1
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Kinlein Z, Clowers BH. Altering Conformational States of Dynamic Ion Populations using Traveling Wave Structures for Lossless Ion Manipulations. Anal Chem 2024; 96:6450-6458. [PMID: 38603648 DOI: 10.1021/acs.analchem.4c00692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
With its capacity to store and translate ions across considerable distances and times, traveling wave structures for lossless ion manipulations (TW-SLIM) provide the foundation to expand the scope of ion mobility spectrometry (IMS) experiments. While promising, the dynamic electric fields and consequential ion-neutral collisions used to realize extensive degrees of separation have a considerable impact on the empirical results and the fundamental interpretation of observed arrival time distributions. Using a custom-designed set of TW-SLIM boards (∼9 m) coupled with a time-of-flight mass spectrometer (SLIM-ToF), we detail the capacity to systematically alter the gas-phase distribution of select peptide conformers. In addition to discussing the role charge-transfer may play in TW-SLIM experiments that occur at extended time scales, the ability of the SLIM-ToF to perform tandem IMS was leveraged to confirm that both the compact and elongated conformers of bradykinin2+ undergo interconversion within the SLIM. Storage experiments in which ions are confined within SLIM using static potential wells suggest that factors aside from TW-induced ion motion contribute to interconversion. Further investigation into this matter suggests that the use of radio frequency (RF) fields to confine ions within SLIM may play a role in ion heating. Aside from interconversion, storage experiments also provide insight into charge transfer behavior over the course of extended periods. The results of the presented experiments suggest that considerations should be taken when analyzing labile species and inform strategies for the TW-SLIM design and method development.
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Affiliation(s)
- Zackary Kinlein
- Department of Chemistry, Washington State University, Pullman, Washington 99164, United States
| | - Brian H Clowers
- Department of Chemistry, Washington State University, Pullman, Washington 99164, United States
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2
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Duque HM, Dos Santos C, Brango-Vanegas J, Díaz-Martín RD, Dias SC, Franco OL. Unwrapping the structural and functional features of antimicrobial peptides from wasp venoms. Pharmacol Res 2024; 200:107069. [PMID: 38218356 DOI: 10.1016/j.phrs.2024.107069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/07/2024] [Accepted: 01/09/2024] [Indexed: 01/15/2024]
Abstract
The study of wasp venoms has captured attention due to the presence of a wide variety of active compounds, revealing a diverse array of biological effects. Among these compounds, certain antimicrobial peptides (AMPs) such as mastoparans and chemotactic peptides have emerged as significant players, characterized by their unique amphipathic short linear alpha-helical structure. These peptides exhibit not only antibiotic properties but also a range of other biological activities, which are related to their ability to interact with biological membranes to varying degrees. This review article aims to provide updated insights into the structure/function relationships of AMPs derived from wasp venoms, linking this knowledge to the potential development of innovative treatments against infections.
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Affiliation(s)
- Harry Morales Duque
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, PC: (CEP) 70.790-160 Brasília, DF, Brazil.
