溴酸钾-碘离子体系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 by the Potassium Bromate-Iodide System

实验中发现NO-2 对KBrO3 氧化I-的反应有很强的催化作用。可用碘离子选择电极跟踪反应过程 ,由此建立了测定痕量NO-2 的新方法。在适宜条件下 ,该指示反应为一级反应 ,反应速度可用电位变化ΔE表示。当时间固定 ,ΔE与NO-2 浓度在 0～ 1 6× 10 -6mol/L范围内呈线性关系 ,检出限为 1 4× 10 -10 mol/L。该方法已用于肉类、蔬菜、粮食和血清中NO-2 的测定 ,得到了可靠结果。

A new catalytic Kinetic method was described for the determination of trace nitrite, based on its intensely catalytic effect on the oxidation of iodide by potassium bromate. The reaction process was followed potentiometrically by measuring the rate of variation of potential using a iodide ion selective electrode. At the suitable conditions, the indicator reaction is a first_order reaction and the reaction rate can be expressed as the variation of potential(Δ\%E\%) which is linear with the concentration of nitrite in the range of 0～1\^6×10\+\{-6\} mol/L at fixed_time procedure. The detection limit of nitrite is 1\^4×10\+\{-10\} mol/L. This method has been applied to determine the nitrite in meat, vegetable, grain and serum with satisfactory results.