硫代硫酸钠滴定法测定市售食盐中的碘含量

Gauging the Amount of Iodine in Salt on Sale by the Way of Na_2S_2O_3 Titration

市售加碘盐中的碘素主要以IO-3 的形式存在 ,而IO-3 在酸性介质中能被I-还原成I2 ,生成的I2 再用Na2 S2 O3 标准溶液滴定 ,以淀粉为指示剂 ,滴定至溶液的蓝色刚好消失为终点 ,从而求得加碘盐中的碘含量 .

The iodine element in the salt with iodine on sale is in the existence of IO - 3; however, IO - 3 can be reduced into I 2 by I - in acid medium. The produced I 2 can be titrated by Na 2S 2O 3 standard titrant, with starch as indicator, titrating until the blue color in the solution disappears, then the amount of iodine in the salt with ioeine is obtained.