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 - res olution 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 databas e/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 com - pound 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 botan ical and dietary supplement sample s. 6500 系列四極桿(Q-TOF) 液質聯(lián)用系統(tǒng)