Development of a magnetic dispersive solid phase extraction method by employing folic acid magnetic nanoparticles as an effective, green, and reliable sorbent followed by dispersive liquid-liquid microextraction for the extraction and preconcentration of seven pesticides from fruit juices

Folic acid magnetic nanoparticles have been prepared and utilized as an effective and reliable sorbent in magnetic dispersive solid phase extraction combined with dispersive liquid-liquid microextraction for the extraction of seven pesticides from different juices before their determination by gas chromatography–flame ionization detector. The sorbent is prepared through ball milling process using a proper mixture of folic acid and magnetic iron oxide. Characterization of the sorbent was done with X-ray diffraction pattern, scanning electron microscopy, and vibrating sample magnetometry. In the current study, limits of detection were in the range 0.12–0.33 μg L⁻¹. Relative standard deviations at a concentration of 40 μg L⁻¹ of each analyte were in the ranges of 2.15–5.14% for intra-day (n = 6) and 3.78–6.91% for inter-day (n = 4) precisions. Extraction recoveries and enrichment factors were obtained in the ranges of 70–88 % and 566–708, respectively. The performance of the method was evaluated by determination the selected pesticides in different samples.