Metal-organic framework composites-based molecularly imprinted polymers functionalized with deep eutectic solvent for selective extraction of Salvianolic acid A from Salvia miltiorrhizae Radix.

Efficient and selective enrichment of Salvianolic acid (SAA) from natural herbs is a promising approach with substantial potential for practical applications. Therefore, SiO@UiO-66@DESs@MIPs was synthesized by using in-situ generated MOF particles (SiO@UiO-66) as the carrier and incorporating deep eutectic solvents (DESs) with good water compatibility as functional monomer. The poly-DESs imprinting layer with rich active sites is uniformly encapsulated onto SiO@UiO-66, facilitating the generation of imprinting sites exclusively on the external surface of SiO@UiO-66@DESs@MIPs, which is conducive to the specific recognition of SAA. This methodology can effectively mitigate the embedding of template molecules, enabling the SiO@UiO-66@DESs@MIPs to inherit the exceptional high surface area of UiO-66, ultimately resulting in an enhancement of their affinity and mass transfer efficiency. DESs can produce multiple binding force with SAA, enhancing the hydrophilicity and recognition ability of SiO@UiO-66@DESs@MIPs. Consequently, SiO@UiO-66@DESs@MIPs demonstrated excellent selectivity (IF=3.79), high adsorption capacity (Q=176.4 mg g), and rapid mass transfer efficiency (t = 60 min) for SAA. Under optimal adsorption conditions, the linear range of this method was determined to be 3.0 μg mL-11.4 mg mL, with a LOD of 0.32 μg mL and a LOQ of 1.07 μg mL. The recovery of SAA from Salvia miltiorrhizae Radix using SPE ranges from 94.4 % to 102.9 %, confirming the high practicality of SiO@UiO-66@DESs@MIPs. Additionally, SiO@UiO-66@DES@MIPs demonstrate remarkable regeneration ability, as it can be reused 9 times without any change in the micromorphology and adsorption performances. These results indicated that SiO@UiO-66@DESs@MIPs represent a valuable imprinted adsorbent for the selective of SAA from Salvia miltiorrhizae Radix.