结晶紫选择电极的制备及催化电位法测定碘的研究

Study on Determination of Iodine by Catalytically Potentiometric Method Using Crystal Violet Selective Electrode

根据磷酸介质中碘离子 ( I-)催化高碘酸钠氧化结晶紫的氧化还原反应 ,应用自制的结晶紫选择电极跟踪反应中结晶紫的浓度变化 ,对催化电位法测定碘进行了研究。测定碘离子的线性范围为 0 .2 0～ 5.5μg/ 2 5m L,方法检出限为 4 .1× 1 0 -9g/ m L。该方法应用于测定食盐和饮用水中碘含量 ,RSD<4 .1 %( n=6 ) ,平均回收率为 95.1 %。

A new catalytic potentiometric method for the determination of iodine was developed,based on the ability of iodide ion to catalyze.The redox reaction of crystal violet with sodium periodate in a phosphoric acid solution.A crystal violet ion selective electrode was used to indicate the change of the concentration of crystal violet in the reaction solution.This method can be operated conveniently.It showed high sensitivity and good selectivity,and had a linear relation within the range of 0.20～5 5 μg/25mL of I - and a detection limit of 4.1×10 -9 g/mL of I -.This method was used to determine iodine in table salt and drinking water samples with satisfactory results.The relative standard deviration (RSD) is less than 4.1% and the average recovery is 95.1% .