Preparation and application of phenylboronic acid and ionic liquid functionalized silica stationary phase for HILIC/RPLC/IEC mixed mode chromatograph.

BACKGROUND

HPLC is one of the most widely used and versatile separation techniques in analytical science. The development of novel stationary phases is crucial for improving analytical performance, and mixed-mode stationary phases have attracted considerable attention due to their multiple interaction mechanisms. Ionic liquids, with high thermal and chemical stability, good conductivity, and excellent solvation ability, serve as an ideal tool for enabling and enhancing MMC. The combination of phenylboronic acid with ionic liquids can introduce multiple interactions, showing substantial potential for the development of mixed-mode stationary phases.

RESULTS

In this study, phenylboronic acid and ionic liquid were immobilized onto silica to design a novel HPLC stationary phase (Sil-PBA-IM) featuring HILIC/RPLC/IEC mixed mode separation. This stationary phase demonstrated excellent column efficiency (91000 plates/m) and reproducibility (RSD <0.38%). Structural characterization of the stationary phase was performed, and its retention mechanism was investigated by varying chromatographic conditions. Separations of hydrophilic compounds, hydrophobic compounds, organic acids, inorganic salts and dihydroxybenzene isomers were conducted under different chromatographic conditions, with Sil-PBA-IM exhibiting outstanding separation performance. Furthermore, Sil-PBA-IM was successfully applied to the detection and quantitative analysis of puerarin in cold medicine, as well as vitamin B1 and nicotinamide in health supplements, which holds significant importance for drug quality regulation.

SIGNIFICANCE: By combining phenylboronic acid with ionic liquids for the preparation of chromatographic stationary phases, the results demonstrated excellent separation capabilities for various types of analytes in MMC, along with specific recognition ability for diol compounds. The advantages of the two functional monomers were successfully integrated, providing a new strategy for the development of high-performance mixed-mode chromatographic stationary phases in further research.