Stereoselectivity of tyrosine enantiomers in electrochemical redox reactions on gold matrices

Electrochemical reduction of tyrosine (Tyr) enantiomers on gold matrices in chlorhydric acid (HCl) solutions (0.01 M, pH 2.00) was performed. The characteristics of the Tyr reductive product adsorbed onto the electrode surface were studied using cycle voltammetry (CV). A significant redox peak of Tyr was observed from 0.70 to 1.60 V potential ranges. The compared investigation about electrocatalytic ability of Tyr enantiomers used gold matrices (bare gold electrode and electrodepositive gold nanoparticles modified glassy carbon electrode (AuNPs-GCE)). The Scanning Electron Microscope (SEM) images have been utilized to discuss the surface morphous. And the redox degree of l-Tyr on gold matrices was obviously much larger than that of d-Tyr. The mechanism for stereoselectivity in redox reactions of Tyr enantiomers on gold matrices had been analyzed. In addition, the AuNPs-GCE was used to determine Tyr enantiomers. Both l-Tyr and d-Tyr presented a sensitivity of 1.30 μM (S/N = 3), with two linear ranges from 4.00 μM up to 1.00 mM. This method proposed the possibility of using a nanostructured surface to discriminate and determine the chiral molecules in bio-electroanalytical application.