Nonaqueous capillary electrophoretic enantioseparation of water insoluble Tröger's base derivatives using β-cyclodextrin as chiral selector

Racemic mixtures of six Tröger's base derivatives were separated by chiral nonaqueous capillary electrophoresis. The separation protocol was optimized first for suitable solvents. Then the applicability of various salts dissolved in organic solvents and their mixtures was evaluated. As chiral selectors β-cyclodextrin and heptakis(2,6-di-O-methyl)-β-cyclodextrin at various concentrations were used. The best enantioselectivity for the studied analytes was obtained utilizing formamide as organic nonaqueous solvent containing a mixture of sodium citrate and tris(hydroxymethyl)aminomethane acetate as electrolytes, and β-cyclodextrin as chiral additive. The experimental results demonstrated the feasibility of nonaqueous capillary electrophoresis for enantioseparation of Tröger's base derivatives. This technique represents a suitable alternative to more commonly used capillary electrophoresis in aqueous environment.