| | - Cristiane Dos Santos
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, PC: (CEP) 79117-010 Campo Grande, MS, Brazil
| | - José Brango-Vanegas
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, PC: (CEP) 70.790-160 Brasília, DF, Brazil; S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, PC: (CEP) 79117-010 Campo Grande, MS, Brazil
| | - Ruben Dario Díaz-Martín
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, PC: (CEP) 70.790-160 Brasília, DF, Brazil
| | - Simoni Campos Dias
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, PC: (CEP) 70.790-160 Brasília, DF, Brazil; Program in Animal Biology, Universidade de Brasília, Brasília, DF70910-900, Brazil
| | - Octávio Luiz Franco
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, PC: (CEP) 70.790-160 Brasília, DF, Brazil; S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, PC: (CEP) 79117-010 Campo Grande, MS, Brazil
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3
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Schramm HM, Tamadate T, Hogan CJ, Clowers BH. Evaluation of Hydrogen-Deuterium Exchange during Transient Vapor Binding of MeOD with Model Peptide Systems Angiotensin II and Bradykinin. J Phys Chem A 2023; 127:8849-8861. [PMID: 37827113 DOI: 10.1021/acs.jpca.3c04608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
The advancement of hybrid mass spectrometric tools as an indirect probe of molecular structure and dynamics relies heavily upon a clear understanding between gas-phase ion reactivity and ion structural characteristics. This work provides new insights into gas-phase ion-neutral reactions of the model peptides (i.e., angiotensin II and bradykinin) on a per-residue basis by integrating hydrogen/deuterium exchange, ion mobility, tandem mass spectrometry, selective vapor binding, and molecular dynamics simulations. By comparing fragmentation patterns with simulated probabilities of vapor uptake, a clear link between gas-phase hydrogen/deuterium exchange and the probabilities of localized vapor association is established. The observed molecular dynamics trends related to the sites and duration of vapor binding track closely with experimental observation. Additionally, the influence of additional charges and structural characteristics on exchange kinetics and ion-neutral cluster formation is examined. These data provide a foundation for the analysis of solvation dynamics of larger, native-like conformations of proteins in the gas phase.
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Affiliation(s)
- Haley M Schramm
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
| | - Tomoya Tamadate
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Christopher J Hogan
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Brian H Clowers
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
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4
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Nagy K, Gellén G, Papp D, Schlosser G, Révész Á. Optimum collision energies for proteomics: The impact of ion mobility separation. JOURNAL OF MASS SPECTROMETRY : JMS 2023; 58:e4957. [PMID: 37415399 DOI: 10.1002/jms.4957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 05/28/2023] [Accepted: 06/19/2023] [Indexed: 07/08/2023]
Abstract
Ion mobility spectrometry (IMS) is a widespread separation technique used in various research fields. It can be coupled to liquid chromatography-mass spectrometry (LC-MS/MS) methods providing an additional separation dimension. During IMS, ions are subjected to multiple collisions with buffer gas, which may cause significant ion heating. The present project addresses this phenomenon from the bottom-up proteomics point of view. We performed LC-MS/MS measurements on a cyclic ion mobility mass spectrometer with varied collision energy (CE) settings both with and without IMS. We investigated the CE dependence of identification score, using Byonic search engine, for more than 1000 tryptic peptides from HeLa digest standard. We determined the optimal CE values-giving the highest identification score-for both setups (i.e., with and without IMS). Results show that lower CE is advantageous when IMS separation is applied, by 6.3 V on average. This value belongs to the one-cycle separation configuration, and multiple cycles may supposedly have even larger impact. The effect of IMS is also reflected in the trends of optimal CE values versus m/z functions. The parameters suggested by the manufacturer were found to be almost optimal for the setup without IMS; on the other hand, they are obviously too high with IMS. Practical consideration on setting up a mass spectrometric platform hyphenated to IMS is also presented. Furthermore, the two CID (collision induced dissociation) fragmentation cells of the instrument-located before and after the IMS cell-were also compared, and we found that CE adjustment is needed when the trap cell is used for activation instead of the transfer cell. Data have been deposited in the MassIVE repository (MSV000090944).
