Electrochemical Salicylic Acid Sensor Based on Molecularly Imprinted Polypyrrole

This study aims to provide new insights into the development of an electrochemical salicylic acid (SA) sensor based on a molecularly imprinted polymer (MIP). Polypyrrole (Ppy) based MIP and nonimprinted polymer (NIP) layers were deposited on the platinum electrode and evaluated in a three-electrode electrochemical cell. The study used amperometry for monomer polymerization, cyclic voltammetry (CV) for the overoxidation of the polymer layer, and differential pulse voltammetry (DPV) for analyte detection. Selectivity was evaluated by comparing the electrochemical signals of SA with those of 3-hydroxybenzoic acid and melamine. Results confirm the selectivity of the electrochemical sensor. Density functional theory (DFT) calculations were performed to analyze the rebinding and recognition mechanism. The results of DFT calculations support the experimental findings. In conclusion, the polypyrrole-based MIP sensor exhibits higher selectivity and sensitivity toward salicylic acid detection compared to melamine and even to its isomer, 3-hydroxybenzoic acid (3-HBA).