DETERMINATION OF SELENIUM-COMPOUNDS IN URINE SAMPLES BY LIQUID-CHROMATOGRAPHY - INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY WITH AN ULTRASONIC NEBULIZER

An inductively coupled plasma mass spectrometer (ICP-MS) coupled with ultrasonic nebulization was used as a liquid chromatographic detector for the determination of selenium compounds. Selenite, selenate, and t rimethylselenonium were separated by ion-pair reversed-phase liquid ch romatography before introduction into the inductively coupled plasma. Detection limits were in the range of 22-74 pg selenium for various se lenium species. The relative standard deviation of the peak heights fo r five injections of 10 ng ml(-1) selenium mixture was in the range of 2-5%. This method has been applied to determine various selenium spec ies in urine samples.