Magnetic covalent organic frameworks based on magnetic solid phase extraction for determination of six steroidal and phenolic endocrine disrupting chemicals in food samples

A simple and rapid magnetic covalent organic frameworks based on magnetic solid phase extraction method was proposed for effective determination of six steroidal and phenolic endocrine disrupting chemicals in meat samples. Fluorescence labeling combined with high performance liquid chromatography fluorescence detection was used to quantify endocrine disrupting chemicals. Covalent organic frameworks could be a wonderful choice as sorbent for endocrine disrupting chemicals enrichment due to its characteristics of large specific surface area, great structure stability and functional properties. In this work, COF(TpBD) was chosen as functionalized groups to be grafted onto the surface of Fe3O4 microspheres via one-step surface fabrication strategy. The parameters affecting the extraction efficiency were investigated in detail. The adsorption equilibrium was achieved within 5 min. Under the optimized conditions, the obtained Fe3O4@COF(TpBD) materials showed excellent extraction performance for endocrine disrupting chemicals with high sensitivity (1.4-8.7 μg L−1 for LODs and 4.6-29.0 μg L−1 for LOQs) and good linearity (R ≥ 0.9986). Determination of endocrine disrupting chemicals in meats was achieved using the proposed method. Furthermore, the method, validated on spiked meats (including chicken, pork and shrimp), showed satisfactory accuracy, with average recoveries in the 89.6-108.9% range and relative standard deviations ≤6.3%. Additionally, two kinetic models were investigated to recognize the target analytes adsorption mechanism onto Fe3O4@COF(TpBD) materials, and the results indicated that the pseudo-second-order model was the most suitable in describing the adsorption kinetics of endocrine disrupting chemicals on the Fe3O4@COF(TpBD) materials. The proposed method was proved to be feasible for the determination of endocrine disrupting chemicals in complex food samples.