Cellulases from the fungi Phanerochaete chrysosporium and Trichoderma reesei as chiral selectors in capillary electrophoresis: Applications with displacer plugs and sample preconcentration

The cellulases CBH 58 from the fungus Phanerochaete chrysosporium and CBH I from the fungus Trichoderma reesei were compared as chiral selectors in ca pillary electrophoresis (CE) applying the partial filling technique. Amines , e.g., norephedrine, two bambuterol analogs, as well as acids, e.g., di-p- toluoyl tartaric acid and dibenzoyl tartaric acid, which could not be enant ioseparated in the liquid chromatographic use of the selectors, could be se parated in the corresponding CE experiments. Due to the very high enantiose lectivities, terbutaline, alprenolol and propranolol could be completely en antioresolved with selector plugs shorter than the sample plugs. The affini ty of propranolol to CBH 58 was so high at pH 7.0 that neither of the enant iomers reached the detector; therefore, a plug of the displacing disacchari de cellobiose was injected after the sample to elute the propranolol enanti omers. The enantiomers could also be made to leave the capillary at opposit e ends, thereby causing an infinite enantioresolution. A new preconcentrati on technique was introduced, which takes advantage of the very high affinit y of propranolol to CBH 58 and the eluting ability of cellobiose. A 12.5 cm long plug of rac-propranolol could be preconcentrated and enantioseparated in a single procedure.