聚硫堇修饰微带金电极的性质及对NADH的催化氧化

Electrocatalysis of Poly-thionine Modified Microband Gold Electrode for Oxidation of Reduced Nicotinamide Adenine Dinucleotide

报道了硫堇在微带金电极上的电化学聚合过程，用红外光谱对聚硫堇进行了表征；研究了聚硫堇的电化学性质，发现聚硫堇在＋０．５～－０．７Ｖ（ｖｓ．ＳＣＥ）电位范围内有两对氧化还原峰，峰电位分别为：Ｅ＝－０．０３Ｖ、Ｅ＝０．０５Ｖ，Ｅ＝－０．２４Ｖ、Ｅ＝－０．１７Ｖ（ｖｓ．ＳＣＥ）。它们的式量电位Ｅ^（ｏ＇）随ｐＨ而变化，在弱酸性溶液中，Ｅ^（ｏ＇）／ｐＨ为－２９ｍＶ／ｐＨ（２５℃）；而在弱碱性溶液中则为－５６ｍＶ／ｐＨ。聚硫堇修饰微带金电极对ＮＡＤＨ的氧化具有催化作用，文中对电催化过程进行了探讨。

The electrocatalytic oxidation of NADH in phosphate buffer solution (pH=7.0)by poly-thionine modified microband gold electrode was investigated.The electrochemical polymerization of thionine in acetonitrile solution and the properties of the resulting films were studied.It was found that the addition of acids such as CF_3COOH to the medium markedly facilitates the film formation.The poly-thionine film was characterized by IR spectra.Two redox couple of poly-thionine in the potential range of-0.7─+0.5 V (vs.SCE)were observed,one of them possesses the monomer-type activity.The peak potentials are E =-0.03 V,E =0.05 V;E =-0.24 V and E =-0.17 V (vs.SCE,25℃). A slope of-29 mV/pH for the plot of E￣(o')vs. pH was observed in acidic solution,whereas in alkaline solution the slope was-56 mV/pH.