Chapter 6 - Column selection, installation, and use

Abstract

A wide range of lower-bleed stationary phases, available in different film thicknesses and column diameters, extends the gas chromatography column capacity to manipulate analytical temperatures and solute retention factors. Newly developed stationary phases permit greater selectivity through adjustments of the separation factors of key solutes. Some columns have been specifically prepared for the separation of certain classes of solute that may be unsuitable for some other classes of solutes. This mismatch is attributable to two factors: (1) the incompatibility of the solutes and the stationary phase and (2) to the use of surface pretreatments or deactivation procedures, which render that column unsatisfactory for certain solutes or types of analysis. Ease of operation and user friendliness varies inversely with column diameter. As the column diameter decreases, the system-posed challenges increase for both the analyst and the equipment. If the column is destined for a specific analysis, the length can be selected to achieve the desired degree of resolution of that pair of solutes that is most challenging in the mixture. Packed columns normally require extensive high-temperature conditioning, whereas open tubular columns rarely need the same degree of conditioning and may suffer damage when subjected to well-intentioned but ill-advised treatments.