Determination of selenium in sediments by inductively coupled plasma-mass spectrometry:: high resolution versus hydride generation

Two approaches were compared for the determination of Se in two marine sediments (MESS-2 and the round robin sample IMEP-14). A special hydride technique was used to minimize chemical interferences. The technique is based on a double loop flow injection-hydride system with a short reaction time of 100 ms, followed by immediate separation of the volatile products. In order to ensure a quantitative reduction of selenium, a pre-reduction had to be done to convert all Se to Se(IV). The hydride system was coupled to a quadrupole ICP-MS. Another promising method is the direct determination of Se using a sector field ICP-MS. High resolution and good stability of the mass calibration are important for such determinations. With both approaches, it was possible to find the certified value of the reference material within the measurement uncertainty.