Electrochemical properties of L-cysteine self-assembled membrane modified gold electrode

Electrochemical quartz crystal microbalance and cyclic voltammetry were employed for studying the formation mechanism and electrochemical properties of the self-assembled membrane formed on the surface of the gold electrode. Experimental results show that specific interaction exists between L-cysteine and the gold electrode surface, additionally, the L-cysteine molecular pairs were formed due to the existence of electrostatic attraction and hydrogen bond between themselves in the solution with the PH around isoelectric point. Consequently, an L-cysteine self-assembled bilayer could be formed on the gold electrode surface. A pair of stable redox peaks were observed with the self-assembled bilayer modified gold electrode when potential scanning in 0.2 mol (.) L-1 HAc-NaAc buffer solution in the range of -0.2 similar to 0.5 V ( vs SCE). It was also found that the modified electrode has an obvious electrocatalytic effect on the electrooxidation of ascorbic acid.