协同增敏Fe(Ⅱ)-邻二氮菲阻抑动力学光度法测定食盐中痕量碘

Deter mination of trace amounts of iodine in edible salt by inhibition-spectrophotometry of iron(Ⅱ)-orthophenanthroline system

在硫酸介质中,痕量碘酸根离子对Fe(Ⅱ)-邻二氮菲体系的显色反应有明显的阻抑作用,据此建立阻抑动力学光度法测定微量碘的方法。研究了阻抑反应的动力学参数包括表面活性剂增敏、酸度、试剂用量、试剂加入顺序和时间等,确定了最优化的反应条件。方法的线性范围为0.05~2μg·m L^(-1),检测限为0.03μg·m L^(-1)。该方法操作简便、灵敏度高、选择性好,用于食盐中微量碘的测定,取得满意的结果。

A new inhibitory kinetic spectrophotometric method for the deter mination of trace amounts of iodine in edible salt was proposed.This method was based on the inhibitory effect of iodate on the oxidation of iron（ Ⅱ） by iodate in the presence of sulfuric acid.The effects of reaction parameters such as surface active agent,acidity,reagent consumption,reagent addition sequence and time were investigated and optimized.Under the optimum conditions,the calibration curve was linear in the range of 0. 05 ～ 2 μg·L^-1with the detection limit of 0. 03 μg·m L^-1.The developed method was simple,sensitive and selective,which was applied to the deter mination of trace level of iodine in edible salt with satisfactory results.