Ascorbic Acid Sensor Using Modified Pencil Graphite Electrodes: A Preliminary Study

This study aimed to develop an electrochemical sensor based on a derivative of graphene oxide (GO) and a molecularly imprinted polymer (MIP) on a pencil graphite electrode (PGE) for the detection of ascorbic acid (AA). MIP was fabricated onto the surface of the electrode by electropolymerization technique using cyclic voltammetry with a scan rate of 10 mV/s consisting of template molecule (ascorbic acid), functional monomer (polypyrrole), cross-linker (LiClO₄) and citrate buffer at pH 4. Then, the template removal process was conducted to create the imprinted cavities for detecting the analyte. Differential pulse voltammetry (DPV) and cyclic voltammetry (CV) methods were used to perform quantitative analyses of the modified electrodes. CV analysis was performed at the optimum scan rate of 10 mV/s, and the electrolyte concentration at 1.0 mM K₃[Fe(CN)₆] in 0.1 M KCl. MIP-PGE (2) produced the best performance by having the highest redox peak current response when scanning with the CV compared to other modified electrodes. The optimum parameters for DPV measurement are 100 mV pulse amplitude, 200 ms pulse period, and 10 mV/s scan rate. The straightforward instrumentation and easy preparation of the proposed sensor make it a valuable system for constructing simple devices for determining ascorbic acid.