Simultaneous determination of gallic acid, albiflorin, paeoniflorin, ferulic acid and benzoic acid in Si-Wu decoction by high-performance liquid chromatography DAD method.

A high-performance liquid chromatographic method was applied to the determination of gallic acid, albiflorin, paeoniflorin, ferulic acid and benzoic acid in Si-Wu decoction and other 13 combinations of the formula. These five compounds were analyzed simultaneously with a Zorbox SB C-18 column by gradient elution using 0.01% (v/v) phosphoric acid-acetonitrile as the mobile phase. The flow rate was 1 ml min(-1), and detection was set at 230 nm. The recovery of the method was in the range of 94.8-103.1%, and all the compounds showed good linearity (r>0.9995) in a relatively wide concentration range. The result indicated that the content of these five compounds changed after decocting process. The contents of paeoniflorin, albiflorin, ferulic acid and gallic acid increased and that of benzoic acid decreased significantly.