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

Theaflavin 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 theaflavin in tea. The proposed electrode is prepared from a co-polymer of acrylic acid and methacrylic acid and imprinted with theaflavin 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 is performed to study the electrochemical behaviour of the electrode. The electrode shows a good detection limit of 13.89 μM and has a wide linear operating range of 80 to 1000 μM. The electrode is repeatable and shows satisfactory reproducibility. The proposed electrode is also employed to determine the total theaflavin in different black tea samples by correlating with standard HPLC values using the partial least square regression model and a prediction accuracy of 92.6 % is obtained.