Effect of Tartaric Acid on the Electrochemical Behavior of K<sub>3</sub>[Fe(CN)<sub>6</sub>] on the Electrodes Coated with Cyclodextrin Modified Multi-Walled Carbon Nanotubes

Abstract

The effect of tartaric acid on the electrochemical behavior of K3[Fe(CN)6] was investigated on bare ITO electrodes, electrodes coated with multi-walled carbon nanotubes possessing carboxyl groups (MWNT-COOHs), and electrodes coated with cyclodextrin modified multi-walled carbon nanotubes (MWNT-CDs), respectively. It is found that the molecular chirality of tartaric acid can hardly influence the electrochemical behavior of K3[Fe(CN)6] on bare ITO electrodes. When the electrodes coated with MWNT-COOHs are used, the effect of the molecular chirality becomes distinguish. In the case of the electrodes coated with MWNT-CDs, the enhanced chiral discrimination between D-tartaric acid (D-TA) and L-tartaric acid (L-TA) can be observed. The control step in the electrochemical reaction of K3[Fe(CN)6] on the electrodes coated with MWNT-CDs is deduced to be different when D-TA or L-TA is introduced into the solution, respectively. Therefore, the enhanced chiral discrimination on the electrodes coated with MWNT-CDs is probably due to the change of the control step in the electrochemical reaction of K3[Fe(CN)6] caused by the chiral recognition of cyclodextrin moieties to D-TA and L-TA.