溴酸钾氧化二甲基黄动力学光度法测定食品中的痕量硒(Ⅳ)

Kinetic Spectrophotometric Determination of Trace Selenium(Ⅳ) Based on Discoloring of Dimethyl Yellow Oxidized by Potassium Bromate

基于0．004mol／L的HNO3介质中，在乳化剂OP存在时，痕量硒（Ⅳ）催化溴酸钾氧化二甲基黄的褪色反应，建立了测定痕量硒（Ⅳ）的催化光度法。方法检出限为0．015μg／L，线性范围为0～0．8μg／L，加标回收率为98．0％～102．5％，样品测定的相对标准偏差（RSD）为2．6％～7．2％。用于测定食品中的痕量硒（Ⅳ）时，结果满意。

Based on the catalytic effect of trace selenium （ Ⅳ） on discoloring reaction of dimethyl yellow with potassium bromate in 0. 004mol/L nitric acid solution and in the presence of OF emulsifier, a method for determination of trace selenium （Ⅳ） by kinetic spectrophotometry has been developed. The detection limit is 0. 015 μg/L and the linear range of determination is 0-0. 8μg/L for tin. The recoveries are 98.0-102. 5%, and the relative standard deviation （RSD） is 2.6%- 7.2%. Combined solvent extract separation, the method has been applied to the determination of trace selenium （Ⅳ） in foodstuffs samples with satisfactory results.