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化学学报
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化学学报 ›› 1990, Vol. 48 ›› Issue (1): 33-37. 上一篇    下一篇

研究论文

二氢辅酶的电催化氧化: I: α-萘甲酰尼罗蓝修饰电极性能研究

吴辉煌;蚁良东;周绍民   

  1. 厦门大学物理化学研究所
  • 发布日期:1990-01-15

Electrocatalytic oxidation of dihydrocoenzymes: I: Properties of α -naphthoyl nile blue modified electrodes

WU HUIHUANG;YI LIANGDONG;ZHOU SHAOMIN   

  • Published:1990-01-15

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465

新的电子传递中间体α-萘甲酰尼罗蓝(NNB)能强烈吸附在石墨上以构成修饰电极。在-0.5V至+0.6V(vs. SCE)电位区内, 固定化的NNB表观出相当可逆的氧化还原行为, 总反应中有2个电子和2个质子参加。在pH7.0缓冲溶液中其表面标准电位E°'为-170mV, 表观电子传递常数kg为3s^-^1。NNB对还原辅酶NADH的电化学氧化有明显催化作用, 可使氧化过电位降低550mV。NADH的电催化遵循EC机理, 催化反应步骤为速度决定步骤, 其速度常数为3×10^3dm^3.mol^-^1.s^-^1。NNB在中性和弱碱性介质中的稳定性优于其它电子传递中间体, 是有前途的电催化剂。

关键词: 稳定性, 氧化还原反应, 脱氢酶, 核苷二磷酸, 圆盘电极, 化学修饰电极, 电催化, 催化氧化, 电荷转移, 萘甲酸 P

a-Naphthoyl Nile blue (NNB) is a new electron-transfer mediator. It can be strongly adsorbed on graphite to make modified electrodes. The immobilized NNB exhibits relatively reversible redox behavior in the potential region from -0.5 to +0.6V (vs. SCE), 2 electrons and 2 protons taking part in the overall reaction. In pH 7.0 buffer solution, the surface standard potential E0' is -170 mV, and apparent electron-transfer rate constant ks is 3 s-1. NNB-modified electrodes show significant catalytic effects on electrochem. oxidation of dihydrocoenzyme NADH, making oxidation overpotential decrease by 550 mV. The electrocatalytic oxidation of NADH obeys EC mechanism, where the catalytic reaction is the rate-detg. step with a rate constant of 3 ?103 dm3/mol/s. In neutral and weakly basic solns., NNB is more stable than the other mediators; hence, it appears to be promising for practical applications.

Key words: STABILITY, OXIDATION REDUCTION REACTION, DEHYDROGENASE, NUCLEOSIDE DIPHOSPHATE, DISK ELECTRODES, CHEMICAL MODIFIED ELECTRODE, ELECTRO-CATALYSIS, CATALYTIC OXIDATION, CHARGE TRANSFER, NAPHTHALENECARBOXYLIC ACID P

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