ROUTINE DETERMINATION OF MERCURY, ARSENIC AND SELENIUM BY RADIOCHEMICAL NEUTRON-ACTIVATION ANALYSIS

A method for the determination of mercury, arsenic and selenium by neutron activation analysis is described. Radiochemical separations are performed by selective distillation followed by electrolysis of mercury on gold and precipitation of arsenic and/or selenium by reduction to the elemental form. The chemical yields are 80-90% for mercury and 90-100% for arsenic and selenium. Interference tests have been carried out with reference to those elements most likely to interfere with the analysis. Detection limits for mercury, arsenic and selenium using 0.1 g of sample are 0.2 ng g-1, 2 ng g-1 and 3 ng g-1, resp. Detection limits can be improved using greater sample size and neutron flux density. Results from the analysis of several NBS standard reference materials are given.