Separation of Isotopologues in Ultra-High-Resolution Ion Mobility Spectrometry

Kirk, Ansgar T.; Raddatz, Christian-Robert; Zimmermann, Stefan

doi:10.1021/acs.analchem.6b03300

Cited by 57 publications

(75 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…0.5% in CCS (e.g., 1 Å 2 at 200 Å 2 ). 54,55 In the ap-DTIMS examples chosen for this work, high resolution is achieved by operating the instrument at greater than atmospheric pressures (ca. 1050 Torr) and utilizing Hadamard transform multiplexing.…”

Section: Resultsmentioning

confidence: 99%

Correlating Resolving Power, Resolution, and Collision Cross Section: Unifying Cross-Platform Assessment of Separation Efficiency in Ion Mobility Spectrometry

2017

View full text Add to dashboard Cite

Here we examine the relationship between resolving power (Rp), resolution (Rpp), and collision cross section (CCS) for compounds analyzed in previous ion mobility (IM) experiments representing a wide variety of instrument platforms and IM techniques. Our previous work indicated these three variables effectively describe and predict separation efficiency for drift tube ion mobility spectrometry (DTIMS) experiments. In this work we seek to determine if our previous findings are a general reflection of IM behavior applicable to various instrument platforms and mobility techniques. Results suggest IM distributions are well characterized by a Gaussian model and separation efficiency can be predicted based on empirical difference in the gas-phase CCS and a CCS-based resolving power definition (CCS/ΔCCS). Notably traveling wave (TWIMS) was found to operate at substantially higher resolutions than a single-peak resolving power suggested. When a CCS-based Rp definition was utilized, TWIMS was found to operate at a resolving power of between 40 and 50, confirming the previous observations by Giles and coworkers. After converting the separation axis (and corresponding resolving power) to cross section space it is possible to effectively predict separation behavior for all mobility techniques evaluated (i.e. uniform field, trapped ion mobility, traveling wave, cyclic and overtone instruments) using the equations described in this work. Finally, we are able to establish for the first time that the current state-of-the-art ion mobility separations benchmark at a CCS-based resolving powers above 300 which is sufficient to differentiate analyte ions with CCS differences as small as 0.5%.

show abstract

Section: Resultsmentioning

confidence: 99%

Correlating Resolving Power, Resolution, and Collision Cross Section: Unifying Cross-Platform Assessment of Separation Efficiency in Ion Mobility Spectrometry

2017

View full text Add to dashboard Cite

show abstract

“…The specification of isotopic envelopes was not considered in IMS until very recently (Valentine & Clemmer, ), as all isotopologues were previously indistinguishable because of limited resolution. With the improvements in resolving power of both linear IMS and FAIMS, separation of isotopologues is now possible (Shvartsburg, Clemmer, & Smith, ; Kaszycki, Bowman, & Shvartsburg, ; Kirk, Raddatz, & Zimmermann, ) and necessitates defining the isotopic composition of species in question. By analogy to MS, we propose in linear IMS the monoisotopic ion mobility (raw or reduced) for the monoisotopic species, average mobility for the integral over full mobility distribution for all natural isotopologues, and most probable mobility for the most abundant isotopologue.…”

Section: Reporting Ion Mobility Measurementsmentioning

confidence: 99%

Recommendations for reporting ion mobility Mass Spectrometry measurements

Gabelica

Shvartsburg

Afonso

et al. 2019

Mass Spectrometry Reviews

370

477

View full text Add to dashboard Cite

Here we present a guide to ion mobility mass spectrometry experiments, which covers both linear and nonlinear methods: what is measured, how the measurements are done, and how to report the results, including the uncertainties of mobility and collision cross section values. The guide aims to clarify some possibly confusing concepts, and the reporting recommendations should help researchers, authors and reviewers to contribute comprehensive reports, so that the ion mobility data can be reused more confidently. Starting from the concept of the definition of the measurand, we emphasize that (i) mobility values ( K 0 ) depend intrinsically on ion structure, the nature of the bath gas, temperature, and E / N ; (ii) ion mobility does not measure molecular surfaces directly, but collision cross section (CCS) values are derived from mobility values using a physical model; (iii) methods relying on calibration are empirical (and thus may provide method‐dependent results) only if the gas nature, temperature or E / N cannot match those of the primary method. Our analysis highlights the urgency of a community effort toward establishing primary standards and reference materials for ion mobility, and provides recommendations to do so. © 2019 The Authors. Mass Spectrometry Reviews Published by Wiley Periodicals, Inc.

show abstract

“…32 This phenomenon fundamentally differs from the isotopic effect in linear IMS, where K depends primarily on the ion mass (via the reduced mass in Mason− Schamp equation). 33,34 The structural specificity of isotopic envelopes is another manifestation of the orthogonality of FAIMS to MS.…”

Section: ■ Introductionmentioning

confidence: 99%

Structurally Informative Isotopic Shifts in Ion Mobility Spectra for Heavier Species

Pathak

Baird

Shvartsburg

2019

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

The isotopic molecular envelopes due to stable isotopes for most elements were a staple of mass spectrometry since its origins, often leveraged to identify and quantify compounds. However, all isomers share one MS envelope. As the molecular motion in media also depends on the isotopic composition, separations such as liquid chromatography (LC) and ion mobility spectrometry (IMS) must also feature isotopic envelopes. These were largely not observed because of limited resolution, except for the (structurally uninformative) shifts in LC upon H/D exchange. We recently found the isotopic shifts in FAIMS for small haloanilines (∼130−170 Da) to hinge on the halogen position, opening a novel route to isomer characterization. Here, we extend the capability to heavier species: dibromoanilines (DBAs, ∼250 Da) and tribromoanilines (TBAs, ∼330 Da). The 13 C shifts for DBAs and TBAs vary across isomers, some changing sign. While 81 Br shifts are less specific, the 2-D 13 C/ 81 Br shifts unequivocally differentiate all isomers. The trends for DBAs track those for dichloroanilines, with the 13 C shift order preserved for most isomers. The peak broadening due to merged isotopomers is also isomer-specific. The absolute shifts for TBAs are smaller than those for lighter haloanilines, but differentiate isomers as well because of compressed uncertainties. These results showcase the feasibility of broadly distinguishing isomers in the more topical ∼200−300 Da range using the isotopic shifts in IMS spectra.

show abstract

Separation of Isotopologues in Ultra-High-Resolution Ion Mobility Spectrometry

Cited by 57 publications

References 31 publications

Correlating Resolving Power, Resolution, and Collision Cross Section: Unifying Cross-Platform Assessment of Separation Efficiency in Ion Mobility Spectrometry

Correlating Resolving Power, Resolution, and Collision Cross Section: Unifying Cross-Platform Assessment of Separation Efficiency in Ion Mobility Spectrometry

Recommendations for reporting ion mobility Mass Spectrometry measurements

Structurally Informative Isotopic Shifts in Ion Mobility Spectra for Heavier Species

Contact Info

Product

Resources

About