Cyclodextrin‐NH‐MIL‐53 open tubular stationary phase for capillary electrochromatography enantioseparation

Abstract

A novel chiral group functionalized metal‐organic framework, Cyclodextrin‐NH‐MIL‐53, was synthesized and modified on the inner wall of a capillary column via a post‐synthetic process. The prepared chiral metal‐organic framework was utilized as a chiral capillary stationary phase and used in an open‐tubular capillary electrochromatography method to enantioseparate several racemic amino acids. Excellent enantioseparation of five pairs of enantiomers was obtained in this chiral separation system (Resolutions of D/L‐Alanine = 16.844, D/L‐Cysteine = 3.617, D/L‐Histidine = 9.513, D/L‐Phenylalanine = 8.133, and D/L‐Tryptophan = 2.778). The prepared Cyclodextrin‐NH‐MIL‐53 and the Cyclodextrin‐NH‐MIL‐53‐based capillary columns were characterized by scanning electron microscopy, X‐ray diffraction, Fourie‐transform infrared spectroscopy, and circular dichroism. The chiral capillary electrochromatography conditions, such as separation conditions, amount of Cyclodextrin‐NH‐MIL‐53, and electroosmotic flow, were optimized. This research is estimated to present a novel insight and method for the design and use of metal‐organic framework‐based capillaries for enantioseparation.