One-pot synthesis of magnetic covalent organic frameworks for highly efficient enrichment of phthalate esters from fine particulate matter

Phthalate esters (PAEs) are a typical group of endocrine-disrupting chemicals (EDCs) and widely found in the environment, which have attracted great concern due to the potential risks to environment and human health. It is urgent to develop a high-efficiency and high-sensitivity analytical approach for enrichment and determination of ultra-trace PAEs. Herein, magnetic covalent organic frameworks (Fe₃O₄@TAPB-DVA) were fabricated via a one-pot approach at room temperature and explored as a magnetic enrichment probe with high surface area (275.50 m²/g), good crystallinity, regular pore size distribution (3.1 nm) and outstanding saturation magnetization (26.5 emu/g). Accordingly, a simple and sensitive method based on magnetic solid-phase extraction (MSPE) combined with HPLC-MS/MS was established to detect ultra-trace PAEs from fine particulate matter (PM_2.5) samples. The proposed method showed wide linear ranges (1-400 ng/L), good linearity (r > 0.9978) and high enrichment factors (EFs, 6.99-95.01 folds) with low detection limits (LODs) ranged from 0.01 to 0.5 ng/L (S/N ≥ 3). On this basis, the proposed method was substantially employed for sensitive detection of low- abundance PAEs from PM_2.5 samples, suggesting the promising application of the Fe₃O₄@TAPB-DVA in sample enrichment.