Capillary electrophoretic determination of the constituents of Paeoniae radix

A method combining the techniques of capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) has been developed to separate a total of eight peony constituents. The CZE method was used to determine the content of paeonol, oxypaeoniflorin, benzoic acid, pentagalloylglucose and gallic acid, and MEKC technique based on sodium cholate was applied to analyze albiflorin, paeoniflorin, benzoylalbiflorin, paeonol and oxypaeoniflorin. Linearity around two orders of magnitude of concentration was generally obtained and limits of detection for these compounds were in the range of 2.6-23.7 μg/ml. The relative standard deviations of migration times were less than 1.43% (n = 6). Contents of peony constituents in an ethanol-water extract of Paeonia lactiflora Pall. sample could easily be determined by this method.