This Gas Chromatography – Mass Spectrometer Schematic helps the reader follow the explanation of how this analysis technique works.
A gas or liquid is injected into the Gas Chromatograph side of the GC-MS system. Its component chemicals are separated by a capillary column of great length in an oven. The capillary walls are coated with substances that weakly adsorb either polar or non-polar compounds. These substances desorb and then adsorb again many times as they are carried down the column by helium gas. Lighter molecules usually arrive at the detector earlier than do heavier molecules. Two types of detectors are used, either a flame ionization detector or a thermal conductivity detector. The separated compounds can also be fed into the mass spectrometer, where they are ionized and the ions created are analyzed by their charge to mass ratios.
