Electrocatalytic Response of Dopamine at a Metallothioneins Self-Assembled Gold Electrode

• DOI: 10.2116/analsci.18.635
• Publication Date: 2005-04-20T06:06:57Z
• Authors: Qian Wang; Nanqiang Li; Wenqing Wang
• Keywords: Dopamine; Hydrogen-Ion Concentration; 01 natural sciences; Catalysis; 0104 chemical sciences; Models, Chemical; Spectroscopy, Fourier Transform Infrared; Electric Impedance; Electrochemistry; Metallothionein; Gold; Electrodes; Oxidation-Reduction

The metallothioneins (MT) self-assembled monolayer modified gold electrode (MT/Au) is demonstrated to catalyze the electrochemical response of dopamine (DA) by cyclic voltammetry. A pair of well-defined redox waves was obtained and the calculated standard rate constant (k(s)) is 6.97 x 10(-3) cm s(-1) (20 degrees C) at the self-assembled electrode. The electrode reaction is a quasi-reversible process. The oxidation peak of DA can be used to determine the concentration of DA. The peak current and the concentration of DA follow a linear relationship in the range of 2.0 x 10(-5) M to 8.0 x 10(-4) M. The detection limit is 6.0 x 10-6 M. By ac impedance spectroscopy, the apparent electron transfer rate constant (k(app)) of Fe(CN)6(3-)/Fe(CN)6(4-) at the MT/Au electrode was obtained as 2.0 x 10(-5) cm s(-1). The MT/Au was characterized with grazing angle FT-IR spectroscopy and contact angle goniometry.