将蛋黄卵磷脂(egg-PC)和铁卟啉混合,浇筑到氧化铟锡玻璃(ITO)表面,实现了铁卟啉的直接电化学.结果表明,循环伏安图上出现了铁卟啉的一对峰形良好、对称的氧化还原峰.通过计算可以得到电活性铁卟啉的表面覆盖度为Γ=3.25×10-12 mol/cm2.随着磷酸盐缓冲溶液pH值从4.0升高到9.0,铁卟啉的式电位E°’线性负移,斜率为-43.7 mV/pH.综合考虑,在pH 4.0溶液中对H202检测,线性检测范围为10~ 200 μmol/L,检出限为5μmol/L.此修饰电极对H2 02具有良好的电催化活性,基于此研制出无媒介体的H2O2传感器.
The mixture of egg-phosphatidylcholine (PC) vesicles and hemin was casted onto indium-tin oxide glass (ITO) electrode. The hemin showed a direct electrochemical behavior on the modified electrode. A well- defined pair of redox peaks was obtained from the cyclic vohammograms at the mixture of hemin and egg-PC modified ITO electrode. The average value of the surface coverage of electroactive hemin, F, was equal to 3.25×10-12 mol/cm2. The formal potential (E0) of hemin in the lipid film was linearly varied with the pH of phosphate buffer solution in the range from 4.0 to 9.0 with a slope of 43.7 mV/pH. The pH value of buffer solution for measuring hydrogen peroxide was decided to be 4. O. The linear range of our biosensor was from 10 μmol/L to 200 μmol/L with a detection limit of 5μmoL/L. The modified electrode exhibited a good catalytic activity towards hydrogen peroxide. Therefore a third generation biosensor was developed.