Collision‐activated decomposition of peptides by Fourier transform ion cyclotron resonance spectrometry

Abstract

AbstractThe dynamics of the collision‐activated decomposition (CAD) of large peptide ions by Fourier transform ion cyclotron resonance (FT‐ICR) spectrometry have been investigated in detail. The results presented concern [ M + H]+ ions of the cyclic depsipeptides beauvericin (M = 783.4 u) and valinomycin (M = 1110.6 u) and demonstrate that these peptide ions with less than 100 eV translational energy can undergo collisions with netrual gas atoms and decompose to yield abundant fragment ions. The effects of varying two parameters, the duration of the radiofrequency pulse used to accelerate the precursor ions and the time allowed for collisions, are illustrated. Increasing the former is shown to increase the extent and nature of CAD fragmentation; however, the same effect was not observed on increasing the collision time, and hence the number of collisions, at the pressures used in these experiments.