FAST SEPARATION OF POLYMETHOXYLATED FLAVONES BY CARBON-DIOXIDE SUPERCRITICAL FLUID CHROMATOGRAPHY

The application of supercritical fluid chromatography (SFC) with modified carbon dioxide for the separation of polymethoxylated flavones (PMFs) is reported. The chromatographic system consists of a bare silica column (250 x 4.6 mm I.D.) with a carbon dioxide-methanol mobile phase and UV detection (313 nm). Selectivities are found to be different with this SFS system than with high-performance liquid chromatography (HPLC). All these naturally occurring PMFs (sinensetin, nobiletin, tangeretin, heptamethoxyflavone, tetramethylscutellarein) could be satisfactorily determined using an internal standard. The method was applied to the determination of PMFs in several Citrus oils. The SFC procedure is considerably faster than HPLC with good resolution and an adequate accuracy for the quantitative identification of PMFs.