Ion Trajectory Simulations in a High-Pressure Cylindrical Ion Trap

Abstract

All rights reserved EuroPEAN JourNAL of MASS SPEctroMEtry there is a growing interest in the miniaturization of mass spectrometric devices for in situ analysis applications that include, in particular, environmental analysis. 1,2 conventional vacuum systems are often inappropriate because of size and mechanical considerations. thus, operation of mass analyzers at substantially higher pressure than customary pressures would be desirable. the ability to effectively focus and transmit ions at high pressure is a key factor that affects sensitivity and dynamic range in mass spectrometry. to improve the mass spectrometric sensitivity achievable for instance with electrospray ionization sources, ion funnel interfaces have been developed and successfully implemented in various mass spectrometric designs.3-10 An ion funnel is a stack of closely-spaced ring electrodes with decreasing internal diameters. A combination of rf and Dc potentials permits the focusing of ions at pressures that can reach ~10 torr. 6 However, the stacking of several tens of electrodes prevents easy miniaturization of such devices. the cylindrical geometry is physically simple to construct in a range of sizes, which render cylindrical ion traps attractive for miniaturization.11-13 the cylindrical ion trap can readily be fabricated in an appropriately small size; it provides tandem mass spectroscopy (MS/MS) capabilities and gives good sensitivity. the geometry of the cylindrical ion trap is amenable to multi-level microfabrication techniques 14-17 and the trap size and electrical requirements make it suitable for layout as a large array. 16 furthermore, rf ion trap mass analyzers can also be operated at relatively higher pressure than other mass analyzers, thus easing the requirements for the vacuum system. However, the trapping capablities of cylindrical ion traps are generally strongly altered at high-pressure regimes (greater than 2 torr) and stability diagrams at these regimes are still to be explored in detail. the operation of ion trap mass spectrometers in vacuum has been reviewed by March.18 the addition of a phenomenological term in the ion equation of motion has also allowed for a first exploration of the effects of a buffer gas pressure on ion trap stability. 19In the present work, we use an approach similar to the one proposed by Jarrold and co-workers for ion funnels.

Size Dependence of the Folding of Multiply Charged Sodium Cationized Polylactides Revealed by Ion Mobility Mass Spectrometry and Molecular Modelling

“…The cylindrical trap is an original feature that was designed to trap ions at intermediary pressures (ca. 10 Torr) 38. Ions are periodically ejected in the drift cell by applying a voltage of 10 V between the two cap electrodes.…”

“…10 Torr). [38] Ions are periodically ejected in the drift cell by applying a voltage of 10 V between the two cap electrodes. The drift cell is operated at a frequency of 3-6 Hz and the time width of the ion packet injected in the cell is 1 ms.…”

Statistical Analysis of Ion Mobility Spectrometry. I. Unbiased and Guided Replica-Exchange Molecular Dynamics

“…Briefly, the ions are formed in an electrospray ion source and transferred to a cylindrical ion trap [29] via an ion funnel. Ion bunches from the trap are periodically injected directly in a 1 m-long drift tube filled with 12 Torr of helium and maintained at 293 K. The duration of an ion pulse is 1 ms at the injection.…”

Alternative Representation for the Stability Diagram of Quadrupole Ion Traps upon Additional Quadrupolar Excitation

“…Moreover, the presence of a buffer-gas or the influence of the initial velocity distribution or divergence in the ion beam can be accounted for. 6,7 However, the numerical construction of the diagram requires the calculation of a high number of trajectories, which is highly time-consuming.…”