Electrochemical detection of fenthion insecticide in olive oils by a sensitive non-enzymatic biomimetic sensor enhanced with metal nanoparticles

Fenthion (FEN) is an organophosphate insecticide that has a cholinesterase inhibitory effect and very high toxicity to the natural ecosystem. This paper describes a new approach for FEN detection via an electrochemical sensor based on molecularly imprinted polymer (MIP). This synthetic receptor is fabricated by first immobilizing a 2-aminothiophenol (2-ATP) mixed with gold nanoparticles (AuNPs) on a screen-printed gold electrode (Au-SPE). Then, the FEN template was linked on Au-SPE/ATP-AuNPs before being covered with 2-ATP polymer membrane. The morphological characterization of the electrode's surface was performed using scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier transforms infrared spectroscopy (FT-IR). Cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy methods were used for the electrochemical characterization. The proposed MIP sensor exhibits a low detection limit of 0.04 µg/mL over a range of 0.01-17.3 µg/mL. Additionally, the sensor was successfully applied for the FEN determination in olive oil samples with recovery values of 87.5%- 96%. These results deduced that the developed electrochemical MIP sensor could be a promising candidate for organophosphate insecticide detection in real samples.