Fabrication of a Structure-Specific Molecular Imprinted Polymer–Based Electrochemical Sensor Based on CuNP-Decorated Vinyl-Functionalized Graphene for the Detection of Parathion Methyl in Vegetable and Fruit Samples

Abstract

Molecular imprinted polymers on copper nanoparticle–decorated vinyl-functionalized graphene (CuNPs@GR-MIPs) are fabricated. The copper nanoparticles (CuNPs) are synthesized by the reduction of diaminopropane copper complexes (DAPCu) using sodium borohydride as reducing agent. The synthesized CuNPs are successfully decorated on vinyl-functionalized graphene (V-fGR) on which MIPs are fabricated. All intermediates during the synthesis of CuNPs@GR-MIP are characterized in detail by Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, powder X-ray diffraction analysis, transmission electron microscopy, and scanning electron microscopy techniques. The fabricated CuNPs@GR-MIPs are developed as a sensor for organophosphorus pesticide parathion methyl. The recognition cavities formed on CuNPs@GR-MIP during the synthesis are mainly responsible for the sensing property. The result of the electrochemical studies shows that CuNPs@GR-MIP material has good recognition and sensing capacity towards parathion methyl (PM). The sensitivity is found to be directly proportional to the amount of PM molecules in solution with a detection limit of 0.24 × 10−9 mol L−1 (S/N = 3). The selectivity studies of the fabricated CuNPs@GR-MIP sensor give a fine discrimination between PM and its structurally similar compounds such as 2,4-dinitrophenol, nitrobenzene, nitroaniline, p-nitrophenol, ascorbic, dopamine acid, and malathion. Most promisingly, the sensing capacity of the synthesized CuNPs@GR-MIP is successfully demonstrated in vegetables and fruits which shows us the real time applicability of the sensor in food analysis.