Analysis of volatile organic compounds by cryogenic oven trapping gas chromatography

Recently, a microcomputer-controlled device for lowering oven temperature below 0℃ has become available for new types of gas chromatography (GC) instruments. This device was originally designed for rapid cooling of an oven to reduce the time for analysis. In our laboratories, we are using it for trapping volatile organic compounds (VOCs) inside a capillary column at cryogenic oven temperatures; as much as 5 ml of headspace vapor can be injected into a medium-bore capillary column without any loss, giving sensitivity 10-50 times higher than that by the conventional headspace GC method. In addition to the above high sensitivity, much better resolution (separation) of compounds can be also achieved, probably because VOCs are trapped at a cryogenic oven temperature in a quite narrow zone of the front part of a capillary column. The method is recommendable for wide use in forensic and environmental toxicology , because it is simple and requires no special GC operations in addition to the above high sensitivity and high resolution. In this review, some successful data obtained by the present capillary GC with cryogenic oven trapping are presented for analyses of chloroform, methylene chloride, trichloroethylene, ethyl ether, solvent thinner components, xylene isomers, cyanide and ethanol in human body fluids. The difference between the cryogenic oven trapping method and the cryo-focusing method is also explained.rights:日本法中毒学会rights:本文データは日本法中毒学会の許諾のもと掲載しています