Adsorptive Stripping Voltammetric Determination of Venlafexine at a Carbon Nanocomposite Ionic Liquid Electrode

A carbon nanocomposite electrode has been designed by incorporation of multiwalled carbon nanotubes (MWCNT) into ionic liquid 1-octylpyridinium hexa flourophosphate (OPFP) that can be well used as an electrode for electrocatalytic oxidation of venlafaxine (VEN). This drug is an antidepressant which inhibits reuptake of serotonin, norepinephrine. However, an overdose of VEN results in the most common symptoms such as depression, serotonin toxicity, seizure, or cardiac conduction abnormalities. Hence, their determination is of great significance.[1]One of the dominant techniques for detecting trace levels of VEN is chromatography.2 However, this method has disadvantages of being expensive, effortful, and time-consuming sample pre-treatment. Electrochemical techniques are good candidates for the analysis of VEN because of their simplicity, low-cost, rapidity and sensitivity. Moreover, concerning the electrochemical measurements of VEN, only a few reports are available.3, 4To the best of our knowledge, the electrochemical behavior of VEN was not studied at carbon paste electrodes. In the present study, Adsorptive stripping voltammetry was applied as a sensitive analytical method for the determination of VEN in pharmaceutical formulations as well as blood serum. The effects of amount of multi-walled carbon nanotube used for the modification of the carbon ionic liquid electrode (CILE), pH of the solution, accumulation potential, accumulation time and scan rate on the response of modified electrode for the oxidation of VEN were investigated.The oxidation peak potential of VEN appeared at 640 mV at the MWCNT modified carbon ionic liquid electrode (MWCNT/CILE) in the 0.1 M phosphate buffer solution (PBS), pH 9.0 containing 1mM of VEN, that is about 150 mV lower than the peak potential at traditional carbon paste electrodes. Under the optimum conditions, the anodic peak current was linear to VEN concentration in the ranges of 10.0 to 500.0 μM. Low detection limit of 0.47 μM was found. The proposed electrode has the features of being sensitive, reproducible, easily renewable and cost effective. Determination of VEN in pharmaceutical formulations and blood sample were performed with MWCNT/CILE.