基于在稀磷酸介质中,痕量碘离子对亚硝酸根催化溴酸钾氧化甲基红的的阻抑作用,提出了测定痕量碘离子的阻抑动力学分光光度分析的方法.测定碘离子的线性范围在0.66 mg·L-1以内,检出限(3Sb/K)为7.5×10-6g·L-1.用于海带及食盐中微量碘的测定,测定结果的相对标准偏差(n=6)在1.4%~2.2%之间,测得方法的回收率为99.7%~100.1%.

Based on the inhibition action of microamounts of iodide ion on the catalytic reaction of nitrite on oxidation of methyl red by potassium bromate in dil.H3PO4 medium,a new method of inhibition kinetic spectrophotometric determination of trace amounts of iodide was proposed.Linear relationship between values of ΔA (difference of absorbances of the inhibition reaction system and the catalytic reaction system) and concentration of iodide ion was kept in the range within 0.66 mg·L-1 of solution.Detection limit (3Sb/K) found was 7.5×10-6g·L-1.Samples of table salt and kelp were analyzed by the proposed method for contents of iodide,giving values of recovery and RSD′s (n=6) in the ranges of 99.7%-100.1% and 1.4%-2.2% respectively.