APPLICATION OF ANODIC REDISOLUTION VOLTAMPEROMETRY FOR THE DETERMINATION OF ANTIMONIUM

Abstract

A voltammetric method was validated to determine the concentration of antimony in aqueous medium. The voltammetric technique of anodic redissolution was used, using a potentiostat. Chronoamperometry was applied at E = -1,2 V for 50 s. A linear sweep voltammetry was applied with potentials between Ei = -1,2 V and Ef = 0,5 V at a speed of 20 mV/s. This was carried out in 0,5 M H3 PO4 electrolytic solution, where an increase in the current intensity peak can be observed as a function of the concentration of the solutions evaluated at a potential of 84,96 mV. To validate the method, linearity, precision, limit of detection and limit of quantification were determined. Four concentrations of antimony were prepared in triplicate, in a range of 1, 5, 10, 15, 20 mg/L, respectively. A calibration curve of experimental concentration expressed as current intensity (I) vs theoretical concentration was constructed. The linearity was demonstrated starting from the coefficient of proportionality of 0,9979 with coefficient of variation (CV) of 18,2 %. The limit of detection and quantification had values of 1,041 mg/L and 1,718 mg/L respectively.