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Affiliation(s)
- Kinga Nagy
- MS Proteomics Research Group, Research Centre for Natural Sciences, Budapest, H-1117, Hungary
- Hevesy György PhD School of Chemistry, Faculty of Science, Institute of Chemistry, Eötvös Loránd University, Budapest, H-1117, Hungary
| | - Gabriella Gellén
- MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group, Faculty of Science, Institute of Chemistry, Eötvös Loránd University, Budapest, H-1117, Hungary
| | - Dávid Papp
- Hevesy György PhD School of Chemistry, Faculty of Science, Institute of Chemistry, Eötvös Loránd University, Budapest, H-1117, Hungary
- MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group, Faculty of Science, Institute of Chemistry, Eötvös Loránd University, Budapest, H-1117, Hungary
| | - Gitta Schlosser
- MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group, Faculty of Science, Institute of Chemistry, Eötvös Loránd University, Budapest, H-1117, Hungary
| | - Ágnes Révész
- MS Proteomics Research Group, Research Centre for Natural Sciences, Budapest, H-1117, Hungary
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5
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Ashworth EK, Dezalay J, Ryan CRM, Ieritano C, Hopkins WS, Chambrier I, Cammidge AN, Stockett MH, Noble JA, Bull JN. Protomers of the green and cyan fluorescent protein chromophores investigated using action spectroscopy. Phys Chem Chem Phys 2023. [PMID: 37465988 DOI: 10.1039/d3cp02661b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
The photophysics of biochromophore ions often depends on the isomeric or protomeric distribution, yet this distribution, and the individual isomer contributions to an action spectrum, can be difficult to quantify. Here, we use two separate photodissociation action spectroscopy instruments to record electronic spectra for protonated forms of the green (pHBDI+) and cyan (Cyan+) fluorescent protein chromophores. One instrument allows for cryogenic (T = 40 ± 10 K) cooling of the ions, while the other offers the ability to perform protomer-selective photodissociation spectroscopy. We show that both chromophores are generated as two protomers when using electrospray ionisation, and that the protomers have partially overlapping absorption profiles associated with the S1 ← S0 transition. The action spectra for both species span the 340-460 nm range, although the spectral onset for the pHBDI+ protomer with the proton residing on the carbonyl oxygen is red-shifted by ≈40 nm relative to the lower-energy imine protomer. Similarly, the imine and carbonyl protomers are the lowest energy forms of Cyan+, with the main band for the carbonyl protomer red-shifted by ≈60 nm relative to the lower-energy imine protomer. The present strategy for investigating protomers can be applied to a wide range of other biochromophore ions.
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Affiliation(s)
- Eleanor K Ashworth
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Jordan Dezalay
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | | | - Christian Ieritano
- Department of Chemistry, University of Waterloo, Waterloo N2L 3G1, Canada
| | - W Scott Hopkins
- Department of Chemistry, University of Waterloo, Waterloo N2L 3G1, Canada
| | - Isabelle Chambrier
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Andrew N Cammidge
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Mark H Stockett
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | | | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
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6
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Ieritano C, Haack A, Hopkins WS. Chemical Transformations Can Occur during DMS Separations: Lessons Learned from Beer's Bittering Compounds. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023. [PMID: 37310853 DOI: 10.1021/jasms.3c00040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
While developing a DMS-based separation method for beer's bittering compounds, we observed that the argentinated forms of humulone tautomers (i.e., [Hum + Ag]+) were partially resolvable in a N2 environment seeded with 1.5 mol % of isopropyl alcohol (IPA). Attempting to improve the separation by introducing resolving gas unexpectedly caused the peaks for the cis-keto and trans-keto tautomers of [Hum + Ag]+ to coalesce. To understand why resolution loss occurred, we first confirmed that each of the tautomeric forms (i.e., dienol, cis-keto, and trans-keto) responsible for the three peaks in the [Hum + Ag]+ ionogram were assigned to the correct species by employing collision-induced dissociation, UV photodissociation spectroscopy, and hydrogen-deuterium exchange (HDX). The observation of HDX indicated that proton transfer was stimulated by dynamic clustering processes between IPA and [Hum + Ag]+ during DMS transit. Because IPA accretion preferentially occurs at Ag+, which can form pseudocovalent bonds with a suitable electron donor, solvent clustering also facilitated the formation of exceptionally stable microsolvated ions. The exceptional stability of these microsolvated configurations disproportionately impacted the compensation voltage (CV) required to elute each tautomer when the temperature within the DMS cell was varied. The disparity in CV response caused the peaks for the cis- and trans-keto species to merge when a temperature gradient was induced by the resolving gas. Moreover, simulations showed that microsolvation with IPA mediates dienol to trans-keto tautomerization during DMS transit, which, to the best of our knowledge, is the first observation of keto/enol tautomerization occurring within an ion-mobility device.
