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Voltammetric Determination of Vitamin B₆ (Pyridoxine) Using Multi Wall Carbon Nanotube Modified Carbon-Ceramic Electrode

B. Habibi^a,*, H. Phezhhan^a and M.H. Pournaghi-Azar^b

^aElectroanalytical Chemistry Laboratory, Department of Chemistry, Faculty of Sciences, Azarbaijan University of  Tarbiat Moallem, Tabriz, Iran
^bElectroanalytical Chemistry Laboratory, Faculty of Chemistry, University of Tabriz, Tabriz, Iran

      A simple procedure was developed to prepare a carbon-ceramic electrode (CCE) modified with multi wall carbon nanotube (MWCNT). The electrochemical behavior of pyridoxine was investigated on the obtained electrode in phosphate buffer solution (PBS), pH 7.0. During oxidation of pyridoxine on the MWCNT/CCE, one irreversible anodic peak at E_p = 716 mV vs. SCE appeared. Cyclic voltammetric study indicated that the oxidation process is irreversible and diffusion controlled. The number of exchanged electrons in the electro-oxidation process was obtained, and the data indicated that pyridoxine is oxidized via two one-electron steps. The results revealed that MWCNT promotes the rate of oxidation by increasing the peak current, so that pyridoxine is oxidized at lower potentials, which thermodynamically is more favorable compared with on the bare CCE. A sensitive, simple and time-saving differential pulse voltammetric procedure was developed for the analysis of pyridoxine. Using the proposed method, pyridoxine can be determined with a detection limit of 95 nM. The applicability of the method to direct assays of some commercial pharmaceutical samples is described.  

Keywords: Vitamin B6, Pyridoxine, Voltammetric detection, Multi wall carbon nanotube, Carbon-ceramic electrode