Combination of flow injection with capillary electrophoresis. Part 2. Chiral separation of intermediate enantiomers in chloramphenicol synthesis

The combined flow injection (FI)-capillary electrophoresis (FI-CE) system described in Part I of this series was developed for achieving chiral separation of intermediate racemates in the synthesis of chloramphenicol. Hydroxypropyl-β-cyclodextrin, β-cyclodextrin and heptakis-(2,2-di-o-methyl)-β-cyclodextrin were employed as chiral selectors in the separation buffers. Baseline resolution of enantiomers of the rac-threo bases 2-amino-1-(p-nitrophenyl-1,3-propanediol) was achieved using the combined system demonstrating significantly improved precision and sample throughput compared to conventional CE with manual electrokinetic sample introduction, while achieving similar resolution and column efficiencies. A series of samples (the rac-threo bases) was injected continuously without current interruption, achieving sample throughputs at least a factor of five higher than conventional CE sample introduction.