Structural and functional optimization of COF-coated stirring bars for environmental monitoring and biological sample analysis.

In this study, a series of covalent organic framework (COF)-coated stirring bars-COF-a, COF-b, and COF-c-were innovatively designed and evaluated for the efficient extraction of estrogens from complex environmental and biological samples. The most notable advancement lies in the successful application of COF-c, which exhibited exceptional adsorption capacity, thermal stability, and reusability. Unlike conventional PDMS coatings, COF-c demonstrated enhanced performance in capturing estrogens from actual meat samples, achieving high recovery rates (78.6-119.3%) and maintaining consistent extraction efficiency over multiple cycles. These findings highlight the structural advantages of COF-c, such as its larger pore volume and strong π-π and hydrogen bonding interactions with target molecules. This work underscores the potential of COF-c as a next-generation SBSE coating material, offering a highly selective, thermally stable, and reusable platform for trace hormone analysis in complex matrices.