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Voltammetric discrimination of mandelic acid enantiomers

Zor, Erhan, Saf, Ahmet O., Bingol, Haluk, Ersoz, Mustafa
Analytical biochemistry 2014 v.449 pp. 83-89
biosensors, dielectric spectroscopy, electrochemistry, enantiomers, gamma-globulins, glassy carbon electrode, graphene oxide, mandelic acid, oxidation, scanning electron microscopy
We report a novel electrochemical biosensor for direct discrimination of d- and l-mandelic acid (d- and l-MA) in aqueous medium. The glassy carbon electrode (GCE) surface was modified with reduced graphene oxide (rGO) and γ-globulin (GLOB). Electrochemical characterization of the modified electrodes was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The modified electrode surfaces were also characterized by scanning electron microscopy. Electrochemical response of the prepared electrode (GCE/rGO/GLOB) for discrimination of d- and l-MA enantiomers was investigated by cyclic voltammetry and was compared with bare GCE in the concentration range of 2 to 10mM. Whereas the bare GCE showed no electrochemical response for the MA enantiomers, the GCE/rGO/GLOB electrode exhibited direct and selective discrimination with different oxidation potential values of 1.47 and 1.71V and weak reduction peaks at potential values of −1.37 and −1.48V, respectively. In addition, electrochemical performance of the modified electrode was investigated in mixed solution of d- and l-MA. The results show that the produced electrode can be used as electrochemical chiral biosensor for MA.