Electrochemical behavior of sodium cholate and deoxycholate on an electrode modified with multi-walled carbon nanotubes (MWNTs) linked up with cyclodextrin

The electrochemical behavior of sodium cholate (CA) and deoxycholate (DCA) was investigated on ITO electrodes coated with β-cyclodextrin (β-CD) modified multi-walled carbon nanotubes (MWNTs) in aqueous solution. β-CD modified MWNTs (MWNT–CDs) showed electrocatalytic effect on the reduction of CA, while electrochemical response of DCA was not observed. To further understand the mechanism of the electrochemical process, the electrochemical behavior of CA and DCA on bare ITO electrode and the electrode modified with MWNTs possessing carboxyl groups (MWNT–COOHs) was also discussed. The results indicate that the electrochemical response of CA can be improved through the use of carbon nanotubes. The introduction of cyclodextrin moieties enhances the selectivity of the electrodes to CA and DCA.