Magnetic surface molecularly imprinted polymers for efficient selective recognition and targeted separation of daidzein

Daidzein, a naturally occurring source of estrogenic isoflavones, holds significant promise for various applications in food and drug development. Therefore, to realize efficient and precise daidzein separation, we synthesized a magnetic surface molecularly imprinted polymer (Daidzein/SMIPs) via free radical-initiated polymerization via magnetic surface molecular imprinting technology. The adsorption capacity of the Daidzein/SMIPs for daidzein at an initial concentration of 300 µg·mL⁻¹ reached 18.44 mg·g⁻¹ within 20 min at 298 K. Even after nine adsorption-desorption cycles, the adsorption capacity remained high (81.42% of the initial adsorption capacity). Furthermore, the Daidzein/SMIPs exhibited exceptional selectivity for daidzein, with an imprinting factor of 1.83 and selection coefficients (K) of 1.94, 2.43, 2.63, and 1.66 for structurally similar competing molecules such as naringin, quercetin, diosmetin, and alizarin, respectively. In practical applications, isolating daidzein from real daidzein tablets using the Daidzein/SMIPs resulted in high recoveries of 88.09 to 98.12% with excellent precision (relative standard deviation of 1.51–1.02%). Therefore, the constructed Daidzein/SMIPs feature immense potential for targeted daidzein isolation applications.