Closed Loop Stripping and Cryogenic On-Column Focusing of Trihalomethanes and Related Compounds for Capillary Gas Chromatography

The activated carbon filters, commonly used for sampling and enrichment of organic volatiles in the closed loop stripping system, are thermally desorbed by inserting them into the injection port of a gas chromatograph-mass spectrometer-data system. The desorbed substances are trapped at liquid nitrogen temperature onto a “U-shaped” glass capillary, packed with Chromosorb and then transfered to the analytical column by rapid heating of the trap. Using this system, highly volatile halocarbons in drinking water were analyzed, using a glass capillary column provided with a stationary phase film thickness of 2.5 um.