Field desorption mass spectra of the peptides Pro-Leu-Gly-NH2, Cbz-Gly-Pro-Leu-Gly-Pro and bradykinin

Field desorption mass spectra of a tripeptide Pro-Leu-Gly-NH2, a pentapeptide Cbz-Gly-Pro-Leu-Gly-Pro and a nonapeptide Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg are presented. In each case, a [M]+· or [M + 1]+ peak of the peptide is obtained. Sufficient fragmentation of the peptide backbone occurred to allow sequence determination of all three peptides. The pentapeptide produced [M]+·, [M + 1]+ and [M + 2]+· ions which also included molecules of ethylacetate, ethanol and/or water bound to the ion.