OPEN-TUBULAR SUPERCRITICAL-FLUID CHROMATOGRAPHY OF TRITERPENE ACIDS FROM DYSOXYLUM-PETTIGREWIANUM (MELIACEAE)

Open tubular supercritical fluid chromatography (SFC) with carbon diox ide as the mobile phase has been investigated for the separation of fo ur triterpene acids, two of which were structural isomers, These compo unds, isolated from Dysoxylum pettigrewianum (Meliaceae), were chromat ographed on three stationary phases with different selectivities. 30%- biphenylmethylpolysiloxane and polyethylene glycol (Carbowax 20M) phas es exhibited poor chromatographic selectivity for the compounds, The s eparation was improved by employing the shape selectivity of a liquid crystalline biphenylcarboxylate ester polysiloxane and utilizing simul taneous temperature and pressure programming. The elution order was ex plained on the basis of the molecular structures of the triterpene aci ds, and their interaction with the liquid crystal phase.