October 2020 Virtual Meeting

Speaker: Carlos Larriba-Andaluz, Indiana University–Purdue University Indianapolis

Topic: Understanding Ion Mobility Separation in High-Resolution Instruments. Caveats of and deviations from the Mason-Schamp Equation for small molecules

Date: Monday, October 19th, 2020

Time: 1:00 pm Presentation

Location: Webinar – see emails on Oct. 8 and 15 for invite link. Join the mailing list

Abstract: Ion mobility Spectrometry (IMS) is an analytical tool that has recently carried a great deal of interest in the field of Analytical Chemistry. As such, IMS is now ubiquitously present as an integrated part of many MS systems. This has resulted in major improvements in experimental setups, with very recent impressive achievements in terms of separation and peak capacity, alongside instruments like the Structure for Lossless Ion Manipulation (SLIM) or Field Asymmetric Waveform IMS (FAIMS) that have shown the capability of separating even isotopomers. Its progress is so remarkable that the theoretical ground commonly used to describe IMS has become insufficient to explain some experimentally observed separations; with some interpretations of this high-resolution separations remaining merely speculative at this point. It is therefore necessary to carefully analyze our common theoretical tools and describe the simplifications employed to arrive at equations such as the Mason-Schamp approximation so that a clear picture is provided on when these estimations may be employed. An effort is made to provide a concise and simple explanation of the simplifications that result on the Mason-Schamp equation. This is done from a method of moments perspective (up to the two-temperature theory) with an estimate of the error for different types of approximations. Based on this knowledge, a numerical tool, IMoS 2, that models an ion in a physical gas with the ability to stochastically calculate the drift velocity for a rotating ion under an arbitrary field, is proposed that may explain some of these separations recently observed.
Three main issues have been addressed in this work: 1) how the Collision Cross Section (CCS) is calculated and when its validity may be compromised due to rotation, moment of inertia or dipole alignment and other influences, 2) the effect of the electric field; when is it safe to ignore and when it should be included, and 3) the influence of higher order corrections even for low fields and small masses. The main idea of these theoretical study and simulations is to ascertain the resolution required in an IMS instrument for any of these effects to be noticeable, which will establish whether or not an empirically observed separation is due to some of these influences, and if it is, to perhaps improve instrument separation by underlining the cause. Preliminary analysis of the equations show that the Mason-Schamp approximation can have up to 4-10% deviations from the exact mobility values at low fields of spherical ions with particular emphasis on very small ions. Part of the deviations may be halved by choosing suitable ion-potential parameters, but this solution is dubiously the most promising way, as the authentic influence of the potentials and higher order effects is obscured. When increasing the field, a shift in mobility starts to be visible even below 8-10 Townsends and can represent up to a deviation of 15-30% for small ions in systems with high field to density ratios. The effect becomes larger for ions with existing dipole moments. The isotopomer separation effect is shown to be tied to differences in the moment of inertia producing shifts in mobility through the speed of rotation of the ion in the gas field. This explanation is supported by experimental results.

September 2020 Virtual Meeting

Speaker: Joe Cannon, Merck

Topic: Simplifying Cyclic Peptide Hydrolysis Interpretation in Metabolite Identification

Date: Monday, September 21st, 2020

Time: 1:00 pm Presentation

Location: Webinar – see emails on Sept. 10 and 18 for invite link. Join the mailing list

Abstract: Peptides, as therapeutics, can be used to disrupt crucial protein-protein interactions in disease states. As a modality, they offer an exciting compromise between large molecule-like specificity and small molecule-like absorption and distribution, all without the need for orthosteric binding. Despite these favorable properties, peptides suffer from short in vivo half-life due to protease mediated hydrolysis. To combat this, peptides are often conjugated and internally crosslinked to enhance rigidity or cyclized to decrease susceptibility to amino and carboxypeptidases. For linear peptides, identifying the site of hydrolysis is simple and similar to peptide identification in proteomics experiments. For cyclized peptides, it is very challenging due to the fact that hydrolysis simply linearizes the molecule, and the mass of a peptide from hydrolysis at one position is isobaric with every other position. 2-pyridine carboxaldehyde (2PCA) is used here to selectively conjugate the N-terminal amino acid and provide an amino acid specific low mass reporter fragment ion doublet that points to the site of hydrolysis. The chemistry is demonstrated here on a HeLa tryptic digest and proof-of-concept studies are shown on cyclic peptides.

June 2020 Virtual Meeting

Topic: Post-ASMS Virtual Poster Night and ASMS Travel Award Presentations

Date: Monday, June 22nd, 2020

Time: Poster listing online; 1:00 pm Presentations (Zoom link in June 11, 19 email)

ASMS Travel Award Recipients:

    • Gessica Vasconcelos, George Washington University

: “Fiber-based laser ablation electrospray ionization mass spectrometry for molecular profiling and metabolite gradients in anatomical regions selected by fluorescence microscopy”

    • Kunyu Zheng, Georgetown University

: “Non-targeted detection of fluorinated compounds using dielectric barrier discharge nano-electrospray ionization”

    • Yulemni Morel, Univ. of Maryland School of Pharmacy

: “Integrating Qual/Quan Workflows for Combined Structure Characterization and Quantitation of Vinyl Ether Phosphatidylethanolamine”

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WBMSDG attendees are invited to submit their posters for an online listing in lieu of an in-person poster night. Submit yours via the form below!

