Simultaneous Voltammetric Determination of Ascorbic Acid and Uric Acid Using a Modified Multiwalled Carbon Nanotube Paste Electrode

This paper describes the development, electrochemical characterization and utilization of novel modified molybdenum (VI) complex-carbon nanotube paste electrode for the electrocatalytic determination of ascorbic acid (AA). The electrochemical profile of the proposed modified electrode was analyzed by cyclic voltammetry (CV) that showed a shift of the oxidation peak potential of AA about 235 mV to less positive value, compared with an unmodified carbon paste electrode. Differential pulse voltammetry (DPV) in 0.1 M phosphate buffer solution (PBS) at pH 7.0 was performed to determine AA in the range of 0.1 to 950.0 ?M, with a detection limit of 89.0 nM. Then the modified electrode was used to determine AA in an excess of uric acid (UA) by DPV. Finally, this method was used for the determination of AA in some real samples.