Polymeric deep eutectic solvents-functionalized carbon nanotubes: a synergistic buffer additive for enhanced enantioseparation in capillary electrophoresis.

The application of carbon nanotubes (CNTs) in capillary electrophoresis (CE) for chiral separation is often limited by their poor dispersibility, tendency to aggregate, and lack of enantioselectivity. This study reports the preparation of a class of polymeric deep eutectic solvents (PDES) modified hydroxylated carbon nanotube composites (PDES@CNT) via an aqueous solution copolymerization method and their application as pseudostationary phase for chiral separation in CE. The proposed materials were characterized by nuclear magnetic resonance, infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, transmission electron microscopy, and the Tyndall effect. The results demonstrate that the modification of PDES significantly enhances the dispersibility and electrophoretic stability of CNTs in aqueous buffers, effectively improving the issues of CNTs aggregation and separation repeatability. Compared with the single methyl-β-cyclodextrin (M-β-CD) system, the common DESs/M-β-CD systems, and the common DESs@CNTs systems, the PDES@CNTs systems exhibit superior separation performance for some studied model drugs. The potential mechanism of PDES@CNTs for improving separation was discussed through molecular simulation. The PDES@CNTs systems may construct an efficient chiral microenvironment through multiple intermolecular interactions, thereby enhancing enantioselective recognition capability.