Direct determination of selenium in human serum by inductively coupled plasma-collision cell-mass spectrometry

Abstract

Selenium status in humans depends on nutritional intake. To facilitate a future monitoring study with a large number of samples, an inductively coupled plasma mass spectrometry (ICP-MS) analysis method including collision cell technology was developed for the direct determination of selenium in human serum. Serum samples were diluted (1:15 v/v) with an aqueous solution containing 2-propanol, EDTA(NH(4))(2), ammonia and Triton X-100. Isotope dilution was used as the calibration method, evaluating the (78)Se/(82)Se ratio. Interference by (81)BrH(+) was corrected mathematically. Nebuliser blockage was prevented by sample centrifugation and filtration of the wash solution. Method validation was carried out using certified and spiked human sera. All values obtained for the accuracy tests were either within the certified ranges or showed recovery between 100.9% and 104.7%. Further results were relative standard deviation of 2.0% for repeatability and 3.0% for between-run precision, a limit of detection of 0.5 mug/L and a limit of quantification of 1.1 microg/L. The benefits of the new method are high accuracy combined with low sample consumption and fast sample throughput.