Uniformly sized β-cyclodextrin molecularly imprinted microspheres prepared by a novel surface imprinting technique for ursolic acid

A novel surface imprinting technique was reported to synthesize uniformly sized molecularly imprinted microspheres (MIMs) using ursolic acid (UA) as the template. Three kinds of MIMs were prepared using uniformly sized functionalized poly (glycidyl methacrylate) microspheres (F-P-GMA) as the support matrix. Adsorption experiments indicated the imprinting factor of MIMs-1 prepared with bonded p-cyclodextrin (beta-CD) and acrylamide (AA) in combination was superior to those prepared with bonded P-CD (MIMs-2) or AA (MIMs-3) individually, and the binding isotherm of MIMs-1 was in good agreement with the two-site binding model. The results of chromatographic evaluation indicated that baseline separation could be achieved on MIMs-1 column for UA and oleanolic acid (OA). Compared with NIMs-1 and the traditional reverse phase C18 column, MIMs-1 showed good affinity and efficiency for separation of UA and OA. The results show the possibility for application of MIMs-1 as high performance liquid chromatography (HPLC) stationary phase to separate and determinate UA and OA. MIMs-1 was applied to separate UA from Ilex kudingcha C. J. Tseng extract and good results were obtained, which developed a new adsorbent material to solid-phase extract UA from herbs. (C) 2008 Elsevier B.V. All rights reserved.