On Performing Simultaneous Electron Transfer Dissociation and Collision Induced Dissociation on Multiply Protonated Peptides in a Linear Ion Trap

摘要

ETD/CID appears to rely upon the fundamental reactivity of the analyte cations to provide the best fragmentation, with b, y, c, and z-type ions generated and detected in a single experiment and a single mass spectrum. ETD/CID alleviates the problem posed by smaller peptide ions by acting in one of three ways: (1) ETD fragment ions are enhanced by CID of charge-reduced precursor ions; (2) both ETD and CID-derived fragments are produced; (3) predominantly CID-derived fragments are produced with little or no ETD-derived fragment ions. Smaller peptides that show little response to ETD are fragmented preferentially by CID during the ETD/CID experiment. Conversely, larger peptides with higher charge states are fragmented primarily via ETD.