Chitosan beads with pendant alpha-cyclodextrin: preparation and inclusion property to nitrophenolates

Highly porous beads having an ability to form inclusion complexes with specific substrates have been synthesized and preliminary experiments for the application to adsorbent for affinity column chromatography and controlled release were carried out. Water-insoluble chitosan beads were synthesized by adding an aqueous acetic acid solution of chitosan into ethanolic aqueous sodium hydroxide and subsequent crosslinking with hexamethylene diisocyanate in N, N-dimethylformamide. The resulting beads were further treated with 2-O-formylmethylalpha-cyclodextrin in the presence of sodium cyanoborohydride in acetate buffer at pH 4.4, giving the cyclodextrin-linked chitosan beads. Their inclusion ability was examined by the use of p-nitrophenol and its analogue as model compounds.