A novel molecularly imprinted electrochemical sensor based on MnO-Fe3O4@C was designed with DFT theoretical study for the detection of thiamphenicol in food

Abstract

In this study, a new molecularly imprinted electrochemical sensor is presented for thiamphenicol (TAP) based on MnO-Fe₃O₄@C and a molecularly imprinted polymer (MIP). In the synthesis process of MIP, the density functional theory (DFT) was applied to simulated the interaction between different functional monomers and template molecules, and screen the optimal functional monomers and the ratio of optimal template molecules to functional monomers, which guided the electrochemical in-situ polymerization of MIP. The composite materials were evaluated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), and the electrochemical performance of molecular imprinted electrode was evaluated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Under the optimal conditions, there is a strong linear correlation between the current response and TAP concentration in the 0.01–1 μM (R²=0.9988) and 1–40 μM (R²=0.9954) range. The lowest detection limit (S/N = 3) was 0.007 μM. Besides, the sensor has good reproducibility, stability and anti-interference ability, and has successfully detected analytes in milk and egg samples, which provides application prospects for constructing selective detection of TAP in food samples.