A simple spectrophotometric method for determination of antimony(III) with N-bromosuccinimide and methyl orange

In this study, a simple and sensitive spectrophotometric method for the determination of antimony(III) is described. It is based on the oxidation of antimony(III) with slight excess of N-bromosuccinimide (NBS) in acidic medium and the unconsumed (NBS) is determined with methyl orange (λ max 500 nm). Beer's law is obeyed over the concentration range of 0.4―2.8 μg/ml for antimony(III). The molar absorptivity and Sandell's sensitivity were found to be 3.43 x 10 4 L mol ―1 cm ―1 and 0.0035 μg cm ―2 respectively. The method has been successfully applied for the determination of Sb III in water, soil and biological samples.