催化动力学极谱法测定痕量钼

Catalytic Kinetic Polarographic Determination of Trace Amounts of Molybdenum

在稀Ｈ２ＳＯ４介质中，钼（Ⅵ）对硫酸联氨还原乙基橙的反应有强烈的催化作用．而在０．０３ｍｏｌ／ＬＨ２ＳＯ４－０．３０ｍｏｌ／ＬＮＨ３支持电解质中，乙基橙产生一灵敏的极谱吸附波，峰电位为－０．５２Ｖ，以此作为监测催化反应过程中乙基橙浓度的变化，建立了催化动力学极谱法测定痕量钼的新体系，方法线性范围为２０－３００ｎｇ／ｍＬ，检出限为３．５４ｎｇ／ｍＬ．方法应用于尿中钼的测定。

This method is based on the catalytic effect of Mo(Ⅵ) on the redox reaction between ethyl orange and hydrazine sulfate in sulphuric acid medium at 100℃, and in 0.03mol/L H 2SO 4-0.30mol/L NH 3 H 2O supporting electrolyte, ethyl orange exhibits a sensitive polarographic wave at -0.52V (Vs.SCE). The change in ethyl oragne concentration is traced by polarography. The detection limit and the linear range of Mo(Ⅵ) are 3.54ng/mL and 20￣200ng/mL respectively. This new catalytic method has been applied to determining molybdenum in urine, with satisfactory results.