Facile preparation of polysaccharide-coated capillaries using a room temperature ionic liquid for chiral separations

In this study, the dissolution of polysaccharides into an ionic liquid was investigated and applied as a coating onto the capillary walls of a fused-silica capillary in open-tubular CEC. The coating was evaluated by examining the chiral separation of two analytes (thiopental, sotalol) with three cellulose derivatives (cellulose acetate, cellulose acetate phthalate, and cellulose acetate butyrate). Baseline separation of thiopental enantiomers was achieved by use of each polysaccharide coating (Rs: 7.0, 8.1, 7.1), while sotalol provided partial resolution (Rs: 0.7, 1.0, 0.9). In addition, reproducibility of the cellulose-coated capillaries was evaluated by estimating the run-to-run and capillary-to-capillary RSD values of the EOF. Both stability and reproducibility were very good with RSD values of less than 7%.