Teicoplanin-cyclodextrin bilayer chiral stationary phase boosts chiral separation of native amino acids

Abstract

Separating enantiomers is crucial for advancing scientific research. Teicoplanin-based columns exhibit unique advantages in the chiral separation of native amino acids, and its further improvement for better separation performance is valuable. This work reported double-layer bridged columns, in which different amounts of cyclodextrin (CD) were directly bridged onto teicoplanin (TK) molecules on chiral stationary phase (TK CSP) to synthesize TK-CD-2 CSP and TK-CD-6 CSP. Additionally, a column with the two chiral selectors (TK and CD) arranged in a single layer on the silica gel surface (TK+CD CSP) was synthesized, which served as a control group. The results revealed TK-CD-6 CSP had better chiral separation ability of native amino acids and wider range of separable chiral molecules than TK, TK+CD, TK-CD-2 CSPs. The possible mechanism is the dual-layer structure of the column (TK-CD-6 CSP) effectively reduces the competition between different chiral selectors and provides more chiral recognition sites, which enhances the separation ability and achieves broad-spectrum chiral separation. This work offers valuable inspirations for enhancing the chiral separation ability of teicoplanin-based columns and developing liquid chromatographic strategy with separation diversity.