CATALYTIC-KINETIC-PHOTOMETRIC DETERMINATION OF TRACE AMOUNTS OF BISMUTH WITH DIBROMO-NITRO-ARSENAZO

It is found that the oxidation reaction between arsenazo DBN and KIO 4 is remarkably catalyzed by trace amounts of bismuth(Ⅲ) in a diluted H 2SO 4 solution. Based on this phenomenon, a photometric method for the determination of trace amounts of bismuth in tin base alloy and water is proposed. The detection limit is found to be 2.4×10 -9 g·ml -1 . A linear relationship between Δ A and concentration of bismuth in the range 0~7μg per 25ml of solution is obtained.