Comparison of two digestion methods for the determination of selenium in biological samples.

Two digestion methods for the determination of selenium in biological samples have been compared: a classic digestion in a heating block by means of wet acid-ashing (HNO3-HClO4) and a microwave digestion in an open-vessel system by heating under reflux with HNO3-H2O2. The two methods were used to determine Se in plasma samples and different reference materials. There was no difference between the mean results, and the correlation coefficient for wet acid-ashing versus microwave digestion was 0.94. The two methods yielded accurate results for the certified materials analysed.