Evaluation of Ionic Mobilities by Coupling the Scattering on Atoms and on Electron Density

Shvartsburg, Alexandre A.; Liu, Bei; Siu, Kin Wai Michael; Ho, Kai‐Ming

doi:10.1021/jp0004765

Cited by 49 publications

(73 citation statements)

References 43 publications

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“…For the ?5 and ?6 charge state ions, the CCSs of 4 are 1138.2 Å 2 and 1102.4 Å 2 , respectively; these values differ only slightly, indicating that the nanobelt possesses a rigid and shape-persistent conformation. Moreover, the measured CCSs agree well with the theoretical CCS (1093.1 Å 2 ) obtained from the energy-minimized structure by the trajectory method [44][45][46].…”

Section: Resultssupporting

confidence: 75%

Coordination-Driven, Self-Assembly of a Polycyclic, Terpyridine-Based Nanobelt

Xie

Guo

et al. 2016

J Inorg Organomet Polym

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Section: Resultssupporting

confidence: 75%

Coordination-Driven, Self-Assembly of a Polycyclic, Terpyridine-Based Nanobelt

Xie

Guo

et al. 2016

J Inorg Organomet Polym

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“…Electronic mail: clarriba@umn.edu is the CCS which uniquely defines ion mobility for different ions in a given bath gas, and thus facilitates IMS separation. Previously developed methods [8][9][10][11][14][15][16][17] for CCS calculation differ from one another primarily on the presumed manner in which impinging gas molecules are reemitted upon collision with the ion, which, outside of the large ion limit (i.e., below ∼ 10 nm in ion size) lead to significantly different CCSs. Seminal IMS studies using helium as a drift gas considered specular-elastic hard sphere scattering (EHSS) for gas molecule reemission, and show that in this gas such a reemission law can lead to good agreement between measured and calculated CCSs for ions with reasonably unambiguous structures.…”

Section: Introductionmentioning

confidence: 99%

Collision cross section calculations for polyatomic ions considering rotating diatomic/linear gas molecules

Larriba-Andaluz

Hogan

2014

The Journal of Chemical Physics

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Structural characterization of ions in the gas phase is facilitated by measurement of ion collision cross sections (CCS) using techniques such as ion mobility spectrometry. Further information is gained from CCS measurement when comparison is made between measurements and accurately predicted CCSs for model ion structures and the gas in which measurements are made. While diatomic gases, namely molecular nitrogen and air, are being used in CCS measurement with increasingly prevalency, the majority of studies in which measurements are compared to predictions use models in which gas molecules are spherical or non-rotating, which is not necessarily appropriate for diatomic gases. Here, we adapt a momentum transfer based CCS calculation approach to consider rotating, diatomic gas molecule collisions with polyatomic ions, and compare CCS predictions with a diatomic gas molecule to those made with a spherical gas molecular for model spherical ions, tetra-alkylammonium ions, and multiply charged polyethylene glycol ions. CCS calculations are performed using both specular-elastic and diffuse-inelastic collisions rules, which mimic negligible internal energy exchange and complete thermal accommodation, respectively, between gas molecule and ion. The influence of the long range ion-induced dipole potential on calculations is also examined with both gas molecule models. In large part we find that CCSs calculated with specular-elastic collision rules decrease, while they increase with diffuse-inelastic collision rules when using diatomic gas molecules. Results clearly show the structural model of both the ion and gas molecule, the potential energy field between ion and gas molecule, and finally the modeled degree of kinetic energy exchange between ion and gas molecule internal energy are coupled to one another in CCS calculations, and must be considered carefully to obtain results which agree with measurements.

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“…The quantity Ω avg (1,1) for any collider pair can be computed using various treatments. [41][42][43] This capability enables structural elucidation of ions by comparing mobilities calculated for candidate geometries with measurements. 24,25,27,28,[41][42][43][44] In FAIMS, ions are separated exploiting the dependence of ion mobility on the electric field.…”

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Two-Dimensional Gas-Phase Separations Coupled to Mass Spectrometry for Analysis of Complex Mixtures

et al. 2005

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Ion mobility spectrometry (IMS) has been explored for decades, and its versatility in separation and identification of gas-phase ions is well established. Recently, field asymmetric waveform IMS (FAIMS) has been gaining acceptance in similar applications. Coupled to mass spectrometry (MS), both IMS and FAIMS have shown the potential for broad utility in proteomics and other biological analyses. A major attraction of these separations is extremely high speed, exceeding that of condensed-phase alternatives by orders of magnitude. However, modest separation peak capacities have limited the utility of FAIMS and IMS for analyses of complex mixtures. We report 2-D gasphase separations that join FAIMS to IMS, in conjunction with high-resolution and accuracy timeof-flight MS. Implementation of FAIMS/IMS and IMS/MS interfaces using electrodynamic ion funnels greatly improves sensitivity. Evaluation of FAIMS/IMS/TOF performance for a protein mixture tryptic digest reveals high orthogonality between FAIMS and IMS dimensions, and hence the benefit of FAIMS filtering prior to IMS/MS. The effective peak capacities in analyses of tryptic peptides are ~500 for FAIMS/IMS separations and ~10 6 for 3-D FAIMS/IMS/MS, providing a potential platform for ultrahigh-throughput analyses of complex mixtures.Among the greatest challenges of analytical chemistry today is characterizing samples of enormous complexity associated with systems biology research. For example, mammalian proteomes can comprise >20,000 different proteins even before counting post-translational modifications, and sequence and splicing variants. 1 A proteolytic digestion of such a mixture following standard protocols of bottom-up proteomics 1 would yield >10 6 distinct peptides, and more if missed cleavage sites due to the inevitable imperfections in enzyme activity are considered. Individual peptides are commonly identified and quantified using massspectrometry (MS) that offers excellent sensitivity, specificity, and dynamic range. 1 However, no technique can presently characterize a significant percentage of the constituents in such a complex sample without extensive prior separations, and direct MS analyses generally identify with confidence only the most abundant proteins. "Top-down" analyses at the intact-protein level have similar limitations. Accordingly, combinations of various separation techniques with MS have become preeminent bioanalytical technologies. The separations have conventionally been performed in condensed phases (e.g., liquid chromatography, 2 LC, or capillary electrophoresis, 3 CE, and gel techniques 4 ). Single separation stages can provide peak capacities 2 of ~10 2 -10 3 . This level is insufficient for many challenging applications: in a mixture of ~10 6 components, a separated fraction would still comprise ~10 3 -10 4 co-eluting species on average, and substantially more in some cases. Hence large-scale proteomics often involves multidimensional separations using two or more different stages, followed by MS characterization. The be...

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Evaluation of Ionic Mobilities by Coupling the Scattering on Atoms and on Electron Density

Cited by 49 publications

References 43 publications

Coordination-Driven, Self-Assembly of a Polycyclic, Terpyridine-Based Nanobelt

Coordination-Driven, Self-Assembly of a Polycyclic, Terpyridine-Based Nanobelt

Collision cross section calculations for polyatomic ions considering rotating diatomic/linear gas molecules

Two-Dimensional Gas-Phase Separations Coupled to Mass Spectrometry for Analysis of Complex Mixtures

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