Theoretical and experimental studies of a novel electrochemical sensor based on molecularly imprinted polymer and GQDs-PtNPs nanocomposite

A new molecularly imprinted polymer (MIP) electrochemical sensor was prepared applying one-step electro-copolymerization of 3, 4-ethylenedioxythiophene (EDOT) and methacrylic acid (MAA) in the presence of sulfadimidine as a template molecule on a glassy carbon electrode (GCE) which modified with graphene quantum dots (GQDs)-Pt nanoparticles (PtNPs). A computational approach was employed to screen the suitable functional monomer, and the simulation data suggested that EDOT and MAA as bifunctional monomers exhibited a preferable capability to recognize the target molecule compared to other monomers. The MIP material was characterized with scanning electron microscope (SEM), transmission electron microscope (TEM) and electrochemical impedance spectroscopy (EIS). The performance of MIP sensor was evaluated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The results indicated that the electro-copolymerization of EDOT and MAA provides large amounts of functional groups for the binding of the template molecules, which significantly enhances the sensitivity of the MIP sensor. The calibration curve demonstrated linearity over a concentration range of 0.1 nM-0.1 mM with a detection limit of 0.023 nM. This study provides complete and valuable information on the rational design, preparation, and application of sulfadimidine molecularly imprinted polymers using advanced materials and new bi-functional monomers.