Construction and application of mixed-mode stationary phase based on ionic liquid from rosin acid.

The development of innovative functional materials derived from renewable biomass resources has attracted considerable interest. This strategy not only reduces dependence on petrochemical raw materials during production, thereby lowering carbon emissions and alleviating environmental pollution, but also increases the value-added potential, contributing to the advancement of associated agricultural and forestry industries. In this work, a rosin-based ionic liquid modified silica (Sil-VDA) was synthesized through a thiol-ene click reaction and subsequently applied to mixed-mode liquid chromatography. The successful synthesis of the novel stationary phase was confirmed through various analytical techniques. The presence of imidazolium, carbonyl group, and hydrogenated phenanthrene rings on the surface of Sil-VDA facilitates its application in hydrophilic/ion-exchange/reversed-phase liquid chromatography, utilizing a combination of retention mechanisms such as hydrophilic, hydrophobic, hydrogen bonding, π-π interactions, and electrostatic interactions. Remarkably, the stationary phase exhibited superior separation performance due to the synergistic effect of these multiple retention mechanisms, which was especially evident in the analysis of various analytes, including polycyclic aromatic hydrocarbons (PAHs), alkylbenzenes, nucleosides/bases, sulfonamides, flavonoids, organic acids, organic bases, and anions. Under the experimental conditions, the Sil-VDA column demonstrated excellent efficiency, achieving 67,993 plates·m-1 for cytosine. Comparative analysis with optimized chromatographic conditions for commercial C18 and NH2 columns further highlighted the distinct advantages of this new stationary phase in the selective separation of mixed analytes. In conclusion, this study presents a novel and effective strategy for the utilization of rosin in liquid chromatographic separation materials, showcasing mixed-mode separation performance and high selectivity, thus broadening the potential applications of rosin and rosin-based ionic liquids in mixed-mode separation research.