Kinetic Determination of Traces of Iodide by Its Inhibitory Effect on the Oxidation of Gallocyanin by Bromate in Micellar Medium

Abstract

A new, simple and selective kinetic spectrophotometric method was developed for the determination of ultra trace amounts of iodide over the range of 0.1-100 ng/mL.The method is based on the inhibitory effect of iodide on the oxidation of gallocyanin by bromate in acidic and micellar medium. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of gallocyanin at 542 nm with a fixed-time 0.5-2.0 min from initiation of the reaction. The relative standard deviation of 1 and 40 ng/mL iodide was 2.3 and 1.9 %, respectively. The method was applied to the determination of iodide in water.