| Abstract: | Open tubular supercritical fluid chromatography (SFC) with carben dioxide as the mobile phase has been investigated for the separation of four triterpene acids, two of which were structural isomers. These compounds, isolated from Dysoxylum pettigrewianum (Meliaceae), were chromatographed on three stationary phases with different selectivities. 30%-biphenylmethylpolysiloxane and polyethylene glycol (Carbowax 20M) phases exhibited poor chromatographic selectivity for the compounds. The separation was improved by employing the shape selectivity of a liquid crystalline biphenylcarboxylate ester polysiloxane and utilizing simultaneous temperature and pressure programming. The elution order was explained on the basis of the molecular structures of the triterpene acids, and their interaction with the liquid crystal phase. |
