Letter: High-Energy Electron Transfer Dissociation Using a Tandem Time-of-Flight Mass Spectrometer with an Electrospray Ionization Ion Source

Abstract

A tandem time-of-flight (TOF) mass spectrometer with an electrospray ionization (ESI) ion source (ESI-TOF/quadTOF) was enhanced to perform high-energy electron transfer dissociation (ETD) experiments. Specifically, the collision cell for rare gas targets of ESI-TOF/quadTOF was replaced with one for alkali metal targets. High-energy ETD spectra were obtained of doubly protonated polypeptides and a phosphopeptide using a Cs target. Peaks due to several c- and z-type fragment ions formed by the high-energy ETD process were clearly observed in all cases. These results demonstrate that high-energy ETD can be performed using ESI-TOF/quadTOF.