Laura Finazzi, Lara van Tetering, Jelle L. Schuurman, Jonathan Martens, Giel Berden and Jos Oomens*,
{"title":"芳香胺中质子化位点的捕获离子迁移率和红外离子光谱联合研究","authors":"Laura Finazzi, Lara van Tetering, Jelle L. Schuurman, Jonathan Martens, Giel Berden and Jos Oomens*, ","doi":"10.1021/jasms.5c00164","DOIUrl":null,"url":null,"abstract":"<p >The protonation site of aromatic amines in the gas phase has been under substantial debate, as it involves a subtle competition between the higher electronegativity of the amine nitrogen and the better charge delocalization ability of the fused aromatic rings. Previous studies have unambiguously shown, especially by ion mobility measurements, that higher-energy tautomers are easily observed depending on the experimental conditions in the ion source, including voltage settings and the type of solvent used in spray sources. Here, we use a combination of ion mobility and ion spectroscopy and focus on the tautomeric structure <i>after</i> ion mobility separation, in particular for protonated 1-aminonaphthalene and 1-aminoanthracene. We employ an atmospheric pressure chemical ionization (APCI) source, with a direct insertion probe to avoid any solvent influence, mounted on an FTICR mass spectrometer with a trapped ion mobility (TIMS) unit and optical access to the ions to perform infrared (IR) multiple-photon dissociation spectroscopy using the Free-Electron Laser for Infrared eXperiments (FELIX). TIMS analysis indeed reveals the presence of both N- and C-protonated species, but the IR spectra recorded in the ICR cell also suggest that mobilization and scrambling of the proton occur after TIMS separation. We computationally investigate the energetics of tautomerization and experimentally explore ion activation after TIMS separation.</p>","PeriodicalId":672,"journal":{"name":"Journal of the American Society for Mass Spectrometry","volume":"36 9","pages":"1940–1949"},"PeriodicalIF":2.7000,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/jasms.5c00164","citationCount":"0","resultStr":"{\"title\":\"Combined Trapped Ion Mobility and Infrared Ion Spectroscopy Study of Protonation Sites in Aromatic Amines\",\"authors\":\"Laura Finazzi, Lara van Tetering, Jelle L. Schuurman, Jonathan Martens, Giel Berden and Jos Oomens*, \",\"doi\":\"10.1021/jasms.5c00164\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p >The protonation site of aromatic amines in the gas phase has been under substantial debate, as it involves a subtle competition between the higher electronegativity of the amine nitrogen and the better charge delocalization ability of the fused aromatic rings. Previous studies have unambiguously shown, especially by ion mobility measurements, that higher-energy tautomers are easily observed depending on the experimental conditions in the ion source, including voltage settings and the type of solvent used in spray sources. Here, we use a combination of ion mobility and ion spectroscopy and focus on the tautomeric structure <i>after</i> ion mobility separation, in particular for protonated 1-aminonaphthalene and 1-aminoanthracene. We employ an atmospheric pressure chemical ionization (APCI) source, with a direct insertion probe to avoid any solvent influence, mounted on an FTICR mass spectrometer with a trapped ion mobility (TIMS) unit and optical access to the ions to perform infrared (IR) multiple-photon dissociation spectroscopy using the Free-Electron Laser for Infrared eXperiments (FELIX). TIMS analysis indeed reveals the presence of both N- and C-protonated species, but the IR spectra recorded in the ICR cell also suggest that mobilization and scrambling of the proton occur after TIMS separation. We computationally investigate the energetics of tautomerization and experimentally explore ion activation after TIMS separation.</p>\",\"PeriodicalId\":672,\"journal\":{\"name\":\"Journal of the American Society for Mass Spectrometry\",\"volume\":\"36 9\",\"pages\":\"1940–1949\"},\"PeriodicalIF\":2.7000,\"publicationDate\":\"2025-08-21\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://pubs.acs.org/doi/pdf/10.1021/jasms.5c00164\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of the American Society for Mass Spectrometry\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://pubs.acs.org/doi/10.1021/jasms.5c00164\",\"RegionNum\":2,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"BIOCHEMICAL RESEARCH METHODS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the American Society for Mass Spectrometry","FirstCategoryId":"92","ListUrlMain":"https://pubs.acs.org/doi/10.1021/jasms.5c00164","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"BIOCHEMICAL RESEARCH METHODS","Score":null,"Total":0}
Combined Trapped Ion Mobility and Infrared Ion Spectroscopy Study of Protonation Sites in Aromatic Amines
The protonation site of aromatic amines in the gas phase has been under substantial debate, as it involves a subtle competition between the higher electronegativity of the amine nitrogen and the better charge delocalization ability of the fused aromatic rings. Previous studies have unambiguously shown, especially by ion mobility measurements, that higher-energy tautomers are easily observed depending on the experimental conditions in the ion source, including voltage settings and the type of solvent used in spray sources. Here, we use a combination of ion mobility and ion spectroscopy and focus on the tautomeric structure after ion mobility separation, in particular for protonated 1-aminonaphthalene and 1-aminoanthracene. We employ an atmospheric pressure chemical ionization (APCI) source, with a direct insertion probe to avoid any solvent influence, mounted on an FTICR mass spectrometer with a trapped ion mobility (TIMS) unit and optical access to the ions to perform infrared (IR) multiple-photon dissociation spectroscopy using the Free-Electron Laser for Infrared eXperiments (FELIX). TIMS analysis indeed reveals the presence of both N- and C-protonated species, but the IR spectra recorded in the ICR cell also suggest that mobilization and scrambling of the proton occur after TIMS separation. We computationally investigate the energetics of tautomerization and experimentally explore ion activation after TIMS separation.
期刊介绍:
The Journal of the American Society for Mass Spectrometry presents research papers covering all aspects of mass spectrometry, incorporating coverage of fields of scientific inquiry in which mass spectrometry can play a role.
Comprehensive in scope, the journal publishes papers on both fundamentals and applications of mass spectrometry. Fundamental subjects include instrumentation principles, design, and demonstration, structures and chemical properties of gas-phase ions, studies of thermodynamic properties, ion spectroscopy, chemical kinetics, mechanisms of ionization, theories of ion fragmentation, cluster ions, and potential energy surfaces. In addition to full papers, the journal offers Communications, Application Notes, and Accounts and Perspectives