Ultra-sensitive electrochemical sensor for fenitrothion pesticide residues in fruit samples using IL@CoFe2O4NPs@MWCNTs nanocomposite

Abstract

In this study, a novel electrochemical sensor was developed for the detection of fenitrothion based on multi-walled carbon nanotubes (MWCNTs), cobalt ferrite nanoparticles (CoFe2O4NPs) and 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim][BF4]) ionic liquid (IL) nanocomposite. The CoFe2O4NPs were synthesized via co-precipitation method and the synthesized nanoparticles S/Nanocomposite was characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermo gravimetric analysis (TGA) and transmission electron microscope (TEM). The obtained results of CV demonstrated that the 7-fold enhancement in the electrochemical signals was achieved with IL@CoFe2O4NPs@MWCNTs@GCE compared to that of a bare GCE. A linear correlation between the peak current and the concentration of FNT (in the range of 0.02–160 µM) was obtained. The estimated limit of detection (3 × SD/Slope) and the limit of quantification (10 × SD/Slope), was found to be 0.0135 µM and 0.0253 µM, respectively. The analytical performance of IL@CoFe2O4NPs@MWCNTs@GCE sensor was successfully evaluated by quantification of FNT in orange as well as in grape fruit extract with satisfactory results.