无机硒测定过程中的盐效应及其解决方法

Salt Effect on the Determination of Inorganic Selenium in Nature Water and Its Modified Method

在无机硒的测定过程中 ,Se(VI)还原为 Se(IV)的过程中存在严重的基质效应 ,本文采用加入浓的Na Cl溶液来消除基质效应 ,取得较好结果。方法的检出限为 0 .0 9nmol/ L,对 Se(VI)含量为 0 .89nmol/ L和 3.42 nmol/ L的样品分析精密度为 5.4%和 3.3% ,回收率在 95%～ 1 0 5%范围内变动。在不同介质中工作曲线斜率的变动范围 <5%。

It is observed that the salt content of nature wa te r has a profound influence on the determination of inorganic selenium when Se(VI ) is reducted to Se(IV). But it is found when the salinity is greater than 5, th e rate of reduction becomes constant after five minutes. Thus the interference o f salinity in the determination of inorganic selenium can be eliminated by addin g 1mL of NaCl(20%) to 15mL of water sample. The recovery of the modified method is 95%～105% with a relative standard deviation of 5.4% and 3.3% for sample s with 0.89nmol/L and 3.42nmol/L of Se (VI) respectively.