Reduction in sample foaming in purge and trap gas chromatography/mass spectrometry analyses

Determination of very volatile organic compounds in environmental water by injection of a large amount of headspace gas into a gas chromatograph

An injection method for a large amount of headspace gas which enables determination of trace amounts of very volatile organic compounds (VVOCs), dichlorodifluoromethane, chloromethane, vinyl chloride, bromomethane, chloroethane and trichlorofluoromethane in all kinds of environmental water was developed. A gas phase equilibrated with the water phase in a vial was purged with helium for a short time. The VVOCs were then introduced into a trapping tube packed with Tenax TA, which had been cooled using carbon dioxide. After trapping, the VVOCs were thermally desorbed and put into a GC-MS system for subsequent analysis. This method is applicable to various types of samples.

Quantitation of 1,1- and 1,2-dichloroethylene in body tissues by purge-and-trap gas chromatography

A sensitive and accurate method for extraction and quantitation of volatile halocarbons, i.e., 1,1- and 1,2-dichloroethylene (DCE), from body tissues has been developed. The organic volatiles were thermally desorbed from tissues contained within a Tekmar purge device, which was immersed in a stirred water bath at 60 degrees C. In order to avoid foaming, the stream of purging gas (helium) was applied 2 mm above, rather than below the sample surface in the purging device. The purged 1,1- and 1,2-DCE were retained on Tenax-GC (80-100 mesh), then desorbed by heating and vented into a Tracor 560 gas chromatograph. The detection limit of the Hall electrolytic conductivity detector operated in the halogen mode was 50 pg. Recoveries of 1,1- and 1,2-DCE from various animal tissues spiked in vitro were greater than 50%. This purge-and-trap technique appears well suited for studies of the uptake and disposition of volatile organics in body tissues.