Determination of mercury and selenium in biological samples by neutron activation analysis

Nuclear analytical techniques, specially neutron activation analysis (NAA) have been for a long time giving important contribution to trace element studies in the life sciences, due to their accuracy, precision, non-destructive and multielemental capabilities. In the present paper, instrumental neutron activation analysis (INAA) was applied to the. determination of Hg and/or Se in several types of biological samples such as hair, nails, fish reference materials and also in selenium supplements. The hair samples analyzed were collected from a control group and mainly from Indian populational groups living in the Amazonic region, where very high Hg contents were found (means from 3.6 to 21.8 mug g(-1)), probably due to gold exploration activities and biomass burning. A comparison was made of INAA for Se using two different radioisotopes: the short-lived Se-77m (t(1/2) = 17.45 s) and the long-lived one Se-75 (t(1/2) = 119.8 d). Both methods were applied to determination of Se in samples of hair, nails and vitamin supplements.