Simultaneous speciation of arsenic, selenium, antimony and tellurium species in waters and soil extracts by capillary electrophoresis and UV detection

Abstract

Capillary electrophoresis with indirect UV detection was used to determine simultaneously arsenic, selenium, antimony and tellurium compounds. The separation was achieved in a fused silica capillary filled with an electrolyte solution containing sodium chromate and an electroosmotic flow modifier, trimethyltetradecylammonium hydroxide (TTAOH). The effect of the TTAOH concentration and electrolyte solution pH on the electrophoretic mobility of the species was studied. The best simultaneous separation of these species was achieved with 0.5 mM TTAOH and an electrolyte pH of 11.2 within 5 min. Detection limits range from 13 µg l^–1 for Se^VI to 509 µg l^–1 for Te^IV with electromigrative injection. The reproducibility was below 10% and linearity was verified in the 0–100 mg l^–1 range for all species. Interferences by other inorganic ions were studied. This method was applied to the determination of metalloids in a spiked drinking water. Water extracts of industrial soils were analysed and results were compared with those of ICP-MS measurements.