More Like this

1. Effective discrimination of gas-phase peptide conformers using TIMS-ECD-ToF MS/MS

   https://doi.org/10.1039/d1ay01461g  

   Jeanne Dit Fouque, K.; Wellmann, M.; Leyva Bombuse, D.; Santos-Fernandez, M.; Cintron-Diaz, Y. L.; Gomez-Hernandez, M. E.; Kaplan, D.; Voinov, V. G.; Fernandez-Lima, F. (November 2021, Analytical Methods)

   In the present work, four, well-studied, model peptides ( e.g. , substance P, bradykinin, angiotensin I and AT-Hook 3) were used to correlate structural information provided by ion mobility and ECD/CID fragmentation in a TIMS-q-EMS-ToF MS/MS platform, incorporporating an electromagnetostatic cell (EMS). The structural heterogeneity of the model peptides was observed by (i) multi-component ion mobility profiles (high ion mobility resolving power, R ∼115–145), and (ii) fast online characteristic ECD fragmentation patterns per ion mobility band (∼0.2 min). Particularly, it was demonstrated that all investigated species were probably conformers, involving cis / trans -isomerizations at X-Pro peptide bond, following the same protonation schemes, in good agreement with previous ion mobility and single point mutation experiments. The comparison between ion mobility selected ECD spectra and traditional FT-ICR ECD MS/MS spectra showed comparable ECD fragmentation efficiencies but differences in the ratio of radical (˙)/prime (′) fragment species (H˙ transfer), which were associated with the differences in detection time after the electron capture event. The analysis of model peptides using online TIMS-q-EMSToF MS/MS provided complementary structural information on the intramolecular interactions that stabilize the different gas-phase conformations to those obtained by ion mobility or ECD alone. 

   more » « less
2. High-throughput discovery of fluoride-ion conductors via a decoupled, dynamic, and iterative (DDI) framework

   https://doi.org/10.1038/s41524-022-00786-8  

   Sundberg, Jack D.; Druffel, Daniel L.; McRae, Lauren M.; Lanetti, Matthew G.; Pawlik, Jacob T.; Warren, Scott C. (May 2022, npj Computational Materials)

   Abstract Fluoride–ion batteries are a promising alternative to lithium–ion batteries with higher theoretical capacities and working voltages, but they have experienced limited success due to the poor ionic conductivities of known electrolytes and electrodes. Here, we report a high-throughput computational screening of 9747 fluoride-containing materials in search of fluoride-ion conductors. Via a combination of empirical, lightweight DFT, and nudged elastic band (NEB) calculations, we identified >10 crystal systems with high fluoride mobility. We applied a search strategy where calculations are performed in any order (decoupled), computational resources are reassigned based on need (dynamic), and predictive models are repeatedly updated (iterative). Unlike hierarchical searches, our decoupled, dynamic, and iterative framework (DDI) began by calculating high-quality barrier heights for fluoride-ion mobility in a large and diverse group of materials. This high-quality dataset provided a benchmark against which a rapid calculation method could be refined. This accurate method was then used to measure the barrier heights for 6797 fluoride–ion pathways. The final dataset has allowed us to discover many fascinating, high-performance conductors and to derive the design rules that govern their performance. These materials will accelerate experimental research into fluoride–ion batteries, while the design rules will provide an improved foundation for understanding ionic conduction. 

   more » « less
3. Perspective: The complex relationship between charge, mobility, and gas‐phase protein structure

   https://doi.org/10.1002/jms.5013  

   Webb, Ian_K (April 2024, Journal of Mass Spectrometry)

   Abstract Ion mobility spectrometry coupled to mass spectrometry (IMS/MS) is a widely used tool for biomolecular separations and structural elucidation. The application of IMS/MS has resulted in exciting developments in structural proteomics and genomics. This perspective gives a brief background of the field, addresses some of the important issues in making structural measurements, and introduces complementary techniques. 

   more » « less
4. An open source ion gate pulser for ion mobility spectrometry

   https://doi.org/10.1007/s12127-017-0223-x  

   Garcia, Luke; Saba, Carolyn; Manocchio, Gabriela; Anderson, Gordon A.; Davis, Eric; Clowers, Brian H. (October 2017, International Journal for Ion Mobility Spectrometry)

   Excluding the ion source, an ion mobility spectrometer is fundamentally comprised of drift chamber, ion gate, pulsing electronics, and a mechanism for amplifying and recording ion signals. Historically, the solutions to each of these challenges have been custom and rarely replicated exactly. For the IMS research community few detailed resources exist that explicitly detail the construction and operation of ion mobility systems. In an effort to address this knowledge gap we outline a solution to one of the key aspects of a drift tube ion mobility system, the ion gate pulser. Bradbury-Nielsen or Tyndall ion gates are found in nearly every research-grade and commercial IMS system. While conceptually simple, these gate structures often require custom, high-voltage, floating electronics. In this report we detail the operation and performance characteristics of a wifi-enabled, MOSFET-based pulser design that uses a lithium-polymer battery and does not require high voltage isolation transformers. Currently, each output of this circuit follows a TTL signal with ~20 ns rise and fall times, pulses up to +/− 200 V, and is entirely isolated using fiber optics. Detailed schematics and source code are provided to enable continued use of robust pulsing electronics that ease experimental efforts for future comparison. 

   more » « less
5. Integrating Ion Mobility and Imaging Mass Spectrometry for Comprehensive Analysis of Biological Tissues: A brief review and perspective

   https://doi.org/10.1002/jms.4614  

   Rivera, Emilio S.; Djambazova, Katerina V.; Neumann, Elizabeth K.; Caprioli, Richard M.; Spraggins, Jeffrey M. (July 2020, Journal of Mass Spectrometry)

   Imaging mass spectrometry (IMS) technologies are capable of mapping a wide array of biomolecules in diverse cellular and tissue environments. IMS has emerged as an essential tool for providing spatially targeted molecular information due to its high sensitivity, wide molecular coverage and chemical specificity. One of the major challenges for mapping the complex cellular milieu is the presence of many isomers and isobars present in these samples. This challenge is traditionally addressed using orthogonal LC-based analysis, though, common approaches such as chromatography and electrophoresis are not able to be performed at timescales that are compatible with most imaging applications. Ion mobility offers rapid, gas-phase separations that are readily integrated with IMS workflows in order to provide additional data dimensionality that can improve signal-to-noise, dynamic range, and specificity. Here, we highlight recent examples of ion mobility coupled to imaging mass spectrometry and highlight their importance to the field. 

   more » « less