催化光度法测定痕量铅

Determination of Trace Lead by Catalytic Spectrophotometry

在活化剂Tween-20的存在下和六次甲基四胺-盐酸缓冲溶液(pH 5.0),痕量Pb(II)催化高碘酸钾氧化愈创木酚这一新的指示反应及其动力学参数,建立了催化动力学光度法测定痕量Pb(II)的新方法。该方法的线性范围为0～0.9μg/mL,检出限为9.9×10-3μg/mL,相对标准偏差(RSDs)为1.3%～3.9%,标准加入法的回收率为91.8%～108.2%,该方法具有快速、灵敏、简便等优点,应用于实际烟草样品中痕量铅的测定,结果与ICP-MS法相吻合,为检测烟草中痕量铅提供了新的技术手段。

A new catalytic kinetic spectrophotometric method for the determination of trace lead（II） was established based on the fact that Pb（II） could catalyze the indicating oxidation reaction of guaiacol by hexamethylenetetramine and hydrochloric acid medium at pH 5.0 and the kinetic conditions was investigated,when Tween-20 was used as the activator.The linear range of the determination was 0～0.9 μg/mL and detection limit was 9.9×10-3 μg/mL.The method had been applied to determine trace Pb（II） in tobacco with the RSDs of 1.3%～3.9% and recoveries of 91.8%～108.2% and the results coincided with the ICP-MS,could be used as a new method to detect Pb（II） in tobacco,which is fast,sensitive and simple.