Gas Chromatography with Glass Capillary Columns

"Chromatography" is a general term for separation processes in which the components of a mixture are repetitively equilibrated between two phases; normally one of these phases is fixed or stationary, and the other is mobile. When the mobile phase is a gas, either a liquid or a solid can be utilized as the stationary phase; these processes are most precisely termed " gas - liquid partition chromatography," and " gas - solid partition chromatography," respectively. The former, to which we will confine our attention, is generally termed simply " gas chromatography" or " G C . " Occasionally one still sees the expression " G L C " (gasliquid chromatography) or " V P C " (vapor-phase chromatography), but with a few exceptions these exist largely in the older literature. In the process of gas chromatography the stationary liquid phase is confined to a long tube, the column, in which it exists as a thin film which is either distributed over an " inert " granular support (packed columns) or supported as a thin coating on the inner surface of the column (wall-coated open tubular columns).