Thiamethoxam is a class of neonicotinoid insecticide widely used in agriculture. Due to their high water solubility, thiamethoxam can be transported to surface waters and have the potential to be toxic to human life. Herein, a simple and robust method is presented for the detection of thiamethoxam based on hydrothermally synthesized nanoparticles of cobalt oxide into the graphitic carbon nitride composite (Co3O4@g-C3N4 NC). The materials were well characterized by XRD, FT-IR, XPS, FESEM, HRTEM, EDX, and UV-vis which provide crystalline nature, structure, and composition. The impedance measurement shows an intimate electrode/electrolyte interface by casting Co3O4@g-C3N4 onto a screen-printed carbon electrode (SPCE), delivering an interfacial resistance as low as 12.5 Ωcm2. The cyclic voltammetry and differential pulse voltammetry measurements exhibit the nanocomposite as a superior electrocatalyst for the electrochemical detection of thiamethoxam and achieved a low detection limit of 4.9 nM with a wide linear range of 0.01-420 μM. The present work also demonstrates a promising strategy for electrochemical detection of thiamethoxam in real samples such as potato and brown rice.
Keywords: Differential pulse voltammetry; Electrochemical sensor; Insecticide; Neonicotinoids; Screen-printed carbon electrode.
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