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Affiliation(s)
- Christian Ieritano
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
- Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
- Watermine Innovation, Waterloo, Ontario N0B 2T0, Canada
| | - Alexander Haack
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
- Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - W Scott Hopkins
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
- Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
- Watermine Innovation, Waterloo, Ontario N0B 2T0, Canada
- Centre for Eye and Vision Research, 17 W Hong Kong Science Park, Shatin, New Territories 999077, Hong Kong
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7
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Haack A, Schaefer C, Zimmermann S, Hopkins WS. Validation of Field-Dependent Ion-Solvent Cluster Modeling via Direct Measurement of Cluster Size Distributions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:1035-1046. [PMID: 37116175 DOI: 10.1021/jasms.3c00012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Ion mobility spectrometry is widely used in analytical chemistry, either as a stand-alone technique or coupled to mass spectrometry. Ions in the gas phase tend to form loosely bound clusters with surrounding solvent vapors, artificially increasing the collisional cross section and the mass of the ion. This, in turn, affects ion mobility and influences separation. Further, ion-solvent clusters play an important role in most ionization mechanisms occurring in the gas phase. Consequently, a deeper understanding of ion-solvent cluster association and dissociation processes is desirable to guide experimental design and interpretation. A few computational models exist, which aim to describe the amount of clustering as a function of the reduced electric field strength, bath gas pressure and temperature, and the chemical species probed. It is especially challenging to model ion mobility under high reduced electrical field strengths due to the nonthermal conditions created by the field. In this work, we aim to validate a recently proposed first-principles model by comparing its predictions with direct measurements of cluster size distributions over a range of 20-120 Td as observed using a High Kinetic Energy Ion Mobility Spectrometer coupled to a mass spectrometer (HiKE-IMS-MS). By studying H+(H2O)n, [MeOH + H + n(H2O)]+, [ACE + H + n(H2O)]+, and [PhNH2 + H + n(H2O)]+ as test systems, we find very good agreement between model and experiment, supporting the validity of the computational workflow. Further, the detailed information gained from the modeling yields important insights into the cluster dynamics within the HiKE-IMS, allowing for better interpretation of the measured ion mobility spectra.
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Affiliation(s)
- Alexander Haack
- Department of Chemistry, University of Waterloo, 200 University Avenue W, Waterloo, Ontario N2L 3G1, Canada
| | - Christoph Schaefer
- Department of Sensors and Measurement Technology, Institute of Electrical Engineering and Measurement Technology, Leibniz University Hannover, 30167 Hannover, Germany
| | - Stefan Zimmermann
- Department of Sensors and Measurement Technology, Institute of Electrical Engineering and Measurement Technology, Leibniz University Hannover, 30167 Hannover, Germany
| | - W Scott Hopkins
- Department of Chemistry, University of Waterloo, 200 University Avenue W, Waterloo, Ontario N2L 3G1, Canada
- Watermine Innovation, Waterloo, Ontario N0B 2T0, Canada
- Centre for Eye and Vision Research, Hong Kong Science Park, New Territories, 999077, Hong Kong
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8
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Wu R, Metternich JB, Kamenik AS, Tiwari P, Harrison JA, Kessen D, Akay H, Benzenberg LR, Chan TWD, Riniker S, Zenobi R. Determining the gas-phase structures of α-helical peptides from shape, microsolvation, and intramolecular distance data. Nat Commun 2023; 14:2913. [PMID: 37217470 PMCID: PMC10203302 DOI: 10.1038/s41467-023-38463-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 04/19/2023] [Indexed: 05/24/2023] Open
Abstract
Mass spectrometry is a powerful technique for the structural and functional characterization of biomolecules. However, it remains challenging to accurately gauge the gas-phase structure of biomolecular ions and assess to what extent native-like structures are maintained. Here we propose a synergistic approach which utilizes Förster resonance energy transfer and two types of ion mobility spectrometry (i.e., traveling wave and differential) to provide multiple constraints (i.e., shape and intramolecular distance) for structure-refinement of gas-phase ions. We add microsolvation calculations to assess the interaction sites and energies between the biomolecular ions and gaseous additives. This combined strategy is employed to distinguish conformers and understand the gas-phase structures of two isomeric α-helical peptides that might differ in helicity. Our work allows more stringent structural characterization of biologically relevant molecules (e.g., peptide drugs) and large biomolecular ions than using only a single structural methodology in the gas phase.
