Molecular Docking and Density Functional Studies of Selective Molecularly Imprinted Polymers Combined with an Electrochemical Sensor for the Detection of Malathion

In this research, density functional theory and molecular docking calculations were utilized to select appropriate molecularly imprinted polymers (MIPs) for malathion (MAL). The MIP was synthesized with MAL as the template molecule, ethylene glycol dimethacrylate as the cross-linker, and methacrylic acid as the functional monomer on the surface of graphene quantum dots (GQDs). The MIPs were coated on GQDs to fabricate the GQDs@MIP sensor. The electrochemical sensor was characterized by Fourier-transform infrared spectroscopy, X-ray scattering spectroscopy, and field-emission scanning electron microscopy. Parameters affecting the electrochemical response of MAL, including the GQDs@MIP percentage amount, pH of the rebinding solution, pH of the analysis solution, and incubation time, were optimized. Differential pulse voltammetry revealed a linear calibration curve in the concentration range of 0.01 to 55.00 µM with a limit of detection of 1.5 nM. The relative standard deviation for five consecutive tests of 1.00 μM MAL was 2.2%. The GQDs@MIP sensor was successfully applied to determine MAL in various fruit samples.