Analysis of Food Volatiles Using Headspace–Gas Chromatographic Techniques

Gas chromatography (GC) involves the analysis of volatile organic compounds, that is, materials that exist in the vapor phase, at least at the typical GC operating temperatures between 40 and 300°C. Headspace sampling techniques are frequently divided into three broad categories: static headspace, dynamic headspace, and purge and trap. The controlled analysis of vapors that have migrated into an atmosphere from some solid or liquid source forms the basis of static headspace analysis. Many organic compounds can be removed from a stream of gas by passing them through a tube packed with a finely divided sorbent material. Most sorbent materials are porous polymers similar to the kinds of materials used to fill packed GC columns for gas analyses. Tenax is perhaps the most widely used, general purpose sorbent for dynamic headspace techniques. The condensation units produce an intentional cold spot in the pneumatics of the system, providing an area for water to condense out of the carrier.