The preparation of a core–shell stationary phase by the in situ polymerization of a hydrophilic polymer on the surface of silica and its chromatographic performance

Using N-isopropylacrylamide (NIPAM) as a monomer, a core–shell material was successfully prepared via in situ polymerization on the surface of silica microspheres (named NIPAM@Sil), which acts as a hydrophilic interaction chromatography (HILIC) stationary phase. A method for the in situ polymerization of polymer monomers on a silica surface has been developed. It was shown using scanning electron microscopy (SEM) that NIPAM is evenly distributed on the surface of the silica. The synthesized NIPAM@Sil possesses a polar acylamino group arising from the polymerization of NIPAM. As demonstrated by the hydrophilicity, NIPAM@Sil showed excellent HILIC performance for the separation of hydrophilic compounds. This method provides a simple approach for the preparation of a polymer coated silica core–shell stationary phase.