Membrane–protected magnetic covalent organic framework for efficient extraction of estrogens in dairy products

Abstract

The presence of estrogens residues in dairy products is a growing concern due to their potential health risk. Herein, in this study, we have developed a membrane–protected magnetic solid–phase extraction (MP–MSPE) method that utilized a magnetic adsorbent (Fe3O4@COF–LZU1) with in–situ growth for the efficient extraction of estrone (E1), 17β–estradiol (E2), and estriol (E3). When combined with HPLC–FLD, this method allows for the efficient detection of estrogens in dairy products. The stability of the MP–MSPE was improved by the presence of a dialysis membrane, which remained a high extraction efficiency (90 %) even after ten reuse cycles. The hydrogen bonding, π–π interactions and pore size effect contribute to the excellent adsorption of three estrogens onto Fe3O4@COF–LZU1. Under optimal conditions, the method exhibits a low detection limit (0.01–0.15 μg L−1), wide linear range (0.1–800 μg L−1), and favorable recoveries (77.3 %–109.4 %) at three concentration levels (10, 50 and 100 μg L−1). This proposed method is characterized by its simplicity, high efficiency and eco–friendliness, making it a promising approach for extracting estrogens from dairy products.