Monolithic column with polymeric deep eutectic solvent as stationary phase for capillary electrochromatography

A novel monolithic column based on the copolymerization of ethylene dimethacrylate and a deep eutectic solvent (DES), which composed of chlorocholine chloride and itaconic acid, was developed for capillary electrochromatography (CEC). The structure and morphology of the obtained monolithic column was characterized by Fourier transform infrared spectra and scanning electron microscopy, which showed a porous monolithic structure with good permeability. The influence of pH value and acetonitrile content on electroosmotic flow (EOF) of DES-based monolithic column was investigated. The DES-based monolithic column was used as the separation column of CEC and exhibited excellent performance for the separation of neutral compounds, phenols, toluidines, nucleosides, nucleotide bases and alkaloids. The retention mechanism might be attributed to synergistic effect of hydrophobic interaction, hydrogen bond interaction and electronic interaction. The DES-based monolithic column showed good repeatability with relative standard deviations of migration time less than 0.80%, 2.15%, 4.26% and 3.08% for intra-day, inter-day, column-to-column and batch-to-batch, respectively. Thus, organic polymer monolithic columns with DESs as functional monomers are a promising option in chromatographic separation.