Silica grafted with silanized carbon dots as a nano-on-micro packing material with enhanced hydrophilic selectivity

Carbon dots derivatized from N-(β-aminoethyl)-γ-aminopropyl-methyldimethoxysilane (AEAPMS) were coated onto silica microparticles. These particles (Sil-CDs) are shown to be an excellent stationary phase for use in hydrophilic interaction chromatography. Analytes including sulfonamides, nucleosides and bases, flavones and amino acids can be well separated on this stationary phase. Compared to a silica stationary phase functionalized with AEAPMS only, the Sil-CDs show enhanced separation performance. The selectivity factors of three nucleosides and bases (1.02–1.09) and four sulfonamides (1.04–1.11) on AEAPMS functionalized silica stationary phase were improved to 1.10–1.20 and 1.13–1.15 respectively on Sil-CDs stationary phase. This is attributed to the higher number of surface functional groups due to the introduction of carbon dots. The successful application of the Sil-CDs stationary phase highlights the potential of carbon dots as a modified material in chromatography. Schematic presentation of the preparation of silanized carbon dots coated onto silica microparticles. The material represents a new stationary phase for hydrophilic interaction chromatography. It shows improved separation performance compared to a silane-only functionalized silica stationary phase.