A Stable, Molecularly Imprinted Porous Hydrogel Membrane via Chemical Cross-Linking for Glyphosate Detection

The stability of molecularly imprinted membranes (MIMs) is a critical factor influencing their reusability and detection performance. To overcome stability limitations, a robust porous imprinted hydrogel membrane (porous PVA/HS-β-CD/Ag/MIPs) was developed by grafting recognition sites onto a porous framework. The membrane was synthesized through a multistep process: (i) A porous hydrogel matrix was formed via freeze-thaw-induced cross-linking between poly(vinyl alcohol) (PVA) and thiolated β-cyclodextrin (HS-β-CD), combined with the use of a pore-forming agent; (ii) the membrane was functionalized as a surface-enhanced Raman scattering (SERS) substrate through in situ reduction of silver ions (from AgNO₃); (iii) glyphosate (GLY)-imprinted polymers were anchored via precipitation polymerization, utilizing HS-β-CD as grafting sites to achieve specific recognition and detection. Morphological and stability analyses demonstrated that the SERS-imprinted porous membrane exhibits high structural integrity, retaining 94.89% of its detection capability after 12 h under continuous water flow. This study introduces a robust covalent anchoring strategy between the imprinting layer and the substrate to form chemical cross-linking, providing an effective pathway for designing high-performance, long-lifespan molecularly imprinted membranes.