Preparative gas chromatography as a sample preparation approach

Preparative gas chromatography (prep-GC) has been a valuable tool for sample preparation, primarily to increase the mass of an individual compound, or zones of compounds isolated from a sample, for the purposes of further chemical analysis. A preparative step involving large and repetitive injected amounts of sample can precede improved or precise spectroscopic analysis of a single compound, usually where the spectroscopic step is either insufficiently sensitive or cannot be hyphenated with the GC instrument. The preparative step is also useful when compounds cannot be readily concentrated before the GC analysis, to allow a greater mass to be introduced to a subsequent analytical GC measurement step. Both approaches provide considerable opportunity either for discovery of the identity of trace compounds that were previously below instrument detection limits or identification of molecular structure that requires more powerful spectroscopic characterization procedures.