An Electrochemical Sensor Based on Poly(methyl orange) Modified Glassy Carbon Electrode for Simultaneous Determination of Vitamins B2 and C in Aqueous Solution

A selective and sensitive voltammetric sensor was constructed using a Poly(methyl orange)/glassy carbon electrode (PMO/GCE). The PMO/GCE sensor was applied to investigate the electrochemical behavior of ascorbic acid (AA) and vitamin B2 (VB2) in the PBS buffer solution. The sensor was applied for the individual and simultaneous determination of AA and VB2using cyclic and differential pulse voltammetry (DPV) techniques. Different experimental parameters including scan rate (25-500 mV s-1), pH (4-8 for AA and 3-10 for VB2) and analyte concentration (10-40 μM for AA and 4-85 μM for VB2) have been studied and optimized. High electrocatalytic activities for oxidation of AA and VB2 were performed with pH values of 7.0 and 6.0, respectively. In addition, the results indicated that the oxidation process of AA and VB2 was under diffusion control. The detection limits, quantitation limits and linear ranges were 0.575, 1.916 and 10- 40 μM for AA and 0.922, 3.073 and 5-85 μM for VB2, respectively, under the optimized DPV conditions. Peak separation of AA from VB2 was 660 mV which is enough to determine these vitamins simultaneously. The fabricated sensor has been applied successfully for estimation of AA and VB2 in real samples with good selectivity, stability and reproducibility.