Mohamed Abd-Elsabour - Faculty of Science, Chemistry Department, South Valley University, Qena, ۸۳۵۲۳, Egypt
Keriman Abd-Elsabur - Faculty of Science, Chemistry Department, South Valley University, Qena, ۸۳۵۲۳, Egypt
Fawzy Assaf - Faculty of Science, Chemistry Department, South Valley University, Qena, ۸۳۵۲۳, Egypt
Ibrahem Hasan - Faculty of Science, Chemistry Department, South Valley University, Qena, ۸۳۵۲۳, Egypt

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 B۲ (VB۲) in PBS buffer solution. The sensor was applied for individual and simultaneous determination of AA and VB۲using cyclic and differential pulse voltammetry (DPV) techniques. Different experimental parameters including scan rate(۲۵-۵۰۰ mV/s), pH (۴-۸ for AA and ۳-۱۰ for VB۲) and analyte concentration (۱۰-۴۰ µM for AA and ۴-۸۵ µM for VB۲) have been studied and optimized. High electrocatalytic activities for AA and VB۲ oxidation were achieved at pH ۷.۰ and ۶.۰, respectively. In addition, results denoted that the oxidation process of AA and VB۲ was under diffusion control. The respective detection limits, quantitation limits and linear ranges were ۰.۵۷۵, ۱.۹۱۶ and ۱۰-۴۰ μM for AA and ۰.۹۲۲, ۳.۰۷۳ and ۵-۸۵ μM for VB۲under the optimized DPV conditions. Peak separation of AA from VB۲was ۶۶۰ mV which is enough to determine these vitamins simultaneously. The fabricated sensor has been applied successfully for estimation of AA and VB۲ in real samples with good selectivity, stability and reproducibility.

Ascorbic acid, Riboflavin, Electropolymerization, Methyl Orange, Cyclic Voltammetry, Differential pulse voltammetry