固体汞电极平行催化伏安法测定痕量亚铁离子

研究固体汞电极线性扫描伏安法测定痕量亚铁离子(Fe2+)的分析方法。在pH值为5.2的醋酸-醋酸钠缓冲溶液中,亚硝基R盐(NRS)与Fe2+形成络合物,H2O2存在时,在固体汞电极上产生灵敏的还原峰,峰电位-1.3V。峰电流与Fe2+的浓度在5.6×10-7～2.0×10-4g/L范围内呈线性关系,检出限1.5×10-7g/L。NRS中的-NO在电极上得2e-还原为中间物质-NHOH。当溶液中存在H2O2时,H2O2可以迅速将其又氧化成-NO,从而形成灵敏的带吸附性质的平行催化体系。该方法灵敏度高,简便快捷,成本低廉,而且使用安全。

Parallel Catalytic Voltammetric Determination of Fe2+ by Using Solid Amalgam Electrode

The quantitative analysis of Fe2＋ by parallel catalytic voltammetric method with the aid of the solid mercury electrode was described in this paper.In acetate sodium acetate buffer（pH=5.2）,nitroso R salt（NRS） reacted with Fe2＋ to form a complex and a sensitive reductive peak was obtained at-1.3 V in the presence of H2O2.There was a linear relationship between peak current heights and Fe^2＋ concentration in the range of 5.6×10^-7～2.00×10^-4g/L,with a detect limit of 1.5×10^-7g/L.The influence of buffer solution,the concentration of nitroso R salt and hydrogen peroxide were tested.The mechanism of the parallel catalytic system was proposed.NRS in the complexes of Fe-NRS can be absorbed on the mercury electrode surface and the-NO of NRS was reduced by 2e-to form the intermediate of-NHOH.With the existing H2O2,-NHOH can be oxidized by H2O2 rapidly to reform-NO.Thus,a sensitive reduced current was obtained by the parallel catalytic system.The method had be applied to determine ion contents in water sample.It is low-cost,simple,rapid,accurate and safe.