Capillary electrophoretic determination of the constituents of Artemisiae Capillaris Herba

Two capillary electrophoretic methods, a micellar electrokinetic electrophoretic (MEKC) one and a capillary zone electrophoretic (CZE) one, were developed for the separation of 12 constituents in Artemisiae Capillaris Herba. Detection at 254 nm with 20 mM sodium dodecyl sulfate and 20 mM sodium borate buffer (pH 9.82) in MEKC or with 25 mM sodium borate and 6.75 mg/ml 2,3,6-tri-O-methyl-β-cyclodextrin buffer in CZE was found to be the most suitable approach for this analysis. Within 42 min, the MEKC method could successfully separate 12 authentic constituents, whereof chlorogenic acid, however, appeared as a broad and split peak, and capillarisin and chlorogenic acid overlapped partially with other coexisting substances in crude extract of the herb. The CZE method could completely overcome these problems and was used to determine the amounts of capillarisin, chlorogenic acid, scopoletin and caffeic acid in the extract. The effect of buffers on the constituent separation and the validation of the two methods were discussed.