Selective Separation of Salvianolic Acid B from Salviorrhiza by Surface Imprinted Polymers Based on Metal-Organic Frameworks ZIF-8

Salvianolic acid (SAB) is a natural flavonoid compound possessing significant pharmaceutical value. However, the extraction and purification of SAB from natural products are hindered by the complexity and low concentration of matrix components. In this research, a new surface imprinted polymer with core-shell structure, denoted as ZIF-8@MIPs, was successfully developed using porous metal-organic frameworks (MOF) ZIF-8 as the scaffold. ZIF-8@MIPs exhibited remarkable selective extraction and enrichment of SAB from Salviorrhiza. Series of characterizations and adsorption experiments demonstrated that ZIF-8@MIPs possessed a typical core-shell octahedral structure with a high specific surface area. The resultant high-density imprinted sites allowed the ZIF-8@MIPs to exhibit a high adsorption capacity (46.7 mg/g) and exceptional selectivity (IF = 3.11) for SAB, while achieving adsorption equilibrium within 90 min. Notably, the ZIF-8@MIPs maintained an adsorption capacity of 89.2% for SAB after 7 cycles of adsorption-desorption experiments, indicating good reusability. Furthermore, a solid-phase extraction column was established utilizing the ZIF-8@MIPs as the adsorbent, and the content of SAB in the Salviorrhiza extract was determined by combining this with HPLC. The spiked recovery rate ranged from 87.70 to 92.90%, with RSD of 2.87–3.43%, demonstrating the reliability and reproducibility of this method. In conclusion, the ZIF-8@MIPs developed in this study offer a promising approach for the selective extraction of active flavonoids from natural matrices, with potential application in application prospects.