Homochiral iron-based γ-cyclodextrin metal-organic framework for stereoisomer separation in the open tubular capillary electrochromatography

Metal organic frameworks (MOFs), as a novel separation mediums, have in recent years attracted wide consideration in capillary electrochromatography (CEC). However, the instability of frameworks limited the application of the MOF-based chiral separation capillary. Herein, Iron-based gamma-cyclodextrin metal-organic framework (Fe-CD-MOF) with mesoporous was developed as the chiral stationary phase in open tubular capillary electrochromatography column (OT-CEC) for the stereoisomer separation of fourteen chiral drugs and one chiral alcohol. The capillary column with MOF coating exhibited the best performance (resolution value: 17.07) for anisodamine in any MOF-based capillary column that has never been reported. Moreover, the effect of pH, buffer concentration, and methanol content has been investigated. The novel coated capillary was also applied for the quantitative analysis of a real sample. The Fe-CD-MOF coated capillary showed outstanding repeatability and stability, with the satisfactory relative standard deviations (RSDs) for intra-day, inter-day, and column-to column. Finally, the enantioseparation mechanism of the Fe-CD-MOF coated capillary was evaluated by adsorption kinetic experiments. In summary, this work indicated the novel and renewable Fe-CD-MOF was a potential chiral stationary phase in CEC chiral separation.

Automated summary

Metal organic frameworks (MOFs) have attracted wide attention as a novel separation medium in capillary electrochromatography (CEC). In this study, a mesoporous Iron-based gamma-cyclodextrin metal-organic framework (Fe-CD-MOF) was developed as the chiral stationary phase in an open tubular CEC column. The Fe-CD-MOF coated capillary showed excellent performance for the separation of fourteen chiral drugs and one chiral alcohol. The coated capillary demonstrated outstanding stability and repeatability, making it a potential chiral stationary phase for CEC chiral separation.