Analysis of taxol and related taxanes from taxus canadensis using liquid chromatography combined with mass spectrometry or tandem mass spectrometry

A liquid chromatography/mass spectrormetry (LC/MS) method using nebulizer-assisted electrospray (ionspray) is described for the analysis of taxol and related taxane analogs in plant extracts from Taxus canadensis. The method used a reverse-phase liquid chromatography gradient elution which was entirely compatible with the operation of ionspray ionization. Abundant protonated molecules with limited fragmentation were obtained using this ionization technique, and provided adequate sensitivity for monitoring taxol in crude resin extracts. The LC/MS method was evaluated for the analysis of taxol present at levels of 0.2% in resin extracts. Using selected-ion monitoring, the method provided detection limits of 50 ng/mL. In addition, other taxane analogs were identified in crude resin extracts using liquid chromatography combined with tandem mass spectrometry. Parent-ion scans for a fragment ion characteristic of the taxane nucleus provided the necessary selectivity and sensitivity for the identification of potentially active diterpenes in complex extracts.