An innovative analytical method based on the off-line two-dimensional reversed-phase/reversed-phase liquid chromatography (2D-RPLC/RPLC) was established to separate the components of root of Rumex patientia L. The chromatograms of ethyl acetate extract of root of Rumex patientia L. on a phenyl/tetrazolium column (250 mm×4.6 mm, 7 μm) and a Unitary C18 column (250 mm×4.6 mm, 7 μm) were compared, and they showed different separation abilities. A phenyl/tetrazolium column was used for the first dimensional separation with 0.1% (v/v) formic acid aqueous solution and methanol as mobile phases, and 18 fractions was collected. The second dimensional liquid chromatography analysis was carried out on a Unitary C18 column with 0.1% (v/v) formic acid aqueous solution and methanol as mobile phases. Based on the experiment setup and results, it was concluded that off-line 2D-LC can be an effective method for the separation of the trace components and the screening of active compounds of root of Rumex patientia L.
Keywords: Rumex patientia L.; anthraquinone; phenyl/tetrazolium bonded stationary phase; two-dimensional liquid chromatography (2D-LC).