[Preparation of a novel polyhydroxy silica stationary phase and application in the separation of alginate oligosaccharides].

Hyperbranched polyglycerols （HPG） represent an emerging class of dendritic polyethers characterized by a highly branched， three-dimensional architecture and a multitude of terminal hydroxyl groups. This distinctive structural configuration confers exceptional hydrophilicity， biocompatibility， and a high density of modifiable surface functionalities， thus establishing HPG as highly promising materials for the development of advanced chromatographic stationary phases. Their application is particularly relevant for the separation of polar and hydrophilic analytes， which has long posed a significant challenge in conventional reversed-phase liquid chromatography. The integration of such hyperbranched polymers with robust inorganic substrates， such as silica gel， has recently gained traction as a sophisticated materials strategy. This approach synergistically combines the superior mechanical strength and pressure resistance of the inorganic matrix with the rich surface chemistry and tunable hydrophilicity of the polymer， thereby addressing critical limitations of traditional stationary phases in hydrophilic interaction liquid chromatography （HILIC） applications.In the present study， a novel HILIC stationary phase， designated HPG-Sil 3， was synthesized through the in-situ ring-opening polymerization of glycidol monomers from the surface of aminopropyl-functionalized silica microparticles. The synthesis commenced with a meticulous silanization step to graft （3-aminopropyl）triethoxysilane （APTES） onto the silica surface， thereby introducing a uniform layer of primary amine groups. These amine functionalities served as initiation sites for the subsequent grafting-from polymerization， ensuring the formation of a covalently anchored， robust HPG layer. This covalent immobilization strategy is critical for mitigating stationary phase degradation and polymer leaching under prolonged chromatographic use， thereby guaranteeing long-term operational stability. The successful fabrication of the HPG-Sil 3 material and its physicochemical properties were thoroughly characterized using a suite of analytical techniques. Elemental analysis indicated a substantial increase in carbon and hydrogen content post-modification， providing quantitative evidence of organic polymer grafting. Fourier-transform infrared （FTIR） spectroscopy further corroborated this result， revealing signature absorption bands associated with the stretching vibrations of O-H and C-O-C ether linkages， which are characteristic of the HPG polyether structure. Thermogravimetric analysis （TGA） demonstrated the material's excellent thermal resilience， with the onset of HPG decomposition occurring above 200 ℃， a temperature window far exceeding the operational range of typical HILIC analyses. Textural properties， evaluated via nitrogen physisorption， showed a predictable decrease in specific surface area and pore volume relative to the unmodified silica substrate. This reduction is attributed to the partial filling of the mesoporous silica network by the grafted HPG chains. Importantly， the material retained a sufficiently open porous structure to facilitate efficient mass transfer of analytes during chromatographic runs. To systematically investigate the chromatographic behavior and retention mechanism of the HPG-Sil 3 phase， a set of model polar compounds， including thymine， uracil， hypoxanthine， and adenosine， was selected. The influence of critical mobile phase parameters on the analyte retention factor （