二苯硫腙还原法测定痕量IO_3^-

Determination of trace IO_3^-by dithizone reduction

在含 IO_3^-的0. 5～11mol/L 盐酸溶液中,用10毫升二苯硫腙一四氢化碳溶液进行萃取时,IO_3^-能氧化二苯硫腙使其在有机相中的绿色减退。借测定反应前后有机相中二苯硫腙吸光度(620nm)的改变,建立了一个测定痕量 IO_3^-的新方法。方法的灵敏摩尔吸光系数ε=1. 7×10~5L.mol^(-1) .cm^(-1) ,最低检出限为1. 75×10^(-8) g.ml^(-1) IO_3^-,线性范围0. 175～6. 15μgIO_3^-/10mol 用于测定了 KNO_3样品中的 IO_3^-的含量,取得了满意的结果。

IO_3^-which is contained in 0. 5～lmol/L HCl solution extracted with dithizone in carbon tetrachloride.IO_3^-can oxidize dithizone So that the green color of dithizone in the organic phase will fade.By determining the changes of absorbance(620nm)of dithizone in the organic phase before and after reactions,a new method for the determination trace IO_3^-is developed.Sensitivity molar absorptivity of the method is 1. 7×10~5L·moL^(-1) ·cm^(-1) .The detection limit is 1. 75×10^(-8) g·mL^(-1) IO_3^-and the linear range is 0. 175～6. 15μg/10mL IO_3^-. The method has been applied to determination of IO_3^-in KNO_3. The results are satisfactory.