Spectrophotometric determination of bismuth(III and V) in water after ion-pair liquid–liquid extraction using tetramethylammonium cation as counter ion

Abstract

A simple extractive spectrophotometric method for the determination of bismuth has been developed. It is based upon oxidation of bismuth(III) to bismuthate with potassium periodate at pH 7–8. The resulting species is then extracted with tetramethylammonium iodide in chloroform followed by direct spectrophotometric measurement at 513 nm. The optimum concentration range evaluated by Ringbom’s method was found to be 0.05–10 mg l-1. The molar absorptivity and Sandell’s sensitivity for the formed ion-pair at 513 nm have been found to be 4.2×104 mol-1 cm-1 and 0.09 μg/cm2, respectively.