Molecularly Imprinted Polymer-Based Electrode for Tannic Acid Detection in Black Tea

The present study aims at developing a low-cost and reliable electrode based on the molecularly imprinted polymer (MIP) technology for the detection and quantification of tannic acid (TAN) in black tea samples. The material was synthesized using a copolymer of acrylic acid (AA) and ethylene glycol dimethacrylate (EGDMA), a cross-linker, on a graphite bed. The developed electrode material was characterized by ultraviolet–visible (UV–Vis) spectroscopy and scanning electron microscope (SEM). The performance of the electrode was evaluated by a three-electrode configuration using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The devised electrode (MIP_TAN) has shown a wide linear range of performance from 0.1 to 500 $\mu \text{M}$ with a limit of detection (LOD) of 37 nM and evinced high repeatability, reproducibility, stability, and good selectivity. To predict the content of TAN, a partial least square regression (PLSR) model was developed utilizing DPV responses of the electrode and high-performance liquid chromatography (HPLC) as reference data. The prediction accuracy of PLSR was obtained as 96.315%. The electrode was examined on real samples of black tea, which produced satisfactory results.