催化动力学电位法测定痕量亚硝酸根

Catalytic Kinetic Potentiometry for the Determination of Trace Nitrite

基于稀硫酸介质中 ,亚硝酸根对溴酸钾氧化碘化钾有催化作用 ,用碘离子选择电极跟踪 I- ,建立了测定痕量亚硝酸根的催化动力学电位法。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 (△ E)表示。当时间固定时 ,△ E与亚硝酸根浓度在 0～ 0 .1 2 mg/L范围内呈线性关系 ,检出限为 2 .0 μg/L。该法用于水样中痕量亚硝酸根的测定 。

A catalytic kinetic potentiometry for determination of trace nitrite has been developed. The method is based on the oxidation of iodide by potassium bromate which can be catalyzed by nitrite in the solution of diluted H 2SO 4. The concentration of iodide is followed by iodide ion selective electrode. Under the suitable conditions,the indicator reaction is first order and the reaction rate can be expressed as the change of potential(△ E ). The △ E is linear with concentration of nitrite in the range of 0～0.12 mg/L at fixed time procedure. The detection limit of nitrite is 2.0 μg/L. This method has used to the determination of trace nitrite in water samples with satisfactory results.