甲基橙氧化褪色光度法测定食盐中碘酸钾的改进

Improvement on the Method for Determination of Potassium Iodate in Salt by Oxidation Fading of Methyl Orange Spectrophotometry

在盐酸介质中,碘酸钾对甲基橙溶液有较好的氧化褪色作用,褪色程度与碘酸钾含量成正比关系。溶液的最大吸收波长为507nm,碘酸钾浓度在0~2.0μg/mL范围内与吸光度呈良好的线性关系,线性回归方程为△A=0.403c+0.0059,相关系数r=0.9995。用此法测定食盐中碘酸钾的含量,相对标准偏差(n=10)为3.25%,加标平均回收率(n=10)为102.5%。

In hydrochloric acid medium,potassium iodate has better oxidation fading effect on methyl orange solution,the degree of fading is proportional to the content of potassium iodate, the maximum absorption wavelength of solution is 507 nm, the concentration of potassium iodate is within 0 - 2. 0μg/mL, which has a good linear relationship with absorbance, the linear regression equation is △A=0. 403c＋ 0.0059,the correlation coefficient is r=0. 9995. The method has been used for the determination of the content of potassium iodate in salt. The relative standard deviation （n= 10） is 3.255, and the average adding standard recovery rate is 102.5% （n= 10）.