The determination of tungsten in silicate rocks

A rapid method for the determination of tungsten in silicate rocks by neutron activation analysis is presented. After irradiation and decomposition of the sample, hexavalent tungsten is adsorbed on charcoal from an acid solution as the 8-hydroxy-quinoline complex. The loaded charcoal is counted with a Ge(Li) detector. The absolute limit of determination is 10 ng. The procedure described sets the limits at 0.03 μg.g-1 for ultrabasic rocks using 300 mg samples and 0.25 μg.g-1 for other silicates, using 40 mg samples. (author)