Preconcentration of silver from rocks by extraction with bismuth dibenzyldithiocarbamate prior to neutron activation analysis

The method developed for determining trace levels of silver in geological materials involves the extraction of silver with a toluene solution of bismuth dibenzyldithiocarbamate followed by neutron activation of the extract. At pH 2 and in the presence of 0.1M EDTA, silver is quantitatively extracted. Under these conditions only small amounts of copper are coextracted. The detection limits of silver for three different modes of neutron activation analysis: (three cycles with Ge(Li) detector, one cycle with Ge(Li) detector and one cycle with NaI(Tl) detector) were 12, 20 and 11 ng g-1, respectively. (author)