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 trimethylselenonium were separated by ion-pair reversed-phase liquid chromatography before introduction into the inductively coupled plasma. Detection limits were in the range of 22–74 pg selenium for various selenium species. The relative standard deviation of the peak heights for 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 species in urine samples.