J. Technology and Education, Vol.17, No.2, pp.81-86, 2010
長岡技術科学大学 生物系 (〒940-2188 新潟県長岡市上富岡町1603-1)
* kuwataka@vos.nagaokaut.ac.jp
Electrochemical oxidation of nicotinamide adenine dinucleotide with a dihydroxybenzaldehyde-modified electrode
Takashi KUWAHARA, Syuya ABE, Mizuki KONDO, and Masato SHIMOMURA
Department of Bioengineering, Faculty of Engineering, Nagaoka University of Technology
1603-1, Kamitomioka-machi, Nagaoka 940-2188, Japan
(Received November 16, 2010; Accepted December 6, 2010)
The electrochemical oxidation of nicotineamide adenine dinucleotide (NADH) was investigated by use of a carbon fiber paper (CFP) electrode modified with 2,5-dihydroxybenzaldehyde (25Q). The modified CFP (25Q/CFP) was prepared by electrochemical polymerization of 25Q in an acetonitrile solution. 25Q/CFP gave a reversible redox wave with a mid-potential (formal potential) of +0.02 V vs. Ag/AgCl in a 0.10 M phosphate buffer (pH 7.0). Electrochemical oxidation of NADH was successfully accomplished with 25Q/CFP, and the oxidation current reached 0.25 mA/cm2 at +0.2 V vs. Ag/AgCl. The onset of oxidation of NADH was found at +0.01 V vs. Ag/AgCl, which corresponds to the mid-potential of 25Q/CFP at pH 7.0. The onset potential was 0.34 V lower than that observed with untreated CFP. The CFP electrodes modified with 3,4-dihydroxybenzaldehyde (34Q) and 2,3-dihydroxybenzaldehyde (23Q) were compared to 25Q/CFP with respect to the oxidation of NADH. The largest NADH oxidation current at +0.2 V was obtained with 23Q/CFP, and the current was 3.5 times as large as that with 25Q/CFP. However, the onset potential observed with 25Q/CFP for the oxidation of NADH was lower than that observed with 34Q/CFP and 23Q/CFP by 0.08 V.
Keywords: Dihydroxybenzaldehyde, NADH, Quinone, Electrochemical polymerization