Analytical application of acidic victoria blue 4R mixture with KBrO₃ for the kinetic determination of traces of antimony(III) by spectrophotometry

Abstract

The present paper describes a simple, selective and sensitive kinetic method for the determination of trace amounts of Sb(III) in the presence of Sb(V) based on its inhibition effect on the redox reaction between bromate and Victoria blue 4R (V.B. 4-R) in hydrochloric acid media. The reaction was followed spectrophotometrically by measuring the decrease in the absorbance of V.B. 4-R at 596.3 nm. Optimum operating conditions regarding reagent concentrations were established. The optimized conditions yielded a theoretical detection limit of 1.30·10‒8 g cm–3 Sb(III) based on the 3S0 criterion. The method allows the determination of Sb(III) in the range of 5·10‒8 ‒ 1.1·10‒6 g cm–3. The effects of certain foreign ions the reaction rate were determined for an assessment of the selectivity of the method. The kinetic parameters of the reaction were reported, and the rate equations were suggested. The results were validated statistically and through recovery studies. The proposed method has been successfully applied to the determination of Sb(III) in various model and real samples.