Research Information System
ANALYTICAL LETTERS, vol.33, no.10, pp.1975-1989, 2000 (SCI-Expanded)
Electroanalytical methods have been widely used for determination of Se(IV), but the nature of the reduction processes involved is not well understood. Polargraphic reduction occurs in three waves (i(1), i(2), and i(3)) the height of which changes with pH. We proved that in wave i(1) H3SeO3+ is reduced, in i(2) H2SeO3, and in i(3) HSeO3- SeO32- is not reducible. All reductions involve a transfer of six electrons and yield selenides. Limiting currents are controlled by the rate of protonation. As proton donors, in addition to H3O+, the acid forms of the buffer present also act. Limiting currents increase markedly with increasing concentration of the buffer. Tenfold increase in buffer concentration can result in up to 200% increase in limiting current.