Infrared Multiphoton Dissociation Spectroscopic Analysis of Peptides and Oligosaccharides by Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry with a Midinfrared Free-Electron Laser

• Published in: The journal of physical chemistry. B Vol. 110; no. 32; pp. 16111 - 16116
• Main Authors: Fukui, Kazuhiko, Takada, Yasutoshi, Sumiyoshi, Tetsumi, Imai, Takayuki, Takahashi, Katsutoshi
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 17-08-2006
• Subjects: Electrons; Fourier Analysis; Lasers; Oligosaccharides - analysis; Peptides - analysis; Sensitivity and Specificity; Spectrometry, Mass, Electrospray Ionization - instrumentation; Spectrometry, Mass, Electrospray Ionization - methods; Spectrophotometry, Infrared - instrumentation; Spectrophotometry, Infrared - methods
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp0607824

The fragmentation of peptides and oligosaccharides in the gas phase was investigated by means of electrospray ionization Fourier transform ion cyclotron resonance (FTICR) mass spectrometry coupled with dissociation by a laser-cleavage infrared multiphoton dissociation (IRMPD) technique. In this technique, an IR free-electron laser is used as a tunable source of IR radiation to cause cleavage of the ionized samples introduced into the FTICR cell. The gas-phase IRMPD spectra of protonated peptides (substance P and angiotensin II) and two sodiated oligosaccharides (sialyl Lewis X and lacto-N-fucopentaose III) were obtained over the IR scan range of 5.7−9.5 μm. In the IRMPD spectra for the peptide, fragment ions are observed as y/b-type fragment ions in the range 5.7−7.5 μm, corresponding to cleavage of the backbone of the parent amino acid sequence, whereas the spectra of the oligosaccharides have major peaks in the range 8.4−9.5 μm, corresponding to photoproducts of the B/Y type.