血红蛋白在碳纳米管修饰碳糊电极上的直接电化学行为

利用吸附法将血红蛋白(Hb)固定在碳纳米管修饰碳糊电极表面,制成稳定的固载Hb碳纳米管修饰电极,研究了Hb在碳纳米管修饰电极上的直接电化学行为.固载Hb的碳纳米管修饰电极在pH=7.0的PBS（磷酸盐缓冲溶液）中有一对相当可逆的循环伏安氧化还原峰,为Hb血红素辅基Fe(Ⅲ)/Fe(Ⅱ)电对的特征峰.式电位为－0.160 V(vs SCE),随扫描速度变化很小.电子转移数为1.021,近似为一个辅基发生电子转移.Hb在碳纳米管修饰电极表面的电子转移常数为0.0816 s－1,远大于亚甲蓝作媒介体时Hb的电子转移反应速率常数.应用于过氧化氢、三氯乙酸和硝基苯等的电催化还原,固定在碳纳米管修饰碳糊电极的血红蛋白表现出稳定且较高的催化活性.

Direct Electrochemistry of Hemoglobin Immobilized on Carbon Paste Electrode Modified by Carbon Nanotubes

Direct electrochemical behaviors of Hemoglobin(Hb) adsorbed on carbon paste electrode modified by carbon nano-tubes(CNTs) were investigated. Hb-CNT-modified electrode showed a pair of well-defined and nearly reversible cyclic voltammetric peaks for HbhemeFe(Ⅲ)/Fe(Ⅱ) redox couple in phosphate buffered saline solution(pH=7.0).The formal potential (E01) was －0.160 V (vs SCE),which was almost independent of the scan rate. The number of electron transferred (n) was 1.021,suggesting about an electron transfer between the heme group of Hb and the electrode. The average apparent heterogeneous electron transfer rate constant (ks) obtained by fitting CV data for Hb on CNT-modified electrode was 0.0816 s－1,greater than the value obtained from the same method for Hb with methylene blue as mediators. Hb-CNT-modified electrode showed a stable and significant catalytic activity for the electrochemical reduction of hydrogen peroxide, trichloroacetic acid and nitrobenzene.