ABSTRACT:
Differential pulse anodic stripping voltammetric analysis (DPASVA) of selenium(IV) using a gold electrode modified with O-Phenylenediamine-nafion (GEMO-PN) has been studied. Various parameters (electrolyte, deposition time, pulse duration, pulse amplitude, etc.) affecting the Se(IV) determination were examined. Selenium(IV) was determined in an aqueous HClO4 (0.2 M) medium of pH 0.22 at an accumulation potential of -350 mV (vs. Ag/AgCl) and an accumulation time of 200 s. Under the optimum conditions, liner calibration graph, Ip=f(CSe4+), was obtained in the concentration ranges of 5x10-8 M (3.948 ng/mL) to 1x10-6 M (78.96 ng/mL) with relative standard deviations (RSD) 3.8%, and the detection limit was 0.048 ng/mL. This method showed a good accumulation efficiency for selenium and good resistance to interferences from metal ions as well as those associated with selenium in pharmaceuticals. The results for the determination of Se4+ using (GEMO-PN) were more sensitive and accurate than that obtained using bare gold electrode; the sensitivity was increased about 2000 times.