Gas Chromatography

Overview

This analytical technique is a form of chromatography that separates and detects compounds by the rate in which they move through an inert or un-reactive carrier gas such as nitrogen, helium or carbon dioxide. The time is taken (residence time) to move through the glass or metal tube called a column being used to determine the type of compound present within the sample. The gaseous compounds being analyzed interact with the walls of the column, which is coated with a stationary phase. This causes each compound to elute at a different time, known as the retention time of the compound. The comparison of retention times is what gives GC its analytical usefulness.