Enantiomer separation by capillary electrochromatography on a cyclodextrin-modified monolith.
A chiral monolithic stationary phase was prepared by packing a capillary with bare porous silica and sintering the silica bed at high temperature. The resulting silica monolith was polymer-coated with Chirasil-Dex, a permethylated beta-cyclodextrin covalently linked via an octamethylene spacer to dimethylpolysiloxane. Subsequently, Chirasil-Dex was thermally immobilized on the silica support and a chiral monolith of very high stability (30 kV, more than 400 bar pressure) was obtained. The enantiomer separation of various chiral compounds by monolithic (rod) capillary electrochromatography (rod-CEC) was feasible. This method was compared with capillary liquid chromatography (LC) in a single-column mode using unified equipment. About two to three times higher efficiency was found in the rod-CEC mode as compared to rod-LC. The influence of pressure-driven flow support on efficiency, resolution, elution time and baseline stability was investigated. The amount and nature of organic modifier strongly influences efficiency and resolution.
Wistuba
D
D
Institute of Organic Chemistry, University of Tübingen, Germany. dorothee.wistuba@uni-tuebingen.de
Schurig
V
V
D001463:Barbiturates / Q000737:chemistry* / Q000302:isolation & purification; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D003505:Cyclodextrins / Q000737:chemistry; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods; D006591:Hexobarbital / Q000737:chemistry* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D012833:Siloxanes / Q000737:chemistry; D013237:Stereoisomerism
D001463:Barbiturates; D003505:Cyclodextrins; D012833:Siloxanes; C090733:Chirasil-Dex; D006591:Hexobarbital