Numerical investigation of interface region flows in mass spectrometers: ion transport

Jugroot, Manish; Groth, C. P. T.; Thomson, Bruce A.; Baranov, Vladimir; Collings, B. A.

doi:10.1088/0022-3727/37/4/007

Cited by 17 publications

(18 citation statements)

References 40 publications

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“…The five-moment model has been used successfully in previous studies of ion transport in MS systems by Jugroot et al [12,13]. It provides 'one-way' coupling between the ion and neutral flows by incorporating the effects of ion-neutral collision processes.…”

Section: Introductionmentioning

confidence: 99%

Coupled gas and ion transport in quadrupole interfaces

Jugroot¹,

Groth²,

Thomson³

et al. 2008

J. Phys. D: Appl. Phys.

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The transport of free ions through highly under-expanded jet flows of neutral gases and in the presence of applied electric fields is investigated by continuum-based (fluid) numerical simulations. In particular, numerical results are described which are relevant to ion flows occurring in quadrupole interfaces of mass spectrometer systems. A five-moment mathematical model and parallel multi-block numerical solution procedure are developed for predicting the ion transport. The model incorporates the effects of ion-neutral collision processes and is used in conjunction with a Navier-Stokes model and flow solver for the neutral gas to examine the key influences controlling the ion motion. The effects of the neutral gas flow, electric fields (both dc and rf) and flow field geometry on ion mobility are carefully assessed. The capability of controlling the charged particle motions through a combination of directed neutral flow and applied electric field is demonstrated for these high-speed, hypersonic, jet flows. The neutral dynamics is shown to have a strong influence on the ion transport whereas the electric field imparts a more gradual effect. The combined effect of the applied (dc and rf) electric field and neutral collision processes with the dilute neutral gas results in a strong tendency for ion focusing towards the axis of symmetry, with the overall efficiency governed by the mass-to-charge ratio.

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Section: Introductionmentioning

confidence: 99%

Coupled gas and ion transport in quadrupole interfaces

Jugroot¹,

Groth²,

Thomson³

et al. 2008

J. Phys. D: Appl. Phys.

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“…If thermodynamic equilibrium is reached with the gas of Maxwellian particles, the frictional ion heating rate is equal to ion cooling rate [24]:…”

Section: Influence Of the Axial Drift Field On The Ion Energymentioning

confidence: 99%

The high-pressure segmented quadrupole collision cell (HP-SQCC) as an ion molecule reactor

Guo

Siu

Baranov³

2005

J. Am. Soc. Mass Spectrom.

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A high-pressure 20-segment quadrupole collision cell (HP-SQCC), which replaces a collision cell in a modified triple-quadrupole mass spectrometer is investigated in this work as an ion-molecule reactor with an inherent heat source. The highest working pressure achievable is 20 mTorr. The 20 quadrupole segments permit superimposition of linear axial electric field over the conventional quadrupole field in the radial direction. The axial and radial fields are employed to control ion temperature. Heat is transferred to the reactants through ion frictional heating. The HP-SQCC utilizes a combination of several physicochemical phenomena and an attempt is made to examine a range of ion-molecule reactions. Due to a sufficiently large number of reactive collisions, the reactor is used to promote sequential exothermic ion-molecule reactions. To characterize the performance of the HP-SQCC, the various ion-molecule reactions between the fragment ions of ferrocene ( on-molecule reactions have captured the fascination of mass spectrometrists for a number of decades and have been probed using a variety of instrumentation, including Fourier-transform ion cyclotron resonance spectrometry, ion-trap mass spectrometry, triplequadrupole mass spectrometry and the selected-ion flow tube technique [1]. The conventional triplequadrupole mass spectrometer is a less than perfect instrument for an examination of ion-molecule reactions due to the relatively low pressure achievable in its second quadrupole (Q 2 ), which restricts the number of ion-molecule collisions, and to the limited control of ion energy within Q 2 . Nevertheless, reactions that lead to novel products have been discovered; one such reaction is the ligand-exchange reaction between [Pb(CH 3 ; Pb 2ϩ had previously been described as to be among "a select group of doubly charged metal ions that will not form stable complexes in the gas phase with water" [3].Here we report the first ion-molecule reaction results obtained on a high-pressure 20-segment quadrupole collision cell (HP-SQCC) that functions as the Q 2 in a modified triple-quadrupole mass spectrometer. The highest working pressure achievable is 20 mTorr with neon, about 4 times higher than that achievable on a standard triple-quadrupole instrument. The 20 quadrupole segments permit superimposition of an axial electric field, typically linear, over the conventional quadrupole field in the radial direction [4][5][6]. The HP-SQCC was originally developed for ion-mobility measurements [5,7], where the goal is to maintain the drift field low enough that the ion temperature is not increased significantly. In this study, we are exploring the use of the HP-SQCC as an efficient apparatus for utilizing ion-molecule reactions as an analytical method. The axial and radial fields are employed to control the ion temperature.To characterize the performance of the HP-SQCC, we have elected to use as probes the various ionmolecule reactions between the fragment ions of ferrocene (Cp 2 Fe) as well as cobaltocene (Cp 2 Co) and neutra...

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“…For a two-dimensional axisymmetric coordinate frame, the potential equation has the form Figure 2. Schematic diagram of skimmer jet flow shock structure showing the the skimmer shock (S); the coalescing reflected compression waves from the jet boundary (J); the reflected shock (R); and the succession of expansion/recompression cells (from 9,16 ).…”

Section: Electric Potentialmentioning

confidence: 99%

“…The five-moment model has been used successfully in previous studies of ion transport in MS systems by Jugroot et al 8,9 It provides "one-way" coupling between the ion and neutral flows by incorporating the effects of ion-neutral collision processes. It also can account for effects of externally applied electric fields.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Coupled Neutral and Ion Transport in Quadrupole Interface Flows

Jugroot

Groth

Thomson³

et al. 2005

36th AIAA Plasmadynamics and Lasers Conference

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The transport of free ions through highly under-expanded jet flows of neutral gases and in the presence of applied electric fields is investigated by continuum-based numerical simulations. In particular, numerical results are described which are relevant to ion flows occurring in quadrupole interfaces of mass spectrometer systems. A five-moment mathematical model and parallel multi-block numerical solution procedure is developed for predicting the ion transport. The model incorporates the effects of ion-neutral collision processes and is used in conjunction with a Navier-Stokes model and flow solver for the neutral gas to examine the key influences controlling the ion motion. The effects of the neutral gas flow, electric fields (both dc and rf ), and flow field geometry on ion mobility are carefully assessed. The capability of controlling the charged particle motions through a combination of directed neutral flow and applied electric field is demonstrated for these high-speed, hypersonic, jet flows.

show abstract

Numerical investigation of interface region flows in mass spectrometers: ion transport

Cited by 17 publications

References 40 publications

Coupled gas and ion transport in quadrupole interfaces

Coupled gas and ion transport in quadrupole interfaces

The high-pressure segmented quadrupole collision cell (HP-SQCC) as an ion molecule reactor

Modeling of Coupled Neutral and Ion Transport in Quadrupole Interface Flows

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