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Affiliation(s)
- Ri Wu
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
| | - Jonas B Metternich
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
| | - Anna S Kamenik
- Laboratorium für Physikalische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
| | - Prince Tiwari
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Forschungsstrasse 111, 5232, Villigen PSI, Switzerland
| | - Julian A Harrison
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
| | - Dennis Kessen
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
- University of Münster, MEET Battery Research Center, Corrensstrasse 46, 48149, Münster, Germany
| | - Hasan Akay
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
| | - Lukas R Benzenberg
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
| | - T-W Dominic Chan
- Department of Chemistry, The Chinese University of Hong Kong, Hong Kong SAR, People's Republic of China
| | - Sereina Riniker
- Laboratorium für Physikalische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland.
| | - Renato Zenobi
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland.
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9
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Haack A, Hopkins WS. Kinetics in DMS: Modeling Clustering and Declustering Reactions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:2250-2262. [PMID: 36331115 DOI: 10.1021/jasms.2c00224] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Differential mobility spectrometry (DMS) uses high-frequency oscillating electrical fields to harness the differential mobility of ions for separating complex sample mixtures prior to detection. To increase the resolving power, a dynamic microsolvation environment is often created by introducing solvent vapors. Here, relatively large clusters are formed at low-field conditions which then evaporate to form smaller clusters at high-field conditions. The kinetics of these processes as the electrical field strength oscillates are not well studied. Here, we develop a computational framework to investigate how the different reactions (cluster association, cluster dissociation, and fast conformational changes) behave at different field strengths. We aim to better understand these processes, their effect on experimental outcomes, and whether DMS model accuracy is improved via incorporating their description. We find that cluster association and dissociation reactions for typical ion-solvent pairs are fast compared to the time scale of the varying separation fields usually used. However, low solvent concentration, small dipole moments, and strong ion-solvent binding can result in reaction rates small enough that a lag is observed in the ion's DMS response. This can yield differences of several volts in the compensation voltages required to correct ion trajectories for optimal transmission. We also find that the proposed kinetic approach yields generally better agreement with experiment than using a modified Boltzmann weighting scheme. Thus, this work provides insights into the chemical dynamics occurring within the DMS cell while also increasing the accuracy of dispersion plot predictions.
