Abstract
A combined method of dithizone-extraction and carbon powder column adsorption was applied to concentrate trace amounts of copper (II) and mercury (II) in natural water samples before neutron activation analysis.
The sample solution was adjusted to pH 1.0 with nitric acid, an aliquot of which was taken in a 500 cm3 separating funnel and then 5.0 cm3 of 0.01% dithizone-benzene and 25 cm3 of n-hexane were added. The mixture was shaken for 10 min and stood for 30 min. After the aqueous phase was discarded, another aliquot of the sample solution was added. The above procedure was repeated until the treatment of the sample solution (1.00 dm3) was completed. The organic phase was then flown through the column (6 mmφ×50 mmh) containing carbon powder, and the resulting column was dried. The monitor containing 10 μg of mercury or copper was also prepared according to the above procedure. The samples and monitors were irradiated together in a pneumatic tube of JRR-3. After cooling, copper and mercury were determined by γ-spectrometry using 64Cu, 197Hg, respectively.
The recovery of trace metal ions obtained by this method was more than 99%, and the present method was found to be applicable to the preconcentration of copper (II) and mercury (II) in natural water samples.
