Capillary electrophoretic determination of inorganic selenium species

The performance of pyromellitic electrolyte for capillary zone electrophoresis of inorganic selenium species in the presence of selected common anions with indirect UV detection was investigated. The separation was achieved with pyromellitic electrolyte at pH 8.8 and hexamethonium hydroxide as the electroosmotic flow modifier. Obtained detection limits of 0.17 μg ml−1 for Se(VI) and 0.29 μg ml−1 for Se(IV) were improved by a factor of 5–7 in comparison with chromate electrolyte, which has been mainly employed for selenium analysis. Good resolution for nitrate–Se(VI) peaks were obtained.