Publication
Routine Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with ion detection at the unreduced (true) cyclotron frequency, instead of the reduced cyclotron frequency, has recently been demonstrated experimentally and supported computationally. That initial computational work was performed with SIMION and particle-in-cell multiparticle simulations for narrow aperture detection electrode (NADEL) ICR cells with either dipolar or quadrupolar ion detection schemes, and led to the modeling of ion signal formation at the true cyclotron frequency. Here, we further develop the modeling to provide additional insights into operation of a NADEL ICR cell with quadrupolar ion detection (i.e., the 2xNADEL ICR cell), and study the cells' sensitivity for single and multiple ion detection over single and numerous cyclotron periods. Based on the ion simulations, compact ion bunching appears to provide a higher sensitivity at the reduced cyclotron frequency compared to spatially-distributed cyclotron oscillators that yield the true cyclotron frequency. The lower sensitivity for spatially-distributed cyclotron oscillators can be, potentially, compensated by adjusting the properties of the cell's electrodes (e.g., shape, overall dimensions, and number). In addition, the sensitivity performance may benefit from the exceptionally wide acceptance range for trapping potentials of the approach: simulations suggest that stable generation and detection of the true cyclotron frequency via spatially-distributed cyclotron oscillators are possible with up to 1000 V trapping potentials. (c) 2021 Elsevier B.V. All rights reserved.