Polyethyleneimine hydrogel-silica composite with embedded silver nanoparticles as a multifunctional stationary phase...

The development of chromatographic stationary phases remains a persistent focus of scientific inquiry, as their functions and properties directly determine separation efficiency and application scope. Although hydrogel-based stationary phases exhibit prominent advantages such as customizable functionalities and multiple interaction sites, their inherent defects of poor mechanical strength and significant swelling tendency severely restrict their practical implementation in HPLC analysis. Thus, developing novel hydrogel-based stationary phases with excellent mechanical stability and efficient separation capability has become a key demand in this field. In this study, polyethyleneimine (PEI) hydrogel and silver nanoparticles (AgNPs) were successively anchored onto the silica microspheres to prepare a designed AgNPs/PEI nanocomposite hydrogel-functionalized silica stationary phase (AgNPs/PEI hydrogel@SiO₂). By virtue of the strong coordination between the high-density amino groups in PEI and Ag⁺, stable anchoring of metal precursors and uniform dispersion of AgNPs were achieved, while the cross-linking degree of hydrogel was enhanced, simultaneously solving the problems of insufficient mechanical properties of hydrogel-based stationary phases. The AgNPs/PEI hydrogel@SiO₂ stationary phase integrated multiple separation mechanisms and successfully achieved baseline separation of positional isomers, vitamins, nucleosides, and sulfonamides. Notably, the sulfonamides exhibited a typical mixed-mode chromatographic behavior, demonstrating superior retention strength and selectivity on the AgNPs/PEI hydrogel@SiO₂ column compared to the commercial XAmide column. Ultimately, the AgNPs/PEI hydrogel@SiO₂ was successfully applied to the detection of sulfonamides in lotion and lake water, confirming its reliability and accuracy for real sample analysis. This work introduces an innovative design concept for multifunctional HPLC stationary phases, overcoming the limitations of traditional hydrogel-based materials. With its excellent mechanical stability, versatile separation capabilities, and adaptability to complex samples, the AgNPs/PEI nanocomposite hydrogel offers an efficient solution for analyzing intricate systems, highlighting its significant scientific value and broad application potential in HPLC analysis.