Ionic liquid-modified magnetic covalent organic framework for the extraction of four pyrethroids in traditional Chinese herbs

• IL-COF@Fe 3 O 4 possessed excellent adsorption performance towards pyrethroids within 5 mins. • ILs improved the extraction capacity resulted from the interaction of imidazole and Cl or F and the pore size effect . • The established method had desirable linear ranges and low limits of detection towards pyrethroids . • IL-COF@Fe 3 O 4 exhibited weak matrix interference effect in traditional Chinese medicine . Efficient enrichment of analytes and purification of matrices are crucial for the highly sensitive detection and monitoring of pesticides in traditional Chinese herbs. This work prepared magnetic ionic liquid-controlled covalent organic framework (IL-COF@Fe 3 O 4 ) as the sorbent via a simple in-situ precipitation polymerization and thiolene “click” strategy. The IL-COF@Fe 3 O 4 exhibited remarkable adsorption performance towards pyrethroids within 5 min. The adsorption of four pyrethroids on the surface of IL-COF@Fe 3 O 4 was according with Langmuir model and pseudo-second-order kinetic model. The adsorption energies were theoretically calculated, which were permethrin>cypermethrin>fenvalerate>bifenthrin. The modification of ILs improved extraction capacity mainly because of the interaction of imidazole and Cl or F and the pore size effect. This method was developed for the rapid extraction of four pyrethroids in Codonopsis pilosula and Angelica sinensis . The linear range was 0.05–200 μg L -1 . Matrix effects were ranging from -16.14% to 9.53%, indicating the strong matrix anti-interference ability of IL-COF@Fe 3 O 4 .