A novel detection method for organophosphorus insecticide fenamiphos: Molecularly imprinted electrochemical sensor based on core-shell Co3O4@MOF-74 nanocomposite

Abstract

Organophosphorus insecticide fenamiphos (FEN) is utilized to control the detrimental nematode pests. In this report, a novel molecular imprinted electrochemical sensor for insecticide FEN detection was prepared. The molecular imprinted sensor was prepared based on Co3O4 nanowire and core-shell Co3O4@MOF-74 nanocomposite. Firstly, hydrothermal method followed by thermal annealing was applied for the preparation of Co3O4 nanowire. Then, solvothermal technique was used in no presence of metal salts to prepare core-shell Co3O4@MOF-74 nanocomposite. In addition, several solvothermal cycles were tried to optimally adjust the reaction efficiency. After the modification of the clean carbon electrode surfaces with Co3O4@MOF-74 nanocomposites, the molecular imprinted electrodes based on Co3O4@MOF-74 nanocomposites were prepared in presence of 100.0 mM pyrrole as monomer and 25.0 mM FEN as analyte molecule between +0.30 V and +1.50 V by cyclic voltammetry (CV). The prepared molecularly imprinted sensor based on Co3O4 nanowire and core-shell Co3O4@MOF-74 nanocomposite was characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), xray diffraction (XRD) method, x-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and CV. The quantification limit (LOQ) and the detection limit (LOD) were obtained as 1.0 x 10(-11) M and 3.0 x 10(-12) M, respectively, by using the developed sensor. Hence, the developed molecularly imprinting electrochemical sensor having high selectivity, stability and reproducibility was presented in this study for insecticide FEN detection. (C) 2021 Elsevier Inc. All rights reserved.