2P-27 PDF
Influence of Ion Residence Time on the Observation of Fragment Ions generated in In-Source Decay Experiments of β-Casein using MALDI-ISD MS
In-source decay (ISD) and collision-induced dissociation (CID) coupled with matrix-assisted laser desorption/ionization (MALDI) are powerful tools for the analysis of intact proteins. The resulting fragments in MALDI-ISD experiments are dependent on the ion optics such as quadruple ion trap and tandem time of flight. The peptide product ions, which are observed in CID, are influenced by several factors such as internal energy deposited in precursor ions and the ion residence timeframe in the reaction regions such as ion source and collision cell. In this study, we report the fragment ions generated with MALDI-ISD caused by radical-sites of the hydrogen-abundant radical species of a phosphorylated protein β-casein and its model peptide.