Studies on the electrochemical behaviour of hydroquinone at L-cysteine self-assembled monolayers modified gold electrode

L-Cysteine is combined onto gold electrode to form a self-assembled monolayers modified electrode ( L-Cys/Au SAMs) by taking advantage of strong sulfur-gold interaction. ATR-FTIR, SEM, cyclic voltammetry ( CV) and impedance were used for the characterization of the film. It shows excellent stability upon voltametric scanning and a good voltametric response towards hydroquinone with the potential ranged from 0.8 to -0.2 V ( vs. SCE) in 0.5M HAc-NaAc buffer solution ( pH 4.8). The oxidation potential of hydroquinone on the modified electrode shifted negatively about 330 mV as compared with the bare gold electrode. The plot of catalytic current vs. its concentration has a good linear relation in the range of 2.0 x 10(-6) -2.0 x 10(-4)M with the correlation coefficient of 0.9986 and the detection limit of 4.0 x 10(-7) M by different pulse voltammetry (DPV). Mechanism for the electrocatalytical process has been studied.