Photochemical immobilization of cellulose tris(3-chloro-5-methylphenylcarbamate) on silica and its use for separation of enantiomers in high-performance liquid chromatography.

Author: Tamar Khatiashvili
Keywords: chromatography, chiral stationary phase, mobile phase, enantiomers, thermodynamics
Annotation:

Analytical and preparative separation of enantiomers is considered as the most difficult problem in separation science for many years due to identical properties of enantiomers in achiral environment, although in chiral environment their properties are different. Only since 1980s chiral columns for high-performance liquid chromatographic (HPLC) separation of enantiomers became commercially available. Among all chiral stationary phases (CSP) available today for HPLC separation of enantiomers polysaccharide-based chiral columns are most widely used. Polysaccharide-based CSPs are commonly prepared by physical coating of polysaccharide derivative onto the surface of silica. This is a fast method that does not require pre-activation of silica or polysaccharide derivative. As for covalently immobilized CSPs, the main mechanism of immobilization is interconnection of polysaccharide chains. The advantage of this method is that immobilized chiral stationary phases are stable and compatible with various mobile phase composition. The major research goal of the present thesis is photochemical immobilization of cellulose tris(3-chloro-5-methylphenylcarbamate) on silica and its comparison with adsorbent prepared by coating cellulose tris(3-chloro-5-methylphenylcarbamate) on silica for separation of enantiomers in high-performance liquid chromatography. We also compared separation of enantiomers in different mobile phases, such as methanol, acetonitrile and mixture of n-hexane and isopropanol with various ratios. In the frames of the present thesis we also studied the thermodynamics of enantioseparations on these newly prepared materials.