A gated trapping strategy with a two-time constant and a delay for catching in-field generated ions that range over three decades in mass-to-charge and two decades in velocity in Fourier-transform mass spectrometry.
In-field, matrix-assisted laser desorption/ionization (MALDI) may provide a means to keep part of the original promise of Fourier-transform mass spectrometry (FTMS) to give high performance and versatile mass spectrometry from a mechanically simple instrument. Gated trapping has been employed as a means of catching MALDI-produced ions in the FTMS trap. This approach is important for both in-field and externally produced ions. Even with improvements, gated trapping has not yet been able to catch ions over wide ranges of mass-to-charge and velocity. A design of a "two-time constant with a delay" gated trapping strategy using "idealized" potentials in a normalized system is given as an example to establish that in principle gated trapping strategies can capture ions that range over three decades of m/z and two decades in velocity. A procedure for calculating a physical system from the normalized system is given. The design is tolerant of variations in the physical parameters used to define the physical system from the normalized system.
Department of Chemistry, Washington University, St Louis, Missouri 63130, USA. rempel@wuchem.wustl.edu
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D000465:Algorithms; D004574:Electromagnetic Fields; D005583:Fourier Analysis; D013058:Mass Spectrometry / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization