H2 unimolecular elimination in electrospray ionization mass spectrometry from erythraline, a spirocyclic alkaloid.

Erythrina alkaloids, which contain a spirocyclic structure, are well known due to their important biological activity at the central nervous system. In this study, systematic electrospray ionization tandem mass spectrometry (ESI-MS/MS) and ESI-multistage mass spectrometry (MS(n)) analysis of erythraline have shown an unexpected H2 neutral elimination reaction. We have investigated the formation of these ions by accurate-mass ESI-MS/MS with different analyzers and the data suggest a possible unimolecular reaction of H2 loss.