Profiling of basic amino acids and polyamines in microbial culture supernatants by electrospray mass spectrometry


  • Part 9 in the series ‘Metabolites of Erwinia’; for Parts 7 and 8, see references 15 and 1, respectively. Presented, in part, at ALEX'93, San Francisco, California, October 5-7, 1993, and at the 42nd ASMS Conference, Chicago, Illinois, May 29-June 3, 1994.


As part of our efforts to investigate the biosynthesis of proferrioxamines in Erwinia amylovora, it was of interest to develop a methodology with which a large number of basic amino acids, di- and polyamines, and C- and N-hydroxy derivatives thereof could be monitored simultaneously. Towards this end, the on-line coupling of electrospray mass spectrometry with ion chromatography or reversed-phase chromatography was explored. Tandem mass spectrometry was found to be an excellent method for obtaining relevant structural information on underivatized polyamines and basic amino acid, including N-hydroxy derivatives. However, the coupling of ion chromatography with electrospray mass spectrometry for on-line extraction and separation of the underivatized compounds is hampered by compatibility problems. For most target compounds, on-line reversed-phase liquid chromatography/electrospray mass spectrometry was the method of choice but required derivatization and in this respect dansylation was preferred over benzoylation. Neither derivatization method is suitable for N-hydroxy compounds, which are basesensitive.