The Liquid Chromatographic Determination of Chlorogenic and Caffeic Acids in Xu Duan (Dipsacus asperoides) Raw Herb

A validated analytical method is reported for the analysis of chlorogenic and caffeic acids in Xu Duan (Dipsacus asperoides) in the dried raw herb. The ground samples were extracted by ultrasonication in water and the extract was analysed by LC-PDA with identity confirmation by (+)ESI-MS/MS. A C18 column was used with a 0.1% aqueous formic acid : methanol gradient mobile phase. The analytes were quantified 325 nm. With the MS detector, using the chlorogenic acid precursor ion with m/z 354, ions with m/z 191, and 85 were produced. For caffeic acid the precursor ion with m/z 181, ions with m/z 163, 135, and 89 were produced. The amount of chlorogenic and caffeic acids in the raw herb was found to be 4.46 and 0.63 mg/g, respectively, and the method LOD was 0.13 and 0.02 mg/g, respectively.