A chiral metal-organic framework synthesized by the mixture of chiral and non-chiral organic ligands for enantioseparation of drugs by open-tubular capillary electrochromatography

•A chiral metal-organic framework was synthesized by chiral and non-chiral ligands.•Five racemic drugs were separated well by capillary electrochromatography.•The mechanism of enantioseparation was studied in depth by several experiments. A chiral metal-organic framework L-Histidine-Zeolitic imidazolate framework-67 (L-His-ZIF-67) was synthesized by the mixture of chiral organic ligand L-histidine and non-chiral organic ligand 2-methylimidazole directly, and to the author's knowledge, the chiral L-His-ZIF-67 coated capillary column we prepared has still not been reported to date in the field of capillary electrophoresis. This chiral metal-organic frameworks material was used as the chiral stationary phase for enantioseparation of drugs by open-tubular capillary electrochromatography. The separation conditions such as pH value, buffer concentration and proportion of organic modifier were optimized. Under optimal conditions, the established enantioseparation system achieved good separation effect, and the resolution of five chiral drugs: esmolol (7.93), nefopam (3.03), salbutamol (2.42), scopolamine (1.08) and sotalol (0.81). In addition, the chiral recognition mechanism of L-His-ZIF-67 was elucidated by a series of mechanism experiments, and the specific interaction force was preliminarily speculated.