Abstract
We investigated the fragmentation behavior of peptides and oligosaccharides using infrared multiple photodissociation (IRMPD) with a tunable IR free electron laser (FEL) in conjunction with Fourier-Transform Ion Cyclotron Resonance (FTICR) mass spectrometry (MS). The target ions of a protonated peptide (angiotensin II), protonated and sodiated saccharides (Lewis Y) were ionized by nano-electron spray ionization (ESI). The fragmentation behavior of these precursor ions was probed by monitoring the fragmentation of the ions induced by IRMPD in the IR wavelength range of 5.7-9.5μm. The results show that an abundance of the product ions from the peptide was mainly observed at 6.1μm, corresponding to the amide I band; these predominated due to contributions from the C = O stretching vibration of the peptide backbone. In the protonated ion of Lewis Y, the intensity of the fragment ions gradually increased on increasing the wavelength from 8.5μm. The curves for intensity peaked at a wavelength of around 9.1μm.
