Rhein was used as the raw material and γ-aminopropyltriethoxy silane (KH-550) as the coupling agent to simply prepare a new carboxy bonded silica gel (RBSP), which could be used as a stationary phase. The structure of RBSP was characterized by infrared spectroscopy, thermal analysis and elemental analysis. The effect of methanol content in the mobile phase on chromatographic performance of the bonded stationary phase was investigated. The chromatographic performance of RBSP was also evaluated using the mixture of acidic, neutral and basic compounds as solute. The separating property was carried out using the bonded silica gel as a stationary phase of HPLC and methanol-water as the mobile phase by separating two kinds of soy isoflavones and several biological bases compared to C18. The chromatographic separation mechanism was also initially discussed. The results demonstrated that RBSP possessed good reversed-phase chromatographic behavior. At the same time, because the bonded stationary phase containing phenolic hydroxyl and amide groups can provide action sites for multiple compounds, it has the obvious advantage in separating polar compounds especially its fast separating rate. So the RBSP could be efficiently used for the separation of polar compounds.

Key words: high performance liquid chromatography, rhein bonded silica gel, soy isoflavone, chromatographic stationary phase