Monolithic silica columns with chemically bonded β-cyclodextrin as a stationary phase for enantiomer separations of chiral pharmaceuticals

摘要

An enantioselective silica rod type chiral stationary phase (CSP) is presented; a novel combination of the well known enantiomer separation properties of β-cyclodextrin and the unique properties concerning the flow behavior of silica monoliths. Two different synthesis routes are described, and it was found that the in situ modification of a plain silica rod column turned out to be the best. The chromatographic behaviour of the β-cyclodextrin silica rod was studied and compared with a very similar commercially available β-cyclodextrin bonded particulate material (ChiraDex). Even if the amount of β-cyclodextrin bound to the silica rod was only about half of the amount of β-cyclodextrin bound to ChiraDex particles, good resolution s were achieved for a set of chiral test components like Chromakalin, Prominal, Oxazepam, Methadone and some other drugs. By taking advantage of the unique features of the silica rods relating to their flat H/u (Van Deemter) curves, fast enantiomer separations could be demonstrated.