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以I_3~-—淀粉络合物为指示剂研究了Se(Ⅳ)对Cr(Ⅵ)—I~-氧化还原反应体系的诱导作用,并据此提出了一种测定痕量硒的动力学新方法;本法测定硒的线性范围为0～2.1μg/ml.方法检测限为7ng/ml Se(Ⅳ)。除Te(Ⅳ)、Fe(Ⅱ)和Sb(Ⅲ)外,其余离子具有较大允许共存量,可不经分离直接测定。用本法测定了铜矿标准物及污染土壤中的硒含量,结果满意。样品加标回收宰为95.8～97.9％,相对标准偏差RSD<2.9％。
The induction of Se (Ⅳ) on the Cr (Ⅵ) -I ~ - redox system was studied by using I_3 ~ - starch complex as an indicator, and a kinetic method for the determination of trace selenium The linear range of this method for the determination of selenium was 0 ~ 2.1 μg / ml. The detection limit was 7 ng / ml Se (Ⅳ). Except for Te (Ⅳ), Fe (Ⅱ) and Sb (Ⅲ), other ions have larger allowable coexistence, which can be directly determined without separation. The content of selenium in copper standard and contaminated soil was determined by this method and the result was satisfactory. Recoveries were 95.8-97.9% spiked with RSD <2.9%.