Fabrication of molecularly imprinted polymers with tunable adsorption capability based on solvent-responsive cross-linker

Molecularly imprinted materials with switchable adsorption capability based on solvent-responsive cross-linker. [Display omitted] •Solvent-responsive molecularly imprinted polymers (S-MIPs) were developed.•The adsorption behavior of S-MIPs was regulated by solvent composition.•S-MIPs were successfully employed to solvent-regulated separation of BPA in human urine. The fabrication of facile and versatile adsorbents with switchable adsorption performance based on molecularly imprinting polymers is of great interest although still very challenging. Herein, a dynamic solvent-responsive poly (ethylene glycol) unit-containing chain was introduced as cross-linker to prepare solvent-responsive molecularly imprinted polymers (S-MIPs) by free radical polymerization. Acryloyl-modified beta-cyclodextrin was used as functional monomer, methacrylic acid as co-functional monomer and bisphenol A (BPA) as model template. BPA can be tightly adsorbed in recognition sites by host-guest interaction and hydrogen binding. Solvent-responsiveness of S-MIPs was investigated. Templates can be easily bound into the recognition cavity in 25% methanol aqueous solution with binding capacity of 21.36 mg/g while completely release in 100% methanol following the de-swelling of the imprinting cavity. Binding experiments demonstrated that S-MIPs displayed appreciable recognition capability and selectivity toward BPA in 25% methanol solution, well lining with Langmuir isothermal model and pseudo-second-order model. The proposed S-MIPs were successfully applied for the direct enrichment of BPA from human urine without protein pre-deposition process. Under the optimum conditions, the S-MIPs exhibited satisfactory recoveries ranging from 77.3% to 87.8% (spiked level from 40 μg/L to 800 μg/L), indicating excellent applicability for specific analytes removal from urine samples. This simple synthetic strategy provides an efficient route to synthesize the new intelligent materials for sample analysis in complicated biological matrixes.