A novel one-pot strategy to prepare β-cyclodextrin functionalized capillary monoliths for enantioseparation of basic drugs

With native beta-cyclodextrin (beta-CD) added into the polymerization mixture directly, a novel, convenient and low-cost one-pot strategy was developed to prepare the beta-CD functionalized organic polymer monolithic capillary column. Diazabicyclo[5.4.0]undec-7-ene (DBU) as a basic catalyst for the ring opening reaction between beta-CD and glycidyl methacrylate (GMA) was introduced into the polymerization system for the first time. Thereby, two consecutive reactions namely the in situ methacrylation of beta-CD and copolymerization reaction can be achieved in one pot. The preparation conditions including the type and composition of porogens, the ratio of functional monomer to crosslinker and amount of 2-acrylamido-2-methyl propane sulfonic acid (AMPS) were optimized. The specific surface area and morphology of the prepared monolith were characterized using scanning electron microscopy (SEM) and nitrogen adsorption analysis, respectively. Raman spectroscopy and nuclear magnetic resonance (NMR) spectroscopy confirmed that beta-CD was covalently bonded onto the monolith successfully. Then, the monolithic column was applied to enantioseparation of six basic drugs in capillary electrochromatography (CEC). Under the optimal conditions, tropicamide, homatropine, homatropine methylbromide, brompheniramine, chlorpheniramine and clorprenaline were all totally separated with the resolution (Rs) values of 2.84, 4.70, 4.61, 3.01, 2.57 and 2.33, respectively. Furthermore, the column demonstrated satisfactory stability and repeatability of retention time and enantioselectivity using homatropine as model analyte.