Field desorption collision activation linked scanning mass spectrometry of underivatized oligopeptides

Abstract

Field desorption production of protonated molecular ions from nanomole amounts of chemically underivatized penta-, tetra-and dipeptides, coupled with collision induced decomposition of [M + HI' ions, yielded partial amino acid sequence information. Linked scanning of two of the three fields detected ions produced in the first field free region of a double focusing mass spectrometer.

Daughter ion mass spectra from cationized molecules of small oligopeptides in a reflecting time-of-flight mass spectrometer

“…Tables II and III summarize the daughter ions obtained from cationized molecules of Leu-enkephalin and Met-enkephalin (3), respectively, which differ only in the C-terminal amino 2 and 3: R1= CH2C6H4OH ; R2 = R3= H ; R4=CH2C6H5 2: R5=CH2CH(CH3)2 (Leu) •, 3: R5=CH2CH2SCH3 (Met) acid. Since methionine has a molecular mass 18 u greater than that of leucine, it is easily possible to identify those ions containing the C-terminal amino acid residue.…”

“…The advantages of daughter ion mass spectra for structural analysis of ions have been well documented. Of particular relevance to this paper are a number of studies of small oligopeptides (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16).…”

Fast atom bombardment and tandem mass spectrometry for sequencing peptides and polyamino alcohols

“…Twenty scans were averaged for each peptide dissolved in acidified glycerol. Only 15 scans were acquired for the 16 ng sample because the beam was essentially undetectable after 15 scans. Additional acquisitions only reduced the S/N ratio.…”

“…The choice of a desorption technique depends on the strengths of the individual method and the type of information needed. For example, field desorption mass spectrometry (FD-MS) yields primarily molecular ion information and has been shown to be a good technique for the quantification of peptides at the nonogram level ( 14), Fragmentation information has been obtained by using collision activated dissociation (CAD) (15,16) and by submitting the sample to a digestion process (17). A static SIMS method (18) makes use of the excellent sensitivity observed for quaternary ammonium salt derivatives of small peptides to obtain sequence information with improved S/N.…”

Fast atom bombardment mass spectrometry of triterpenic saponins

“…arabinose, and gives rise to formation of the m/z 471 ion corresponding to the terpenic aglycone moiety. Therefore the saccharide sequence could be elucidated step by step and the proposed hederacoside C (11) structure was confirmed.…”