Simultaneous analysis of hepatotoxic pyrrolizidine alkaloids and N-oxides in comfrey root by LC-ion trap mass spectrometry.

The purpose of the current study was to develop a LC-MS(n) method for the analysis of pyrrolizidine alkaloids (PAs) in comfrey. Published data presents an extensive list of PAs and their N-oxides present in comfrey. However, standards are not commercially available for any of the PAs typically present in comfrey. Those PAs that are not stereoisomers were readily resolved on a C(18) column using a water-acetonitrile gradient as the mobile phase. The use of a selective technique, LC-MS/MS, allowed us to identify groups of PAs and their N-oxides, as well as identify the number of PAs present in each group, including those that were not completely resolved chromatographically.