Electrocatalytic Oxidation of Venlafaxine at a Multiwall Carbon Nanotubes-Ionic Liquid Gel Modified Glassy Carbon Electrode and Its Electrochemical Determination

摘要

The electrocatalytic oxidation of venlafaxine (VEN) was investigated at a glassy carbonelectrode (GCE), the modified electrode by a gel containing multiwall carbon nanotubes (MWCNTs) anda room-temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophate (BMIMPF6) in0.10 mol L−1 phosphate buffer solution (PBS, pH 6.8). It was found that an irreversible anodic oxidationpeak of VEN with the peak potential (Epa) as 0.780 V appeared at MWCNTs-RTIL/GCE. The electrodereaction process was a diffusion-controlled one and the electrochemical oxidation involved two electronstransferring and two protons participation. Furthermore, the charge-transfer coefficient (α), and the electrodereaction rate constant (kf) of VEN were found to be 0.91 and 3.04×10−2 s−1, respectively. Under theoptimized conditions, the electrocatalytic oxidation peak currents were linearly dependent on the concentrationof VEN in the concentration range from 2.0×10−6 mol L−1 ~ 2.0×10−3 mol L−1 with the limit ofdetection (S / N = 3) as 1.69×10−6 mol L−1. The proposed method has been successfully applied in the electrochemicalquantitative determination of VEN content in commercial venlafaxine hydrochloride capsulesand the determination results could meet the requirement of the quantitative determination.