A Molecular Imprinted Bi-Polymer Graphite Electrode Decorated With NiCo₂O₄ Nano-Cubes for Rapid Detection of Theaflavin in Black Tea

Theaflavin (TF) is a major constituent in tea and is responsible for quality profiling in terms of taste attributes. This research aims to fabricate a molecular imprinted electrode modified with nanoparticles of nickel cobalt oxide for the detection of TF in tea. The proposed electrode is prepared from a co-polymer of acrylic acid (AA) and methacrylic acid (MAA) and imprinted with TF template. The nanoparticles of nickel cobalt oxide are prepared in the laboratory and further characterized by Fourier transform infrared (FTIR) and scanning electron microscope (SEM). Cyclic and differential pulse voltammetry (DPV) is performed to study the electrochemical behavior of the electrode. The electrode shows a good detection limit of 13.89 $\mu $ M and has a wide linear operating range of 80–1000 $\mu $ M. The electrode is repeatable and shows satisfactory reproducibility. The proposed electrode is also employed to determine the total TF in different black tea samples by correlating with standard high-performance liquid chromatography (HPLC) values using the partial least square regression (PLSR) model and a prediction accuracy of 92.6% is obtained.