Mass fragmentation pattern of pyrrolizidine alkaloids found in Crotalaria species and in adults of Utetheisa ornatrix fed on these host plants.

a. Retention index in GC-MS analyses.b. Retention time (min) in LC-MS analyses. Some compounds detected by GC-MS were not detected (nd) by LC-MS.c. in free base form.d. in N-oxide form.e. Characterization of PAs by mass spectra using: 1Mass spectra matching with literature, 2.Interpretation of the mass spectrum from literature, 3Erroneously described in 29 as unknown senecionine-type.The analyses were carried out by gas chromatography-mass spectrometry (GC-MS) in electron impact mode and liquid chromatography-mass spectrometry (LC-MS) in electrospray ionization mode.