锇-聚乙烯吲哚配合物修饰电极对肾上腺素的电催化氧化

Electrocatalysis of Osmium Poly-vinylindole Complex Modified Glassy Carbon Electrodes to Epinephrine Oxidation

研究了配位聚合物锇 -聚乙烯吲哚 [Os( bpy) 2 ( PVI) 1 0 Cl]Cl和 Nafion双层膜修饰玻碳电极的电化学特性 ,该膜对肾上腺素 ( EP)的电化学氧化有催化作用 ,在通常的生理条件下 ( p H7.0 ) ,催化电流与 EP浓度在1 .0× 1 0 - 6～ 8.6× 1 0 - 5 mol/L范围内呈良好的线性关系 ,相关系数为 0 .9987.Nafion膜排除了抗坏血酸( AA)的干扰 ,表现出较高的灵敏度、选择性及良好的稳定性 .该电极可在 +2 50 m V下进行 EP的安培法测定 .用旋转圆盘电极对电催化过程的动力学进行了研究 ,催化速率常数 kch为 3 .53× 1 0 3mol- 1 · L· s- 1 .在较高 EP浓度下 ,催化电流与浓度的关系表现出 Michaelis-Menten型响应 ,Michaelis-Menten常数 Km 为1 .4 7mmol/L.

The electrocatalytic characteristics of osmium complex polymer [Os(bpy) 2(PVI) 10 Cl]Cl· (Os-PVI 10 ) and Nafion dual-layer membrane modified glassy carbon electrodes were studied. The modified electrodes show an excellent electrocatalytical activity for the oxidation of epinephrine(EP). Under the normal physiological condition, the catalytic current of EP vs. its concentration has a good linear relation in the range of 10×10 -6 —84×10 -5 mol/L with the correlation coefficient of 0998 7. Nafion membrane makes the modified electrodes eliminate efficiently the interference of ascorbic acid(AA). The modified electrodes exhibited a good reproducibility, sensitivity, and stability. The amperometric determination of EP concentration can be performed at +250 mV. The kinetic research was performed with a rotating disk electrode, and the electrocatalytical rate constant k ch was evaluated to be 353×103 mol -1 ·L·s -1 . At a high EP concentration, the relationship between the catalytic current and its concentration exhibits a Michaelis-Menten kinetic mechanism for the electrocatalytical process, and the constant K m is about 147 mmol/L.