β-Cyclodextrin Functionalized Covalent Organic Polymer Monolithic Column for Highly Selective Capillary...

The synthesis of covalent organic polymers (COPs) with abundant active sites remains challenging. To address this, we developed β-cyclodextrin (β-CD) functionalized COPs through a modular synthesis strategy, which was comprehensively characterized and subsequently employed as a stationary phase for capillary electrochromatographic separations. Compared with the unmodified column, the β-CD-functionalized COP monolithic column exhibited better separation performance for analytes spanning a wide range of physicochemical properties, including monosubstituted benzenes, alkylbenzenes, phenols, isomers, and chiral compounds, achieving baseline resolution > 1.5 for all tested compounds and a maximum column efficiency of 35 013 plates m^-1 for chlorobenzene. Experiments and non-covalent interaction analysis indicated that the synergistic effect between the β-CD cavity and aromatic groups enables the β-CD-functionalized COP stationary phase to exhibit multiple interaction modes (e.g., hydrophobic, π …π stacking, and hydrogen bonding), providing a theoretical foundation for the experimental data. Moreover, the column demonstrated good repeatability and stability, with relative standard deviations for intra-day, inter-day, and column-to-column repeatability all below 2.1%. The column was successfully applied to the determination of monosubstituted benzenes in wastewater samples, showing satisfactory linearity (R² ≥ 0.998), which confirms its potential for complex sample analysis.