碘酸钾-碘离子体系催化动力学电位法测定痕量铜

Catalytic Kinetic Potentiometry for Determination of Trace Copper by Using Potassium Iodate-iodide System

KIO3氧化 KI的反应为指示反应 ,用碘离子选择电极跟踪 I- ,建立了催化动力学测定铜的新方法 .在适宜条件下 ,该指示反应为一级反应 ,反应速度可用电位的变化 ΔE表示 .ΔE与铜浓度在 5～ 375 ng/m L 范围内呈线性关系 ,检出限为 1.6 ng/m L.水样的测定及回收试验均得到了满意结果 .

A new indicator reaction, the oxidation of iodide by potassium iodate,can be catalyzed by copper apparently. An iodide ion selective electrod was used for follow the process of the reaction in the experiment. Thus a new method was suggested for determining trace copper by catalytic kinetic potentiometry. It is found that the indicator reaction is a first order reaction at proper condition and the reaction rate can be expressed as the variation of potential (Δ E ).At a fixed time procedure,the Δ E is linearly related to the concentratoin of copper in the range of 5～375ng/mL. The detection limit of Cu 2+ is 1.6mg/mL. The method is applied to determine the trace copper in water sample with satisfactory results.