Distinguishing Three Halate Anions by Using a Ph Clock System

In this study, we report an electrochemical method for the identification of three halates (ClO3-, BrO3-, and IO3-) by using a pH clock system composed of HCHO-NaHSO3-Na2SO3. When equal amounts of analytes (ha-lates) are separately added to the clock system, the increase in the induction period for the clock system is observed to be IO3- > BrO3 - > ClO3-. Three halates are then distinguished from each other by such different perturbation effects. Furthermore, there is a linear relationship between the concentration of halates and the induction period in the range of 5.0 x 10-4-2.0 x 10-3 mol/L. The quantitative analysis for halates is then to be achieved. Finally, the perturbation mechanisms of the three halates on the pH clock system are explained in detail.