Determination of selenium species in human urine by high performance liquid chromatography and inductively coupled plasma mass spectrometry

A method developed to determine organic and inorganic selenium species in human urine samples is presented in detail. After a simple sample treatment based on elimination of non-charged organic compounds, selenium species were separated by high performance liquid chromatography (HPLC) on a Spherisorb 5 ODS/AMINO column using two different chromatographic conditions: phosphate buffers at pH 2.8 and 6.0. Detection was carried out using an on-line inductively coupled plasma mass spectrometer (ICP-MS). Trimethylselenonium ion and two unknown selenium species in urine samples were found. Selenium species were shown to have stability problems, with the maximum allowed storage time of 1 week.