A monolithic azacalix[4]pyridine column for high-resolution and high-efficiency pressurized capillary electrochromatographic separation

Herein, a highly stable (NAllyl)4-bridged alyzacalix[4]pyridine monolithic column (nAC4P@capillary) was fabricated by copolymerizing nAC4P with GMA and EDMA into a stationary phase through a simple olefin addition reaction. The physicochemical properties of the prepared materials were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy dispersive X-ray (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and elemental analysis (EA). A wide range of analytes with various properties was well separated and demonstrated the synergistic effect of the various interaction sites. The maximum column efficiencies (Nmax) for all the analytes reached 62,368 plates/m, and the relative standard deviations (RSDs) of the daily retention times of alkylbenzenes, measured over six months were all lower than 5.63%. Non-covalent interaction analysis reveals that nAC4P@capillary can effectively combine the advantages of electronic configurations, π-π interactions, CH-π interactions, O–H…N hydrogen bonds and lone pair-π interactions, providing excellent prospects for high-performance chromatographic separation.