甲基红法测定面粉中溴酸盐的含量

Determination of Bromate Content in Wheat Flour by Methyl Red Method

采用分光光度法，利用甲基红在酸性溴酸根溶液中的褪色反应，测定溶液中微量溴酸根的含量。研究了在氯化钠的催化条件下，盐酸介质中溴酸根离子的强氧化性质使甲基红褪色的最佳条件。结果表明：在吸收波长512nm处，表观摩尔吸收系数是2．06×103L·mol^-1．cm^-1时，在0．05～0．8μg/mL范围内，溴酸根离子吸收符合比尔定律，其最低检出限为0．08μg／g。该方法可快速、准确地测定面粉中溴酸根离子的含量。

Bromate content is determined in acid solution by spectrophotometric. It was based on the methyl red by potassium bromate in a dilute acidic solution. The optimum conditions for oxidation of methylred in ahydrochloric acidmedium by a BrO3^3- with sodium chloride as the catalyst were studied. The results shows that the maximum absorption wavelength lies at 512nm with a molar absorption of 2.06×10^3L·mol^-1.cm^-1. The absorbency of BrO3^3- is fitted Beer＇s law in 0.051-0.8 μ g/mL. The bromate content in wheat flour is quickly determined.