Covalent bonding of Schiff base network-1 as a stationary phase for capillary electrochromatography

Covalent organic frameworks (COFs), featuring low densities, high surface areas, and good thermal and chemical stabilities, are gradually attracting interest in the field of analytical chemistry. A type of microporous polymer network material named Schiff base network-1 (SNW-1) was introduced into a capillary column through covalent bonding. The obtained SNW-1-coated capillary column was characterized by thermogravimetric analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. Then, the SNW-1-coated capillary column was successfully utilized for the open-tubular capillary electrochromatography (OT-CEC) separation of sulfonamides, cephalosporins, amino acids and parabens. The fabricated capillary column showed good separation efficiency (Rs > 1.4), stability and reproducibility (relative standard deviation (RSD)