镍(Ⅱ)与5-NO_2-PADAT络合吸附波的研究

STUDY ON THE ADSORPTIVE POLAROGRAPHIC WAVE OF THE COMPLEXFORMED BETWEEN NICKEL(Ⅱ) AND 5-(5′-NITRO-2′-PYRIDYLAZO)-2,4-DIMETHYLAMINO TOLUENE

镍（Ⅱ）-5-[2-（硝基吡啶偶氮）]-2，4-二甲氨基甲苯络合物在pH7．0的克拉克（Clarklubs）缓冲液中有较灵敏的极谱波，其峰电位Ep为-720mV（vs．SCE），镍浓度在0．01～2．5μg·L^-1。范围内与峰电流I′p呈线性关系，检出限为7．8ng·L^-1。经多种电化学方法证明该波为络合物吸附波，其电极过程为不可逆过程，电子转移数为2。试验了多种离子对峰电流I′p的影响，所拟方法已用于铝合金中镍的测定。

In a Clark-Lubs buffer medium of pH 7, 0, a coordination complex was formed between Ni（ Ⅱ ） ion and 5-（5＇-nitro-2r-pyridylazo）-2,4-dimethylamino toluene, and a sensitive adsorptive polarographic wave produced by this complex was observed with its peak potential （Ep） at -720 mV （vs, SCE）, Linear relationship between the peak current （Ip） and the concentration of Ni was obtained in the range of 0. 01-2, 5μg of Ni（ Ⅱ） per liter of the solution, with a detection limit of 7. 8 ng · L^-1. It was proved by several electrochemical methods, that the polarographic wave is a complex-adsorptive wave, and the electrode process is a irreversible process, involving an electron-transfer number of 2, Interference tests of more than 20 anions and cations commonly co-existed were performed and selectivity of the proposed method evaluated. The method has been applied to the analysis of aluminum alloy.