Chiral electrochemical sensing for tyrosine enantiomers on glassy carbon electrode modified with cysteic acid

A chiral electrochemical sensor has been prepared via cysteic acid modified glassy carbon (CyA-GC) electrode to discriminate tyrosine (Tyr) enantiomers . Sweep cycles of CyA-GC in modification process and pH of solution were investigated to obtain optimum experimental conditions. Electrochemical impedance spectroscopy was employed to characterize the electrical conductivity of the modified electrode . For the first time, different oxidation peak potentials ( E p ) of l - and d -Tyr were observed in the differential pulse voltammograms obtained in the solution containing l - or d -Tyr. Further study showed that only one peak appeared in mixture solution containing l - and d -Tyr and E p of that peak shifted positively and linearly with an increasing percentage of l -isomer of Tyr racemic mixture.