Pyrrolizidine Alkaloids: Characterization in Botanical and Dietary Supplements using Accurate-Mass Q-TOF LC/MS and All Ions MS/MS

Pyrrolizidine alkaloids (PAs) and their N-oxides (PANOs) have serious hepatotoxic effects in both humans and animals, necessitating a method capable of detecting, characterizing, and quantifying them using a robust assay. While triple quadrupole LC/MS systems are ideal for targeted detection, targeted analysis requires standards that are not always easily obtained. Only a fraction of known naturally occurring PAs are available as standards. Triple quadrupole analyses are also not useful for screening unknowns. High-resolution mass spectrometers that provide accurate-mass data enable characterization of unknown PAs/PANOs without the need for specific standards. This application note presents a workflow that uses accurate-mass Q-TOF LC/MS, with All Ions MS/MS and database/mass spectral library searching, for the selective and sensitive characterization, screening, tentative identification, and quantification of PAs and PANOs in botanicals and dietary supplements. Twenty-five PA/PANO standards were characterized using their high-resolution accurate-mass MS/MS spectra. These data were used to create a personal compound database and library (PCDL) that was then used to screen for PAs/PANOs in 44 botanical and dietary supplement samples. Quantitation was performed using Q-TOF LC/MS response. PAs/PANOs not specifically targeted were tentatively identified using characteristic fragment ions and fragmentation patterns. The PAs/PANOs characterized could potentially lead to the discovery of more unique PAs in additional botanical and dietary supplement samples.