An Improved Stir Fabric-Phase Sorptive Extraction Combined with Ultra-High-Performance Liquid Chromatography–Tandem Mass Spectrometry Analysis for the Determination of 48 Pesticide Residues in Vegetable Samples

Fabric-phase sorptive extraction (FPSE) coats organic–inorganic hybrid sorbent materials onto flexible and hydrophilic fabrics through sol–gel sorbent-coating technology. Herein, we explored four different coating chemistries, including those of nonpolar sol–gel poly(dimethylsiloxane), medium polar sol–gel poly(tetrahydrofuran), and polar sol–gel poly(ethylene glycol) (PEG)–block-poly(propylene glycol)–PEG, and sol–gel PEG. Results showed that PEG had the best extraction recoveries for the majority of the analytes. Subsequently, strongly polar sol–gels were prepared using PEG as precursor and FPSE medium. FPSE was then combined with a cut solid-phase extraction column and immobilised with magnetic-stirring beads so that FPSE could be automatically stirred magnetically throughout the entire extraction process. The developed method based on ultra-high-performance liquid chromatography–tandem mass spectrometry showed good linearity within the concentration range of 5–200 ng/mL. Under the optimum experimental conditions, limits of detection for 48 pesticides were obtained within the range of 0.014–6.280 ng/mL. Thereafter, the new method was applied to tomato, cucumber, and cabbage samples. Recoveries ranged from 71.4 to 99.8% at three concentration levels. The various parameters of this experimental method were systematically investigated and optimised to improve its sensitivity and prove its feasibility in vegetables. Overall, our results demonstrated that the method was simple, sensitive, efficient, and rapid. Furthermore, FPSE fibre cloth showed great potential for commercial exploitation because of its reusability.