氢化物发生原子吸收法测定食物中硒

DETERMINATION OF SELENIUM IN FOODS BY HYDRIDE GENERATION-ATOMIC ABSORPTION SPECTROMETRY

本文介绍了一种用氢化物发生原子吸收法测定食物中硒的方法。本方法的最小检出量为2ng,重复测定的变异系数小于10％,加入到食物样品中无机硒的回收率为83％～112％。用本方法分析猪肝和甘蓝两种标准物质中的硒,测定值和标准值吻合。应用数理统计方法研究了样品前处理过程中被测成分硒的损失与污染。

A method for determination of seleninm in foods by hydride generation -atomic absorption spectrometry was described. Food samples were digested by heating with a mixture of nitric, perchloric, and sulfuric acids. After addition of 4ml of 6mol/L HC1, the digests were heated in a boiling water bath to reduce selenate to selenite. The hydride of selenium was evolved by reduction with 1% KBH4 from a system of 2mol/L HC1-1% K3Fe(CN)6 and then atomized in a laboratory-constructed electrically heated silica absorption tube. Absolute detection limit of the method was 2ng and the linear range was from 0 to 10 ng/mlSe. Recoveries of inorganic selenium added to a variety of foods ranged from 83% to 112%. Accuracies checked with standard materials of pig liver and brassica oleraca were within the certified values. The loss and pollution of selenium during the sample pretreatment were also studied.