N-Octylated Magnetic Nanoparticle-Based Microextraction for the Determination of Organophosphorus Pesticides in Water

Abstract

A sensitive and simple procedure based on the dispersive solid phase extraction with hydrophobic n-octyl-modified magnetic iron oxide nanoparticles as the sorbent was developed for the determination of ethoprophos, fenchlorphos, parathion methyl, chlorpyrifos, prothiofos, and azinphos methyl in environmental water samples. Dispersive liquid–liquid microextraction was coupled with dispersive solid-phase microextraction to enhance the dispersibility of the selected sorbent and extraction efficiency. The organophosphorus pesticides were detected using gas chromatography with a flame photometric detector. Under optimized conditions, this method achieved low method detection limit (0.02–0.10 microgram per liter), wide linearity (0.5–800 microgram per liter), high enrichment factors (122–143), good correlation coefficients (r = 0.9975–0.9997), and good repeatability (0.2–7.1 percent). This method was also successfully applied to analyze drinking water and surface water with good extraction efficiency (≥82 percent) and high degree of precision (≤5 percent). The results also indicated that the dispersibility of hydrophobic magnetic nanoparticles was enhanced with liquid–liquid microextraction without chemical modification of the magnetic iron oxide nanoparticles.