Determination of nitrofuran metabolites in fish samples by boronate affinity extraction coupled to HPLC-MS/MS using cis diol-modified mesoporous polymer (GMA-EGDMA) microspheres as adsorbents

In this study, we present a simple and rapid boronate affinity extraction methodology for the HPLC-MS/MS analysis of four nitrofuran metabolites (NFMs) including SEM, AOZ, AHD and AMOZ in fish samples. To enhance the efficacy of this approach, mesoporous poly(GMA-EGDMA) microspheres, abundant in cis-diols, were synthesized for boronate affinity extraction. Meanwhile, 4-fluoro-3-formylphenyl boronic acid was utilized for the derivatization of NFMs, facilitating the immobilization of boronate ligands onto their molecular structures. Compared to the Chinese national food safety standard GB 31656.13–2021, the boronate affinity extraction eliminates the need for extraction solvents and centrifugation, streamlines the pretreatment process, and maintains a mild extraction environment. Furthermore, the poly(GMA-EGDMA) microspheres exhibited excellent reusability, retaining their performance over six adsorption-desorption cycles. The NFMs demonstrated excellent linearity (R² > 0.999) across the range of 0.5 to 50 µg kg⁻¹ . The quantitative limit was established at 0.5 µg kg⁻¹ . The recoveries of spiked tilapia samples ranged from 94.2 % to 110.7 %, while intra-day and inter-day RSDs were below 5.9 %. This method emerges as an economical, straightforward, rapid, and sensitive alternative for monitoring of NFM residues in aquatic products.