In situ growth preparation of a new chiral covalent triazine framework core-shell microspheres used for HPLC enantioseparation.

The manufacturing of chiral covalent triazine framework core-shell microspheres CC-MP CCTF@SiO composite is reported as stationary phase for HPLC enantioseparation. The CC-MP CCTF@SiO core-shell microspheres were prepared by immobilizing chiral COF CC-MP CCTF constructed using cyanuric chloride and (S)-2-methylpiperazine on the surface of activated SiO through an in-situ growth approach. Various racemates as analytes were separated on the CC-MP CCTF@SiO-packed column. The experimental results indicate that 19 pairs of enantiomers were well separated on the CC-MP CCTF@SiO-packed column, including alcohols, phenols, amines, ketones, and organic acids. Among them, there are 17 pairs of enantiomers that can achieve baseline separation with good peak shapes. Their resolution values on this chiral column are between 0.4 and 5.61. The influences of analyte mass, column temperature, and composition of the mobile phase on the resolution of enantiomers were studied. In addition, the chiral resolution ability of CC-MP CCTF@SiO-packed column was compared with the commercial chiral chromatographic columns (Chiralpak AD-H and Chiralcel OD-H columns) and some CCOF@SiO chiral columns (β-CD-COF@SiO, CTpBD@SiO, and MDI-β-CD-modified COF@SiO). The CC-MP CCTF@SiO-packed column exhibited some unique advantages and can complement these chiral columns in chiral separations. The research results show that the CC-MP CCTF@SiO chiral column offered high column efficiency (e.g., 17680 plates m for ethyl mandelate), low column backpressure (5-9 bar), high enantioselectivity, and excellent chiral resolution ability for HPLC enantioseparation with good stability and reproducibility. The relative standard deviations (RSD) (n = 5) of the retention time, and peak areas by repeated separation of ethyl mandelate are 0.23% and 0.67%, respectively. It demonstrates that the CC-MP CCTF@SiO core-shell microsphere composite has great potential in enantiomeric separation by HPLC.