A simple and efficient magnetic solid-phase extraction (MSPE) method was established with magnetic covalent organic framework (COF) as adsorbent to enrich organophosphorus pesticides from fatty milk samples, followed by the sensitive determination via LC-MS/MS. The key parameters influencing the MSPE efficiency were comprehensively investigated to afford an optimized procedure. All the target analytes could be captured directly by magnetic COF from milk without protein precipitation, making the pretreatment rapid and convenient. Systematic method validation demonstrated its satisfactory linearity, recoveries (80.0-105 %), and precision (RSDs <12.3 %). The method limits of quantification were 0.2-0.5 μg L⁻¹. A comparison experiment to the reported solid-phase extraction fully verified the present MSPE more rapid, accurate, and environment-friendly. Furthermore, FT-IR and XPS analysis were performed to reveal the adsorption mechanisms of magnetic COF to organophosphorus pesticides, which could offer guidance on the rational design of COF adsorbent for various target analytes.

建立了以磁性共价有机骨架（COF）为吸附剂，从脂肪乳样品中富集有机磷农药的简单高效的磁性固相萃取（MSPE）方法，然后通过LC-MS / MS进行灵敏测定。全面研究了影响MSPE效率的关键参数，以提供优化的程序。磁性COF可以直接从牛奶中捕获所有目标分析物，而不会沉淀蛋白质，从而使预处理快速便捷。系统方法验证证明了其令人满意的线性，回收率（80.0-105％）和精密度（RSDs <12.3％）。方法的定量限为0.2-0.5μgL ^-1。与报道的固相萃取进行的对比实验充分证明了本MSPE更加快速，准确和环境友好。此外，进行了FT-IR和XPS分析，揭示了磁性COF对有机磷农药的吸附机理，这可为合理设计各种目标分析物的COF吸附剂提供指导。