Magnetic Persimmon Leaf Composite: Preparation and Application in Magnetic Solid-Phase Extraction of Pesticides in...

In recent years, the utilization of biomass materials for the removal and detection of water pollutants has garnered considerable attention. This study introduces, for the first time, the preparation of Fe₃O₄/persimmon leaf magnetic biomass composites. The magnetic composites were employed in a magnetic solid-phase extraction method, coupled with gas chromatography-electron capture detection (GC-ECD), for the analysis of four pesticides (trifluralin, triadimefon, permethrin, and fenvalerate) in environmental water samples. The innovative magnetic persimmon leaf composites were synthesized by in situ generation of Fe₃O₄ nanoparticles through coprecipitation and loaded onto persimmon leaves. These composites exhibit superparamagnetism with a saturation magnetization of 12.8 emu g^-1, facilitating rapid phase separation using a magnetic field and reducing the extraction time to 10 min. Desorption can be achieved within 30 s by aspirating 20 times, eliminating the need for time-consuming and labor-intensive experimental steps like filtration and centrifugation. The specific surface area of the magnetic composite adsorbent increased from 1.3279 m² g^-1 for the original persimmon leaf to 5.4688 m² g^-1. The abundant hydroxyl and carboxyl groups on the composites provide ample adsorption sites, resulting in adsorption capacities ranging from 55.056 mg g^-1 to 73.095 mg g^-1 for the studied pesticides. The composites exhibited extraction recoveries ranging from 80% to 90% for the studied pesticides. Compared to certain previously reported MSPE methods, this approach achieves equivalent or higher extraction recoveries in a shorter operation time, demonstrating enhanced efficiency and convenience. Good linearity of the target analytes was obtained within the range of 0.75-1500 μg L^-1, with a determination of coefficient (R²) greater than 0.999. These findings contribute to the use of magnetic persimmon leaf biomass materials as effective and environmentally friendly adsorbents for pollutant determination in water samples.