诱导动力学光度法测定痕量硒—Se(Ⅳ)—Cr(Ⅵ)—Ⅰ^-—淀粉体系

Kinetic Spectrophotometric Determination of Trace Selenium(Ⅳ)Se(Ⅳ)-Cr(Ⅵ)-I^--Starch System

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％。

A new kinetic spectrophotometric method for determination of trace seierium has been proposed based on its inductive effect on the chromium(Ⅵ) -iodide reaction. The calibration graph is linear for 0-2 lugiml Se(Ⅳ). Most foreign iors,except for Te(Ⅳ) ,Fe(Ⅱ) and Sb(Ⅱ) ,do not interfere with the determination. Selenium amounts in copper ore standard and a polluted soil had been determined,and the results are satisfactory.