Differential electrolytic potentiometry (DEP) was coupled with Flow injection analysis (FIA) technique for the determination of ascorbic acid in pharmaceutical preparations. Platinum electrodes were used as an indicating system to follow the oxidation of vitamin C with either potassium iodate, or potassium permanganate in an acidic medium. Univariate method was employed to optimize the variables such as the current density, the flow rate, the concentrations of the oxidants and the sulfuric acid. A current density of 40 μAcm
-2 and a flow rate of 25 μlsec
-1 were found to be optimum. The optimum concentrations of iodate and permanganate were 8.35 mM and 0.11 mM respectively. On using iodate as an oxidant the method showed a linear range of 12-130 μgml
-1, a detection limit of 9 μgml
-1 and R2 of 0.999. In case of permanganate a linear range of 18-36 μgml
-1, a detection limit of 11 μgml
-1 and an R2 of 0.996 were obtained. The procedure was applied successfully to the determination of vitamin C in commercial tablets. The results of this study were found to be statistically comparable with those obtained by official methods.
抄録全体を表示