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Affiliation(s)
- Alexander Haack
- Department of Chemistry, University of Waterloo, 200 University Ave W, Waterloo, ONN2L 3G1, Canada
| | - W Scott Hopkins
- Department of Chemistry, University of Waterloo, 200 University Ave W, Waterloo, ONN2L 3G1, Canada
- Watermine Innovation, Waterloo, OntarioN0B 2T0, Canada
- Centre for Eye and Vision Research, Hong Kong Science Park, New Territories999077, Hong Kong
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10
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Ieritano C, Hopkins WS. The hitchhiker's guide to dynamic ion-solvent clustering: applications in differential ion mobility spectrometry. Phys Chem Chem Phys 2022; 24:20594-20615. [PMID: 36000315 DOI: 10.1039/d2cp02540j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This article highlights the fundamentals of ion-solvent clustering processes that are pertinent to understanding an ion's behaviour during differential mobility spectrometry (DMS) experiments. We contrast DMS with static-field ion mobility, where separation is affected by mobility differences under the high-field and low-field conditions of an asymmetric oscillating electric field. Although commonly used in mass spectrometric (MS) workflows to enhance signal-to-noise ratios and remove isobaric contaminants, the chemistry and physics that underpins the phenomenon of differential mobility has yet to be fully fleshed out. Moreover, we are just now making progress towards understanding how the DMS separation waveform creates a dynamic clustering environment when the carrier gas is seeded with the vapour of a volatile solvent molecule (e.g., methanol). Interestingly, one can correlate the dynamic clustering behaviour observed in DMS experiments with gas-phase and solution-phase molecular properties such as hydrophobicity, acidity, and solubility. However, to create a generalized, global model for property determination using DMS data one must employ machine learning. In this article, we provide a first-principles description of differential ion mobility in a dynamic clustering environment. We then discuss the correlation between dynamic clustering propensity and analyte physicochemical properties and demonstrate that analytes exhibiting similar ion-solvent interactions (e.g., charge-dipole) follow well-defined trends with respect to DMS clustering behaviour. Finally, we describe how supervised machine learning can be used to create predictive models of molecular properties using DMS data. We additionally highlight open questions in the field and provide our perspective on future directions that can be explored.
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Affiliation(s)
- Christian Ieritano
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada. .,Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.,Watermine Innovation, Waterloo, Ontario, N0B 2T0, Canada
| | - W Scott Hopkins
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada. .,Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.,Watermine Innovation, Waterloo, Ontario, N0B 2T0, Canada.,Centre for Eye and Vision Research, 17W Hong Kong Science Park, New Territories, 999077, Hong Kong
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11
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Haack A, Bissonnette JR, Ieritano C, Hopkins WS. Improved First-Principles Model of Differential Mobility Using Higher Order Two-Temperature Theory. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:535-547. [PMID: 35099948 DOI: 10.1021/jasms.1c00354] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Differential mobility spectrometry is a separation technique that may be applied to a variety of analytes ranging from small molecule drugs to peptides and proteins. Although rudimentary theoretical models of differential mobility exist, these models are often only applied to small molecules and atomic ions without considering the effects of dynamic microsolvation. Here, we advance our theoretical description of differential ion mobility in pure N2 and microsolvating environments by incorporating higher order corrections to two-temperature theory (2TT) and a pseudoequilibrium approach to describe ion-neutral interactions. When comparing theoretical predictions to experimentally measured dispersion plots of over 300 different compounds, we find that higher order corrections to 2TT reduce errors by roughly a factor of 2 when compared to first order. Model predictions are accurate especially for pure N2 environments (mean absolute error of 4 V at SV = 4000 V). For strongly clustering environments, accurate thermochemical corrections for ion-solvent clustering are likely required to reliably predict differential ion mobility behavior. Within our model, general trends associated with clustering strength, solvent vapor concentration, and background gas temperature are well reproduced, and fine structure visible in some dispersion plots is captured. These results provide insight into the dynamic ion-solvent clustering process that underpins the phenomenon of differential ion mobility.
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Affiliation(s)
- Alexander Haack
- Department of Chemistry, University of Waterloo, 200 University Avenue W, Waterloo, ON N2L 3G1, Canada
| | - Justine R Bissonnette
- Department of Chemistry, University of Waterloo, 200 University Avenue W, Waterloo, ON N2L 3G1, Canada
| | - Christian Ieritano
- Department of Chemistry, University of Waterloo, 200 University Avenue W, Waterloo, ON N2L 3G1, Canada
- Watermine Innovation, Waterloo, Ontario N0B 2T0, Canada
| | - W Scott Hopkins
- Department of Chemistry, University of Waterloo, 200 University Avenue W, Waterloo, ON N2L 3G1, Canada
- Watermine Innovation, Waterloo, Ontario N0B 2T0, Canada
- Centre for Eye and Vision Research, Hong Kong Science Park, New Territories 999077, Hong Kong
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