EVALUATION OF A PURGE-AND-TRAP INJECTION SYSTEM FOR CAPILLARY GAS-CHROMATOGRAPHY MICROWAVE-INDUCED PLASMA-ATOMIC EMISSION-SPECTROMETRY FOR THE DETERMINATION OF VOLATILE SELENIUM-COMPOUNDS IN WATER

A method is presented for the selective determination of the volatile selenium species dimethylselenide and dimethyldiselenide, using a comm ercially available purge-and-trap injection system coupled to capillar y gas chromatography-microwave induced plasma-atomic emission spectrom etry. The efficiency of the purging step was evaluated and the paramet ers affecting the purge and trap processes were optimized. The method was applied to the determination of volatile selenium compounds in lak e water. Relative detection limits of 2 ng/l for dimethylselenide and dimethyldiselenide, corresponding to an absolute detection limit of 10 pg, were achieved.