[Kinetic spectrophotometric determination of iodate in iodized salt samples]

A kinetic spectrophotometric method for the determination of iodate based on consecutive reactions was proposed. The method was based on the kinetic process of the analytes which react with starch-iodide in the presence of sodium chloride in sulfuric acid medium. It was found that the intermediate triiodide ion was produced in the consecutive reactions and the three peak wavelengths, 291, 354 and 585 nm, were obtained in the whole reaction process. And then the three peak wavelengths were chosen as the optimization conditions. In the reaction time of 180 s, the obtained linear calibration concentration ranges at the three peak wavelengths under the optimized conditions were 0.1-1.2, 0.05-1.2 and 0.1-1.2 microg x mL(-1), respectively, and the detection limits were 0.047, 0.027 and 0.048 microg x mL(-1), respectively. As there were the widest linear range and the lowest detection limit at the peak wavelength 354 nm, the wavelength was chosen for the quantitive ananlysis of iodate. At the same time, the method was successfully applied to the determination of iodate in iodized salt samples.