Selective recognition of formononetin using a magnetic molecularly imprinted polymer: A synergistic strategy of deep eutectic solvent and dummy template

A novel DES-assisted dummy template magnetic MIP (DES-MMIP) was fabricated for selective formononetin extraction. • DES-MMIP exhibited high adsorption capacity (26.85 mg·g −1 ) and excellent selectivity (IF = 5.04). • Magnetic separation enabled rapid adsorbent recovery within seconds, eliminating time-consuming centrifugation or filtration. • The DES-MMIP method achieved 97.33–98.67% recoveries from Astragalus extract with a green DES-based synthesis route. Selective separation of low-abundance bioactive compounds from complex herbal matrices remains challenging. Herein, a magnetic molecularly imprinted polymer (DES-MMIP) was developed for rapid and specific recognition of formononetin from Astragalus . For the first time, a dummy template (daidzein), a deep eutectic solvent (ChCl:MAA = 1:2) together with 4-vinylpyridine (4-VP) as dual functional monomers, and Fe 3 O 4 @SiO 2 magnetic nanoparticles were integrated into a single molecularly imprinted system. The material was characterized by transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. Adsorption experiments showed that DES-MMIP exhibits excellent binding affinity and markedly higher selectivity for formononetin over structural analogs (biochanin A, genistein, daidzin) and coexisting interferents (luteolin, resveratrol). The magnetic core-shell structure enables rapid separation within seconds. Under optimized conditions, the DES-MMIP exhibited a high adsorption capacity of 17.22 mg/g for formononetin with an imprinting factor ( IF ) of 5.04. The method showed good linearity over the concentration range of 5–100 μg mL −1 ( r  = 0.9996), with a limit of detection (LOD) of 0.6 μg mL −1 . The recoveries of formononetin from spiked Astragalus extracts ranged from 97.33% to 98.67% with a relative standard deviation (RSD) of 0.67% ( n  = 3). This work provides a convenient, efficient, and green adsorbent for formononetin enrichment and offers a generalizable paradigm for isolating other low-abundance active components from traditional Chinese medicines. Download: Download high-res image (99KB) Download: Download full-size image