Simultaneous determination of phenols (bibenzyl, phenanthrene, and fluorenone) in Dendrobium species by high-performance liquid chromatography with diode array detection.

A new method of analysis of 11 phenols, including five bibenzyls, three phenanthrenes, and three fluorenones, using high-performance liquid chromatography (HPLC)-diode array detection (DAD) was described. The separation of 11 phenols was effected by RP-HPLC (Beckman Coulter ODS column, 5 microm, 250 mm x 4.6 mm) using linear gradient elution systems of acetonitrile-1/1000 trifluoroacetic acid (TFA). Satisfactory separation of these compounds was obtained in less than 45 min. The method was validated for linearity, repeatability, limits of detection (LOD) and limits of quantification (LOQ). Good results were obtained with respect to repeatability (relative standard deviation (RSD)<3.5%) and recovery (85.77-104.92%). The developed method was applied to the simultaneous determination of 11 phenols from totally 31 Dendrobium species (mainly of medicinal plants) as well as other four samples from the similar genera as Pholidota, Flickingeria and Bulbophyllum. The range of the total amounts of bibenzyl, phenanthrene and fluorenone were found to from trace: 4.00, not detected (nd): 0.42 and nd: 0.24 microg mg(-1), respectively.