Magnetic polypyrrole/Fe3O4 particles as an effective sorbent for the extraction of abamectin from fruit juices using magnetic solid-phase extraction combined with dispersive liquid–liquid microextraction

Abstract

In this study, magnetic polypyrrole/Fe₃O₄ nanoparticles were synthesized and employed as a novel sorbent for the magnetic solid-phase extraction of abamectin (a mixture of avermectines, B_1a and B_1b), an important insecticide used in agriculture. The properties of the prepared magnetic sorbent were characterized using field emission-scanning electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometry, X-ray diffraction and thermal gravimetric analysis methods. Magnetic solid-phase extraction was carried out together with dispersive liquid–liquid microextraction to enhance preconcentration of abamectin. The effects of the various different parameters influencing the efficiency of the hybrid extraction, such as sorbent amount, extraction time and ionic strength, were investigated and optimized. The enrichment factors obtained using the proposed method were 327 for B_1a and 203 for B_1b. The detection limits of the method under optimized conditions were 0.2 and 1.2 μg L⁻¹ for B_1a and B_1b, respectively. The relative standard deviation obtained for B_1a was 2.1% (n = 5), at a concentration of 5 μg L⁻¹ and that calculated for B_1b was 2.5% at 10 μg L⁻¹. Calibration curves for abamectin showed linearity in the ranges 0.9–1000 μg L⁻¹ and 5–1000 μg L⁻¹ for B_1a and B_1b, respectively. A comparison of the data obtained using the magnetic polypyrrole/Fe₃O₄ nanoparticles with data obtained using other sorbents, such as naked Fe₃O₄ nanoparticles, polypyrrole, C₁₈ and CNT, demonstrated the superior capability of the synthesized composite. The proposed method was also successfully applied to the extraction of abamectin from fruit juice samples, and satisfactory relative recoveries were obtained.