Tl(Ⅰ)-Cr(Ⅵ)-I^--淀粉体系催化光度法测定铊的研究

Studies on the Determination of Thallium with Catalytic Spectrophotometry

依据Tl(Ⅰ)对Cr(Ⅵ)-I^-淀粉氧化还原反应体系在微酸性条件下的诱导作用。提出了一种测定痕量铊的动力学新方法;除Fe(Ⅱ),V(Ⅳ),Ce(Ⅲ),Se(Ⅳ)等少数离子干扰测定外,其余常见离子均具有较大的允许量。本法线性范围为0～2.4μg/mL T1(Ⅰ),检测限为1.0ng/mL T1(Ⅰ)。多次样品加标回收率在96～97.5%之间,相对标准偏差小于1.6%,分析结果令人满意。

A Kinetic spectrophotometric method with high sensitivity for the determination of trace thallium has been proposed based on the inductive effect of thallium upon the Cr (Ⅵ)-I^--starch redox reaction. The calibration curve is linear for 0～2.4μg/mL of T1(Ⅰ). The detection limit is 1.0ng/mL. Fe(Ⅰ),V(Ⅳ),Se(Ⅳ)and Ce (Ⅲ) interfere with the determination. The recovery rate for thallium is better than 96%, and the RSD is 2.2%(n=6) for determination of 0.80μg/mL thallium. The method has been used for the determination of thallium in soils and the results are satisfactory.