3P-29 PDF
Coulomb-Interaction-Induced Effects on FT-ICR Mass Spectra: A Many-Particle Simulation
In Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), ion motion trapped in the FT-ICR cell is essentially a superposition of three modes: cyclotron motion, magnetron motion and z motion. However, in practice, 103 to 106 different m/z ions are simultaneously trapped and excited in the cell and the ion cloud distribution consisting of each m/z ion ensemble and its temporal variation are quite complicated. Moreover at high ion density the Coulomb interactions between ions considerably influence the ion cloud distribution. In the early 1990s, simulation studies of 3D single ion trajectory were reported and those included no ion-ion Coulomb interactions. After large progress in computer performance a 3D many-particle model composed of 1,000 particles interacting with each other has been employed to simulate ion motion and mass spectra under realistic electric field conditions in a cubic FT-ICR cell. Further a special-purpose computer board (MD-One/E, Gazogiken and GRAPE-6 later) for many-body problems has been introduced and combined with a single processor PC. Thereby the computing configuration has been further accelerated. The simulation results reported thus far suggest that the relationship between the Coulomb-interaction-induced degradation and the FT-ICR mass spectral peak shape is quite complicated.