Roadmap for fragmentation of protonated methylarginines in the gas phase

- High resolution FT-ICR MS study of protonated methylarginines generated by AP-MALDI up to MS4 is performed.
- High resolution MS/MS enables us to unequivocally trace multiple dissociation pathways, some are previously unknown, leading to a given fragment ion.
- Several hitherto unreported isobaric fragments from the methylated arginines are observed for the first time.