Fundamental Aspects of Capillary Gas Chromatography

As in all other chromatographic processes gas chromatography is based on the distribution of a component (solute) between two phases. Many chromatographers still measure the volumetric gas flow and neglect the fact that the solutes are transported through the column by the linear velocity of the carrier gas rather than the volumetric flow. Several types of solute-stationary phase interactions are important in gas chromatography. The chromatographer can become quite confused with the wide spectrum and ever increasing number of new developments of phases, which are often optimized for the separation of very specific compound pairs. Chromatography on apolar columns, however, requires more care in the purification of the samples, since polar and high boiling impurities as well as strong acids and bases are able to shorten the life span of these columns considerably. In general, polar phases allow a better separation of isomers even at minimal structural differences, and also tolerate extracts with polar impurities better.