Utilization of a MnO₂/polythiophene/rGO nanocomposite modified glassy carbon electrode as an electrochemical sensor for methyl parathion

The present work describes the utility of an inexpensive modified electrode for the electrochemical detection of an organophosphorus pesticide, methyl parathion (MP). A glassy carbon electrode was modified with MnO₂/PTH/rGO nanocomposite (where PTH = polythiophene and rGO = reduced graphene oxide), which was prepared by in situ chemical oxidative polymerization method. Its morphology, diffraction, impedance and electrochemical measurement were studied using FTIR, XRD, Raman spectra, SEM, HR-TEM with EDX, cyclic voltammetry, differential pulse voltammetry and amperometric techniques. The modified glassy carbon electrode of MnO₂/PTH/rGO film delivers an excellent electrocatalytic ability due to the presence of MnO₂ and rGO. It also exhibited a high sensitivity of 0.0498 µA µM⁻¹ cm⁻² and limit of detection (LOD) of 5.72 nM. A synergistic effect of the components rGO, PTH and MnO₂ accounts for high sensitivity, selectivity, acceptable reproducibility and good stability, which characterizes a promising tool for ultrasensitive detection of methyl parathion. Besides, practical possibility of the sensor was demonstrated in biological samples which delivered excellent recovery results.