Insight into the resonance ejection process during mass analysis through simulations for improved linear quadrupole ion trap mass spectrometer performance

A methodology for the simulation of mass analysis of ions in RF ion traps is described and demonstrated. This methodology utilizes the very high computational throughput capabilities of a GPU to accelerate ion trajectory modeling by similar to 10,000 fold over simple CPU based systems. This capability enables modeling of ion trajectories for realistic numbers of ions in realistic ion trap devices (defined by electrode structures and applied electrode voltages) and provides simulated mass spectral peaks as an end product. Comprehensive characterization of the effects on peak shape and resolution of electrode features such as slots or particular profiles, as well as critical operating parameters such as the amplitude and phase of the auxiliary voltages, is demonstrated. The simulated dependence of observed m/z peak resolution on auxiliary voltage phase and amplitude corresponds well with the results from a real commercial linear ion trap instrument. It is further confirmed via simulation that the extent of radial electrode displacement (stretch) for our commercial device corresponds to the minimum electrode displacement necessary to optimize m/z resolution. The results of a simulation study involving a set of 15 different ion trap configurations incorporating various trapping field compositions, electrode geometries, and applied voltages are presented. Several of the modeled trap configurations indicate the promise for improved m/z resolution. (C) 2014 Elsevier B.V. All rights reserved.