Simultaneous Voltammetric Determination of Vitamine B9 and Vitamine B12 using a Hydroquinone Derivaive Multi-Wall Carbon Nanotubes Paste Electrode

In this study, the electro-oxidation of vitamin B9 and vitamin B12, and their mixture has been studied by modified multi-wall carbon nanotubes paste electrode of 4-hydroxy-2-(triphenylphosphonio)phenolate (HTP) using cyclic voltammetry, chronoamperometry and differential pulse voltammetry. The modified electrode exhibited potent andpersistent electron mediating behavior followed towards vitamin B9 with activation overpotential. The cyclic voltammetric responses of the modified electrode at various scan rates which were obtained in a 0.18 mM of vitamin B9 solution, showed thecharacteristic shape typical of an ECcat process. Cyclic voltammetry and chronoamperometry were used for estimating electron transfer coefficient (α) anddiffusion coefficient (D) for oxidation of vitamin B9 at the modified electrode respectively. The obtained catalytic peak current by differential pulse voltammetry waslinearly dependent on the vitamin B9 concentration over the range 1.5-135.3 μM with limit of detection 0.2 μM. For a binary mixture containing vitamin B9 and vitamin B12, the two well distinguished differential pulse voltammograms were obtained in pH 7.0.Therefore, simultaneous determination of vitamin B9 and vitamin B12 using modified electrode is possible. Linear calibration curves were obtained for 5.3–62.5 μM of vitamin B9 and 6.2–75.0 μM of vitamin B12.