Headspace gas analysis. Quantitative trapping and thermal desorption of volatiles using fused-silica open tubular capillary traps

A system has been devised with which volatiles can be effectively trapped from headspace gas samples at relatively high flow-rates. Material is trapped in fused-silica capillary traps, 1 m in length, and coated with either an immobilized SE-30 layer, or a suitable adsorbent such as activated carbon or a powdered porous organic polymer supported on immobilized SE-30. These fused-silica traps are installed and used in stainless-steel tubes (desorption tubes) through which an electrical current is passed to effect on-line thermal desorption of the trapped volatiles. Thermal conversion of labile compounds such as α-pinene and γ-terpinene can be avoided by temperature-programmed or -controlled desorption in conjunction with cold trapping of the desorbed volatiles on the capillary column. The capacity of different traps was compared for a number of compound types and their versatility demonstrated by carrying out headspace gas determinations on, for instance, wine, urine and an imitation fruit drink. © 1986.