Synthesis and evaluation of fosfomycin group end-capped packing materials for hydrophilic interaction liquid...

Hydrophilic interaction liquid chromatography (HILIC) plays an important role in the analysis of compounds having high polarity. In this study, fosfomycin (F) was chosen as a new end-capping reagent, owing to the facile hydrolysis reaction of its epoxy group. Zirconia coated silica (ZrO₂/SiO₂) materials having good chemical and physical stability were prepared. D-glucose-6-phosphate (G) and D-fructose1,6-bisphosphate (FDP) were modified onto the inner and outer surfaces of the ZrO₂/SiO₂ microbeads. The new end-capping reagent (F) was then bonded onto the surface of the modified material through Lewis acid-base interactions. The properties (morphology, Zr content, pore size, pore volume, and carbon content) of the stationary phases (SPs) were characterized. Finally, the resulting end-capped SPs were employed to separate alkaloids and benzoic acids. Multiple interactions, including HILIC, electrostatic repulsion, ion exchange and hydrogen bonding, contributed to the retention of the analytes on the SPs. On the F-FDP-ZrO₂/SiO₂ column, a theoretical plate number of 31,700 plates/m and an asymmetry factor of 1.63 were achieved for berberine, exhibiting good chromatographic performance. Furthermore, the FDP-ZrO₂/SiO₂ column showed good acid-base stability and good potential for the analysis of benzoic acid in Sprite and ginsenoside separations. Thus, the results indicated the significant potential of using F as an end-capping reagent.