Capillary electrochromatography using knitted aromatic polymer as the stationary phase for the separation of small biomolecules and drugs

Hypercrosslinked polymers (HCPs) are currently receiving great attention due to their unique characteristics and potential uses in diverse areas. However, the field of HCPs for open-tubular capillary electrochromatography (OT-CEC) separations has not been explored. Here, a knitted aromatic polymer (KAP) was in-situ grown on the inner wall of the capillary column for OT-CEC for the first time. The silylating reagent containing phenyl was served as monomer, immobilized on the inner wall of the capillary column, and then KAPs-modified capillary column was prepared through in-situ hypercrosslinldng reaction. The surface structure and morphology of KAPs-modified capillary column was characterized by Fourier transform infrared spectra (FT-IR) and scanning electron microscopy (SEM). The prepared capillary columns showed good separation performance for neutral compounds, small biomolecules, such as nucleosides, amino acids, small peptides, and non-steroidal anti-inflammatory drugs, sulfa drugs. In addition, the KAPs-modified capillaries showed good reproducibility, with relative standard deviations for infra-day, inter-day and column-to-column runs less than 1.59%, 2.55%, and 5.19% respectively. The strategy of in-situ immobilization of KAPs provides a new approach for the application of the material in the analytical fields.