DETERMINATION OF SELENIUM IN MARINE CERTIFIED REFERENCE MATERIALS BY HYDRIDE GENERATION INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

The determination of Se in sea-water and in a number of marine biologi cal tissue certified reference materials by hydride generation inducti vely coupled plasma (ICP) mass spectrometry is described. Detection li mits of 2.5 pg ml-1 for Se and 0.3 pg ml-1 for As were achieved by opt imization of operating conditions and systematic reduction of blank an d background signals. Careful cleaning of the hydride generation appar atus, the central tube of the ICP torch and the skimmer was necessary in order to avoid degradation of these detection limits by memory effe cts. Selenium concentrations as low as 0.6 mug g-1 in biological tissu es and 20 ng l-1 in sea-water were successfully determined.