Polyoxometalate-Graphene Nanocomposite Modified Electrode for Electrocatalytic Detection of Ascorbic Acid.

Phosphomolybdate functionalized graphene nanocomposite (PMo12-GS) has been successfully formed on a glassy carbon electrode (GCE) for the detection of ascorbic acid (AA). The obtained PMo12-GS modified GCE, was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy and compared with GCE, GS modified GCE, and PMo12 modified GCE. It shows an increased current and a decrease in over-potential of ∼210 mV. The amperometric signals are linearly proportional to the AA concentration in a wide concentration range from 1×10−6 M to 8×10−3 M, with a detection limit of 0.5×10−6 M. The PMo12-GS modified electrode was employed for the determination of the AA level in vitamin C tablets, with recoveries between 96.3 and 100.8 %. [ABSTRACT FROM AUTHOR]