Abstract

Chlorogenic acid (CA) is an important natural antioxidant component and holds strong potential for health food and cosmetic applications. In this study, a silica-based photo-responsive molecular imprinting material (PMI-PDA@NH2-SiO2) was designed as a solid-phase extraction (SPE) adsorption filler and applied for the efficient separation of CA in Ficus carica L. Using polydopamine-modified NH2-SiO2 silica as the base, combined with the photo-responsive monomer 4-methacryloyloxyazobenzene (AZO-MAA), a molecular imprinting layer with photo-responsive regulation function was constructed. Under 365 nm ultraviolet light irradiation, the azobenzene group was isomerized to the cis structure, causing the imprint cavity to shrink, thereby enabling controlled release of CA, with complete desorption within 40 min, and a desorption rate of 94.33%. Importantly, the material retained 85.56% of its initial adsorption capacity and 91.38% of its original desorption efficiency after 6 consecutive adsorption/desorption cycles, confirming robust operational stability and reproducibility. PMI-PDA@NH2-SiO2 was applied to the extract of Ficus carica L., achieving an adsorption rate of 92.3% for CA and a desorption rate of 87.27%. Density functional theory (DFT) calculations and NOESY spectroscopic analyses revealed that CA interacted with functional monomers via hydrogen bonding and van der Waals forces. This study advances a green separation strategy for bioactive phytochemicals in complex natural matrices.

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