An ionic liquid assisted hydrogel functionalized silica stationary phase for mixed-mode liquid chromatography

An ionic liquid assisted hydrogel modified silica was synthesized using a one-pot polymerization and physical coating technique and subsequently applied to mixed-mode liquid chromatography. Analytical techniques, including Fourier transform infrared spectroscopy (FT-IR), x-ray photoelectron spectroscopy (XPS), and elemental analysis, etc., confirmed the successful prepared of this innovative stationary phase. The unique combination of amide, long alkyl chain, and imidazole ring in the hydrogel coating enables the stationary phase to function effectively in hydrophilic/reversed-phase/ion exchange liquid chromatography. Notably, the stationary phase exhibited superior separation performance owing to the synergistic effect of the ionic liquid and hydrogel. This was particularly evident when analyzing various analytes such as organic acids, nucleosides/bases, polycyclic aromatic hydrocarbons (PAHs) and anions. Furthermore, under our operating conditions, an excellent column efficiency of 53642.9 plates/m was achieved for theobromine. In summary, we have proposed a straightforward strategy to enhance the separation performance of hydrogel coatings in liquid chromatography, thereby broadening the potential applications of hydrogels in the field of separation.