Abstract: Quercetin is one of the abundant and cheap flavonoids in herbs. In this paper, quercetin was first chemically bonded to silica gel. A natural ligand quercetin-bonded silica gel stationary phase(QUSP) was obtained by using γ[(2,3)-glycidyloxypropyl trimethoxysilane(KH-560) as a coupling agent.  Its chemical structure was characterized by infrared spectrometry, thermogravimetric analysis, elemental analysis and 13C solid-state nuclear magnetic resonance(NMR). The amount of bonded quercetin was determined to be about 1.39 mmol/g. The reversed-phase property of QUSP based on hydrophobic interaction was first evaluated on high-performance liquid chromatography. The separation abilities of new stationary phase for different polar aromatic compounds were systematically studied by using basic and acidic solutes with different structures as probes. Some retention mechanism in the above separations was also discussed. The results showed that the novel quercetin-boned stationary phase exhibited high separation selectivity for polar compounds, including pyridines, aromatic amines, phenols, benzoic acids, and flavonoids. The baseline separations of the above species were easily achieved by using only simple methanol or acetonitrile water as the mobile phases without fine adjustment of pH in isocratic mode. This is because besides the hydrophobic C6-C3-C6 skeleton, the quercetin ligand QUSP can also provide various active sites for polar solutes, such as hydrogen bonding, dipole-dipole, π-π and charge transfer interactions, in which the synergic interactions could improve separation selectivity, especially for the ionized acidic and basic compounds.

Key words: high-performance liquid chromatography, quercetin-bonded stationary phase, natural ligand, evaluation of chromatographic property, separation mechanism