Introduction

High speed gas chromatography (GC) has been the subject of an increasing number of papers in both journals and at conferences in recent years. These articles have progressed from concept papers mainly detailing the necessary instrumental modifications to the potential applications of high speed GC.

This article is focused on reported applications of what may be regarded as traditional high speed GC, i.e. short, wall-coated open tubular columns (generally of internal diameter (i.d.) <0.32 mm) operated at a higher than optimal carrier gas flow rate. The total chromatographic separation time is required to be less than 3-4 min. This eliminates some work on polychlorinated biphenyl separations where run times are approximately six times faster than conventional GC, but still take around 10 min. Other areas in high speed GC, such as rapid packed column separations, porous layer open tubular columns and the newly emerging imaging technique of solvating GC using packed columns will not be addressed. In addition, only those articles which specifically relate to the use of high speed GC for a particular analysis have been considered. The separation of a large number of compounds by high speed GC has been demonstrated in many research articles, but many of the mixtures separated are not specific to any particular problem or truly relevant to real world analysis.

High speed GC is still mainly an academic research technique. The number of published applications is small and review articles or books detailing these applications are nonexistent. For this reason this article draws mainly on journal papers.

High speed GC is not a new analysis technique. The first true high speed separations involving capillary columns were carried out nearly four decades ago by Desty. Although this clearly demonstrated that separations in seconds were possible, the instrumental demands that high speed GC makes upon the gas chromatograph made it unsuitable for general use at that time. In the following years several notable research groups around the world have made excellent progress both in solving some of the instrumental problems and in clarifying the theoretical considerations involved with high speed GC. In particular, the major contributions of Annino and Guiochon to theoretical developments and the research groups of both Cramers and Sacks for instrumental advances deserve specific mention.

There are several reasons for this slow transfer of high speed GC from the research laboratory to the analytical laboratory. One is the reluctance of application laboratories to substitute a new untried procedure for a known analytical method, even when the new procedure offers major time savings. New methods frequently encounter this hurdle and as more literature reports on high speed GC applications appear, this barrier should slowly crumble.

Another barrier, which will be harder to overcome, is the problem of sample preparation. The advantages of a very fast chromatographic separation are negated if the sample preparation step takes an order of magnitude or more longer than the separation. Further basic research is required in the sample preparation area to bring these two stages closer inline with each other. The workers who have pioneered high speed GC research in the last decade are already incorporating faster sample preparation steps into their research and it is likely that the coming years will see the progress needed in this area.

To date, most high speed GC applications have been in the analysis of volatile organic chemicals (VOCs) in either air or water. Other applications include chlorinated pesticides, polyaromatic hydrocarbons (PAHs), and the use of high speed GC to determine solvent purity. Each of these areas will be considered in more detail below.

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