Chiral covalent triazine framework CC-DMP CCTF@SiO2 core–shell microspheres used for HPLC enantioseparation

Abstract

Chiral covalent triazine frameworks (CCTFs), as emerging chiral organic porous polymer materials, have many special properties, such as being rich in nitrogen, having a large surface area, adjustable porosity, and high chemical stability, etc., making them an attractive separation medium for HPLC enantioseparation. Herein, a novel chiral core–shell composite CC-DMP CCTF@SiO₂ with uniform spherical particles was synthesized by an in situ growth method. The prepared chiral core–shell microspheres CC-DMP CCTF@SiO₂ were adopted to resolve chiral compounds by HPLC. The results showed that the CC-DMP CCTF@SiO₂ packed column exhibited good separation performance and high column efficiency (e.g., 17 580 plates m⁻¹ for 4-methylbenzhydrol) under a low column back pressure (5–9 bar) for HPLC separation of different chiral compounds such as alcohols, amines, ketones, and so on. Among them, the resolution values of naringenin and 1-phenyl-1,2-ethanediol were 4.24 and 4.09, respectively. Comparing the chiral recognition capacity of the CC-DMP CCTF@SiO₂ packed column with those of commercial Chiralpak AD-H and the previously reported CCOFs@SiO₂ (CTpBD@SiO₂, β-CD-COF@SiO₂) columns, the CC-DMP CCTF@SiO₂ packed column can be complementary to the Chiralpak AD-H and CCOFs@SiO₂ columns. The effects of the injection amount and column temperature on the separation process were also studied. The CC-DMP CCTF@SiO₂ packed column exhibited good reproducibility and stability after multiple injections. The relative standard deviations (RSD_S) of the retention time and peak area for repeated separation of 4-methylbenzhydrol (n = 5) were 0.45% and 0.87%, respectively. This work suggests that the chiral CC-DMP CCTF@SiO₂ core–shell microsphere composite has a promising application as a novel CSP material in HPLC.