Determination of strobilurin fungicides residual in vegetables based on amino modified magnetic graphene oxide solid phase extraction coupled with GC–MS/MS

Abstract

This research investigated the creation and utilization of an amino-functionalized magnetic graphene oxide (Fe₃O₄-NH₂@GO) nanocomposite as a selective sorbent for extracting and identifying strobilurin fungicides (SFs) from vegetable samples. The investigation utilized a method where magnetic solid phase extraction (MSPE) was integrated with Gas chromatography-triple quadrupole mass spectrometer (GC–MS/MS) for analysis. The physicochemical properties of synthesized sorbent were characterized using Scanning electron microscope (SEM) , Fourier infrared transform spectrum (FT-IR) , X Ray Diffraction (XRD), and vibrating sample magnetometry (VSM) techniques. The adsorption performance of Fe₃O₄-NH₂@GO aligned with the pseudo-second-order kinetics, Elovich, and Freundlich isothermal adsorption models, suggesting various interactions with SFs, including π-π interactions, hydrogen bonding, and electrostatic forces. The maximum adsorption capacity of two selected representative SFs (Picoxystrobin and E-metominostrobin) for the adsorbent were 55.85 mg/g and 47.35 mg/g, respectively. Additionally, the amino group exhibited notable potential for SFs adsorption. Parameters for MSPE, such as the quantity of sorbent, adsorption duration, eluent types and volumes, and sample pH, were optimized. Under optimal conditions, the developed method showed satisfactory performance within a range of 10 to 2000 µg L⁻¹ (R² ≥ 0.9969), low detection limits (0.01–0.080 µg/kg), high analyte recovery (80.5–104.3 %), and good precision (RSD ≤ 4.96 %, n = 6). This method is rapid, straightforward, environmentally friendly, demonstrates good sensitivity and providing a new perspectives on developing sorbents for SFs in complex food matrices. Also Fe₃O₄-NH₂@GO as a sorbent firstly used for extraction and enrichment of phenyl fungicides residues in food samples exhibits remarkable promise, thereby contributing to the advancement of pesticides residue determination methodologies.