Study on determination of micro amounts of iodine in water by catalytic potentiometric method using methyl violet electrode

A new catalytic potentiometric method for determining micro amounts of iodine has been developed.It is based on the catalytic effect of iodine ion on the oxidation of methyl violet by sodium periodate.Methyl violet electrode made by ourselves has been used for indicating the change of the concentration of methyl violet in the reaction system.The optimum experiment conditions for the determination was studied.The linear range of the determination for iodine is 20-280 ng/mL,and the correlation coefficient is 0.999 0.The detection limit for iodine is 6.0 ng/mL.The common existing ions do not interfere in the determination of iodine,showing the good selectivity of method.The method has been applied to the determination of iodine in lake water and tap water with the recovery of 98.04%-99.86%,and the relative standard deviation of 0.92%-1.47%.