A Novel Co/Zn-Ferrite Molecularly Imprinted Polymer Sensor for Electrochemical Detection of Gallic Acid

Abstract

In this study, we present the development of a novel electrochemical sensor based on molecularly imprinted polymers (MIPs) for the selective and sensitive detection of gallic acid (GAL) in real samples, including plant extracts, wine, and herbal supplements. Gallic acid is widely recognized for its significant antioxidant properties and associated biological effects, such as anticancer, anti-inflammatory, and antimicrobial activities. To enhance the electrochemical performance of the sensor, cobalt-zinc-ferrite coated with dihydrocaffeic acid (CFO_Zn_DHCA) nanoparticles, characterized by their spherical morphology and an average particle size of 5±1 nm, were incorporated into the MIP matrix. The resulting GA/CFO_Zn_DHCA/3-APBA@MIP-GCE sensor exhibited a rough and porous morphology due to imprinting process, as examined using scanning electron microscopy (SEM). Electrochemical properties were investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The sensor exhibited a linear detection range of GAL from 10⁻13 to 10⁻12 M in a 5.0 mM [Fe(CN)₆]3⁻/4⁻ redox electrolyte, with calculated values of limit of detection (LOD) and limit of quantification (LOQ) of 1.29×10⁻14 and 4.29×10⁻14 M, respectively. The developed MIP-based electrochemical sensor demonstrated excellent performance in terms of sensitiviy, selectivity and reproducibility and was successfully applied for the detection of GAL in complex real-world matrices such as pomegranate peel, green and black tea, wine and various herbal supplements.