Facile room-temperature synthesis of magnetic covalent organic framework nanoflowers for efficient MSPE and detection of avermectins

Avermectins (AVMs) are widely used as broad-spectrum and potent antiparasitic activities. The AVMs residual in animal-derived products and poses potential risks to human health through the food chain. Existing detection methods struggle with ultra-trace residues and matrix interferences in complex samples, necessitating efficient sample pretreatment techniques. This study introduces a novel one-pot in situ synthesis of magnetic covalent organic framework (COF) nanoflowers (Fe 3 O 4 @TFB-TAPA) at room temperature, leveraging a green strategy that eliminates toxic solvents and high-pressure conditions. The unique Fe 3 O 4 @TFB-TAPA nanoflower enhanced surface area and adsorption efficiency, and were comprehensively characterization using XRD, FT-IR, TEM, VSM and TGA. Critical parameters for magnetic solid-phase extraction (MSPE) were optimized. The MSPE protocol was coupled with HPLC-FLD for sensitive detection. The Fe 3 O 4 @TFB-TAPA exhibited exceptional performance: high adsorption capacity due to π-π stacking and hydrogen bonding, superparamagnetic behavior and thermal stability. The method achieved rapid extraction within 5 min and low solvent consumption. Method validation showed wide linear ranges (0.2–600 ng/mL), low detection limits (0.06 ng/mL), and high precision (RSD < 5 %). Reusability exceeded 7 cycles with 96.5 % recovery.