MP 031 Non-proximate Ambient Sampling for Solvent-free Analysis of Intact Objects; G. Asher Newsome1; Kathleen Martin2; Julia Campbell-Such3; 1Smithsonian Museum Conservation Institute, Suitland, MD; 2Smithsonian National Museum of the American Indian, Hillcrest Heights, MD; 3Smithsonian National Museum of African Art, Washington, DC

MP 206 Optimization of a targeted, multi-allergen LC-MS/MS method for the quantification of egg, milk, and peanut in food; Weili Xiong1; Christine H. Parker1; Katherine L. Fiedler1; 1U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, MD

MP 296 The Inelasticity of Ion-Molecule Collisions in Ion Mobility Spectrometry, Glenn Spangler, Technispan LLC

MP 355 Hepatic dyslipidemia in little brown bats (Myotis lucifugus) and big brown bats (Eptesicus fuscus) with white nose syndrome; Evan L. Pannkuk1; Nicole A. S.-Y. Dorville2; Yvoone A. Dzal2; Quinn E. Fletcher2; Kaleigh J. O. Norquay2; Craig K. R. Willis2; Albert J. Fornace Jr.1,3; Evagelia C. Laiakis1,3; 1Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC; 2Department of Biology, University of Winnipeg, Winnipeg, MB; 3Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC

TP 265 Enhanced Ionization and Facile Selection of Ions at Atmospheric-pressure by Perturbation-induced Pulsing of nano-ESI Coupled to a Single Ion Gate; William McMahon and Kaveh Jorabchi; Department of Chemistry, Georgetown University, Washington, DC

TP 516 Measuring protein conformational change in living cells by quantitative, comprehensive, and ultra-sensitive protein footprinting. Jenna G. Caldwell1*, Bjorn-Erik Wulff1, Lichao Zhang2, Joshua E. Elias2, Pehr A.B. Harbury2. 1Department of Biochemistry, Stanford School of Medicine, Stanford, CA; 2Chan Zuckerberg Biohub, Stanford, CA

WP 020 Identification approaches of the efflorescence detected in Infinity of Nations at the Smithsonian National Museum of the American Indian; Alba Alvarez-Martin* [1]; John George [2]; Emily Kaplan [2]; Lauren Osmond [2]; Leah Bright [2]; G. Asher Newsome [1]; Gwénaëlle Kavich [1]; Rachel Kaczkowski [1]; Susan Heald [2]. [1] Museum Conservation Institute, Smithsonian Institution, Suitland, MD; [2] The National Museum of the American Indian, Smithsonian Institution, Washington, DC

WP 462 Mass Spectrometric Approaches for the Structural Characterization of Chemically Targeted PreQ1 Riboswitches; Christopher C. Lai1; Desta D. Bume1; John S. Schneekloth, Jr.1; James A. Kelley1. 1Chemical Biology Laboratory, Center for Cancer Research, NCI-Frederick, National Institutes of Health, Frederick, MD

ThP 279 Trypsin – a Tired Workhorse? The Selectivity of Atypical Cleavages by Trypsin; Meghan Burke1; Yuxue Liang1; Stephen E. Stein1; 1National Institute of Standards and Technology, Gaithersburg, Maryland

ASMS 2020 Reboot

We hope all the WBMSDG members are having virtual fun at the ASMS 2020 Reboot! Remember, all content will be viewable until August 31. Use the hashtags #ASMS2020 and #WBMSDG on social media to highlight research from our community!

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The organizers at ASMS are putting together a Zoom happy hour for the mass spec community and trainees are especially encouraged to participate and socialize! The happy hour caps at 100 participants.
Registration for US/night owls (Jun 8, 2020 05:30 PM to 09:30 PM EDT): (closed)

Waters IMS webinars

Join Waters for a FREE webinar on:

The Revolutionary Cyclic IMS and an Exploration of its Capabilities

Advances in mass spectrometry (MS) made during the past century have helped empower scientists to research applications in the life, chemical and material sciences. It is the challenging problems that researchers face that underpin innovation in high performance

Presentation I:
Introduction to Ion Mobility and the SELECT SERIES Cyclic IMS
Discover how revolutionary cyclic ion mobility separation is combined with modern, state‐of‐the‐art time‐of‐flight mass spectrometry to overcome traditional limitations and provide new approaches. The novel cyclic ion mobility device provides scalable, high‐resolution ion mobility separations and provides the ability to perform ion mobility/ion mobility and IMSn experiments.
Kevin Giles
Scientific Fellow
Waters MS Research
Waters Corporation

Presentation II:
Cyclic IMS – Applications, Benefits and the Future…
Learn how the unique capabilities of Cyclic Ion Mobility Mass Spectrometry are enabling researchers to unlock new information in drug discovery, biomolecular characterization, biomarker research and many other application areas and how users are influencing further development of this system.
Emma Marsden-Edwards
Principal Product Manager
Waters Advanced MS Technologies
Waters Corporation

Each presentation is 30 minutes, and at the end of the second presentation there will be a 30 minute Q&A session. Learn more or register