Electron capture dissociation of polypeptides in a three-dimensional quadrupole ion trap: Implementation and first results.
The adverse influence of the radio frequency (RF) voltage on electrons has been the main obstacle for the implementation of electron capture dissociation (ECD) in three-dimensional quadrupole ion traps (3D QITs). Here we demonstrate that the use of axial magnetic field, together with the injection of low-energy (<5 eV) electrons, in the beginning of the positive RF semi-period achieves trapping of electrons for a period of time comparable with the semi-period duration. Importantly, the energy of the electrons remains low during most of the trapping period. With this technique, which we call "magnetized electrons, in-phase injection" (MEPhI), ECD and other ion-electron reactions have become possible in a 3D QIT. Initial ECD results, including single-scan data, were obtained with dications of Substance P. The observed secondary fragmentation of ECD fragments indicates that the trapped electrons are still somewhat hotter than desired.
Silivra
Oleg A
OA
Laboratory for Biological and Medical Mass Spectrometry, Uppsala University, Uppsala, Sweden.
Kjeldsen
Frank
F
Ivonin
Igor A
IA
Zubarev
Roman A
RA
D004583:Electrons; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods*; D007477:Ions; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D010455:Peptides / Q000737:chemistry*; D013373:Substance P / Q000032:analysis
D007477:Ions; D010455:Peptides; D013373:Substance P