甲基紫电极催化电位法测定水中微量碘的研究

基于在柠檬酸缓冲溶液中,碘离子催化高碘酸钠氧化甲基紫的反应,用自制的甲基紫离子选择性电极跟踪反应过程中甲基紫的浓度变化,研究了催化电位法测定碘的方法。结果表明,在选择的实验条件下,该方法测定碘离子的线性范围为20~280 ng/mL,相关系数为0.999 0,检出限为6.0 ng/mL,大多数常见离子不干扰测定。该方法用于管网水和天然水中微量碘的测定,样品回收率为98.04%~99.86%,相对标准偏差为0.92%~1.47%。

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%.