甲基红褪色光度法测定数量溴酸根离子

Photometric Determination of Microamounts of BrO_3 by Oxidation-decoloration of Methyl Red

研究了盐酸介质中 ,在氯化纳的催化作用下 ,溴酸根离子氧化甲基红褪色的最佳条件 .吸收波长为 5 18nm .表观摩尔吸光系数为 7.2×10 4 L· m ol- 1 · cm- 1 ,溴酸根离子在 3.0～ 18μg/2 5 m L范围内符合比尔定律 .方法用于化学试剂中微量溴酸根的测定 ,结果令人满意 .

The optimum conditions for oxidation of methyl red in a hydrochloric acid medium by a BrO - 3 with sodium chlorid as the catalyst were studied.The maximum absorption wavelength of methyl red lies at 518nm with a molar absorptivity of 7.2×10 4L·mol -1 ·cm -1 .A decrease of absorbency of methyl red results from its oxidation by BrO 3,and a linear relationship is established between the decrease of absorbency and BrO - 3 concentration of 3.0-18g/25ml.This method is applied to the determination of micro amounts of BrO - 3 in chemical reagents with satisfactory results.