乙基紫共振瑞利散射法测定碘酸钾

Determination of Potassium Iodate by Resonance Rayleigh Scattering Method with Ethyl Violet

在磷酸介质中,碘酸钾与碘化钾反应生成I3-配阴离子,它可进一步与乙基紫形成离子缔合物,此时不仅能引起吸收光谱的变化,而且能导致共振瑞利散射(RRS)的显著增强并产生新的RRS光谱,其最大散射波长位于319nm.在一定条件下,其散射强度ΔI与碘酸钾浓度成正比,其线性范围在2·33×10-3～3·00μg·mL-1之间,方法具有极高的灵敏度,对碘酸钾的检出限为0·70ng·mL-1,也具有良好的选择性,可用于食盐中碘酸钾的直接测定.

In H3PO4 solution,potassium iodate reacts with potassium iodide to form I^-3, which further interacts with ethyl violet to form ion-association complexes. This results in significant enhancement of intensity of the resonance Rayleigh scattering （RRS） and the appearance of a new RRS spectrum. The maximum RRS peak is located at 319 nm,the intensity of RRS （△I） is directly proportional to the concentration of potassium iodate in the range of 2.33×10-3 —3.00μg·mL^-1 and the detection limit is 0. 7 ng·mL-1.The method has a good selectivity and can be applied to the determination of potassium iodate in table salt with satisfactory results.