Using self-polymerization synthesis of boronate-affinity hollow stannic oxide based fragment template molecularly imprinted polymers for the selective recognition of polyphenols.

In this work, the boronate-affinity hollow stannic oxide based fragment template molecularly imprinted polymers (Bh@SnO₂-FMIPs) were fabricated successfully. Polystyrene was used as sacrificial support, SnO₂ was selected as inorganic matrix, surface imprinting using catechol as fragment template and 4-vinylphenylboronic acid as boronate-affinity functional monomer. A thin layer of poly 2-anilinoethanol (2-AE) was formed to coat the boronate-affinity hollow SnO₂ surface through self-polymerization, it has strong hydrophilicity and limited residual boric acid content, avoiding non-specific binding. The hollow structure could bind to target molecules effectively and facilitate the removal of template molecules. The Bh@SnO₂-FMIPs were used to extract three cis-diol polyphenols containing catechin, chlorogenic acid, and caffeic acid in tea and juice samples. Combination with seven characterizations of the material confirmed the successful preparation. Effecting the imprinting conditions and extraction efficiency parameters were optimized separately. Selective and competitive adsorption experiments indicated that the materials could specific recognition polyphenols. Using solid phase extraction and high performance liquid chromatography method, the detection limits were 0.005-0.046 μg mL^-1 and the recoveries were between 82.3-104.3%. The improved adsorption performance may be assigned to the synergistic effects among boronate-affinity, hollow SnO₂, and 2-AE self-polymerization. It may enhance binding cavities, hydrophilicity, biocompatibility of adsorbent material, and prevent the aggregation of Sn during the preparation processes.