Abstract
A water-insoluble complexing material, 2, 5-dimercapto-1, 3, 4-thiadiazole loaded on silica gel (DMT-SG), is described for simple preconcentration of trace amounts of bismuth(III) from water samples. In batch experiments, bismuth(III) was quantitatively retained on the DMT-SG from solutions of 0.2-0.5mol dm-3 nitric acid. The complexing capacity of the DMT-SG for bismuth was 17μmol g-1 at 0.2mol dm-3 and 11μmol g-1 at 0.5mol dm-3 nitric acid. Bismuth retained on the DMT-SG column was completely eluted with 10cm3 of 0.05mol dm-3 EDTA solution; the amount was determined by a modified iodide-complexes spectrophotometry or atomic absorption spectrometry. Halogenide ions strongly hindered the retention of bismuth, due to a competitive reaction for the element with DMT. The present method is useful for preconcentrating trace amounts of bismuth from water samples containing less than 2g dm-3 of chloride ion.
