Based on catalysis of I-on the decolor reaction between potassium bromate and indigo carmine in the acid medium,and combined with flow injection analysis,a new flow-injection catalytic kinetic spectrophotometric method was found for determination of iodide in sample.The experimental results show that the determination is carried out at temperature of 80℃ and the concentration of H2SO4,KBrO3,and indigo carmine is 1.2 mol/L,1.8×10-2 mol/L and 1.0×10-4 mol/L respectively,the linear range for the method is 0.50～1.8 mg/L.The detection limit is 0.0022 mg/L.The relative standard deviation is 1.92%.The proposed method was applied to the determination of iodide in troche successfully.The recovery was between 99.2% and 103.6%.
