile, thermally stable, chemically inert liquid stationary phase.

The elution order of components is primarily determined by their boiling point, where solutes with lower boiling points elute first.

In gas–solid chromatography columns, solid particulates, such as diatomaceous earth, are used as the stationary phase and support.

These materials have high porosity and surface area and retain analytes via adsorption, resulting in large distribution coefficients and efficient separations.

However, the nonlinear adsorption process results in severe tailing of elution peaks.

So, GSC is mainly used for permanent gases and small polar molecules not retained by gas-liquid columns.