1
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Carlo MJ, Nanney ALM, Patrick AL. Energy-Resolved In-Source Collison-Induced Dissociation for Isomer Discrimination. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024. [PMID: 39016059 DOI: 10.1021/jasms.4c00118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
While mass spectrometry remains a gold-standard tool for analyte detection, characterization, and quantitation, isomer differentiation is often a challenge. Tandem mass spectrometry is a common approach to increase the selectivity of mass spectrometry and energy-resolved measurements can provide further improvements. However, not all mass spectrometers, especially those that are very compact and affordable, are amenable to such experiments. For instance, single-stage mass spectrometers with soft ionization provide no dissociation information and quadrupole ion trap instruments with resonant excitation do not necessarily provide as informative of energy-resolved curves, for instance when extensive sequential dissociation is responsible for much of the "fingerprint". In-source collision-induced dissociation (IS-CID) is one approach to overcoming these barriers to exploit the analytical selectivity of energy-resolved CID without the need for additional instrumentation; this approach could broaden the reach of these selectivity gains to additional user bases (e.g., educational settings, field portable devices). Here, we specifically investigate energy-resolved IS-CID with the goal of (1) comparing between energy-resolved appearance curves measured with true tandem mass spectrometry on a quadrupole time-of-flight instrument and those obtained using IS-CID, (2) evaluating the approach as a means of differentiating isomers/isobar sets, especially those with similar dissociation patterns, and (3) exploring additional analytical considerations relevant to method development and implementation. This proof-of-concept work establishes the analytical potential of this approach, opening doors for future method development for specific applications.
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Affiliation(s)
- Matthew J Carlo
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Andie L M Nanney
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Amanda L Patrick
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
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2
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Habeck T, Maciel EVS, Kretschmer K, Lermyte F. Charge site manipulation to enhance top-down fragmentation efficiency. Proteomics 2024; 24:e2300082. [PMID: 37043727 DOI: 10.1002/pmic.202300082] [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: 02/10/2023] [Revised: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 04/14/2023]
Abstract
In recent years, top-down mass spectrometry has become a widely used approach to study proteoforms; however, improving sequence coverage remains an important goal. Here, two different proteins, α-synuclein and bovine carbonic anhydrase, were subjected to top-down collision-induced dissociation (CID) after electrospray ionisation. Two high-boiling solvents, DMSO and propylene carbonate, were added to the protein solution in low concentration (2%) and the effects on the top-down fragmentation patterns of the proteins were systematically investigated. Each sample was measured in triplicate, which revealed highly reproducible differences in the top-down CID fragmentation patterns in the presence of a solution additive, even if the same precursor charge state was isolated in the quadrupole of the instrument. Further investigation supports the solution condition-dependent selective formation of different protonation site isomers as the underlying cause of these differences. Higher sequence coverage was often observed in the presence of additives, and the benefits of this approach became even more evident when datasets from different solution conditions were combined, as increases up to 35% in cleavage coverage were obtained. Overall, this approach therefore represents a promising opportunity to increase top-down fragmentation efficiency.
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Affiliation(s)
- Tanja Habeck
- Department of Chemistry, Clemens-Schöpf-Institute of Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Hessen, Germany
| | - Edvaldo Vasconcelos Soares Maciel
- Department of Chemistry, Clemens-Schöpf-Institute of Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Hessen, Germany
| | - Kevin Kretschmer
- Department of Chemistry, Clemens-Schöpf-Institute of Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Hessen, Germany
| | - Frederik Lermyte
- Department of Chemistry, Clemens-Schöpf-Institute of Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Hessen, Germany
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3
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Ohshimo K, Sato R, Takasaki Y, Tsunoda K, Ito R, Kanno M, Misaizu F. Highly Efficient Intramolecular Proton Transfer in p-Aminobenzoic Acid by a Single Ammonia Molecule as a Vehicle. J Phys Chem Lett 2023; 14:8281-8288. [PMID: 37677142 DOI: 10.1021/acs.jpclett.3c01996] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Abstract
Proton transfer is classified into two mechanisms: the Grotthuss (proton-relay) and vehicle mechanisms. It has been well studied on gas-phase proton transfer by a proton relay involving multiple molecules. However, a vehicle mechanism in which a single molecule transports a proton has rarely been reported. Here, we have obtained clear evidence that the proton transfers efficiently between the two protonation sites in protonated p-aminobenzoic acid (PABA·H+) by a single ammonia molecule as a vehicle. The gaseous PABA·H+ ions were reacted with NH3 or ND3 under single-collision conditions in a cold ion trap, and the proton-transferred ions were identified by cryogenic ion mobility-mass spectrometry. A reaction intermediate PABA·H+·NH3 was also detected for the first time. The reaction pathway search calculations and ab initio molecular dynamics simulations supported the present experimental finding that intramolecular proton transfer occurs very efficiently by the vehicle mechanism.
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Affiliation(s)
- Keijiro Ohshimo
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Ryosuke Sato
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Yuya Takasaki
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Kengo Tsunoda
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Ryosuke Ito
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Manabu Kanno
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Fuminori Misaizu
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
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4
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Kumar M, Samarasinghe I, Attygalle AB. Dependence of Collision-Induced Mass Spectra of Protonated Michler's Ketone on the Nature of LC-MS Mobile Phase. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:1663-1674. [PMID: 37459424 DOI: 10.1021/jasms.3c00115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
Michler's ketone (MK) is a dimethylamino ketone that undergoes facile protonation under electrospray-ionization conditions to produce an ion of m/z 269. Initial LC-MS results showed that the collision-induced dissociation (CID) spectra of the m/z 269 ion depend heavily on the composition of the chromatographic mobile phase. Subsequent ion-mobility separation of the mass-selected m/z 269 ion revealed that protonated MK exists as two tautomeric forms. Moreover, the relative population of the two protomeric forms in the ion ensemble depends on the nature of the ambient molecules present in the atmospheric pressure ion source. For example, the ion-mobility arrival-time profile acquired from the mass-selected m/z 269 ion generated from an acetonitrile solution showed two peaks of near equal intensity. The peak with the shorter arrival time represented the O-protomer and that with the longer arrival time represented the N-protomer. However, when methanol or ammonia vapors were introduced to the ambient-pressure ion source, the intensity of the N-protomer peak decreased rapidly and that of the O-protomer signal soared until it became the dominant peak. When the introduction of methanol (or ammonia) vapors was stopped, the mobilogram signals gradually reverted back to their initial intensities. To rationalize this observation, we propose that the N-protomer of MK in the presence of methanol vapor undergoes transformation to the O-protomer by a Grotthuss-type mechanism via a methanol-based solvent bridge.
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Affiliation(s)
- Meenu Kumar
- Department of Chemistry, Chemical Biology and Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - Ishira Samarasinghe
- Department of Chemistry, Chemical Biology and Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - Athula B Attygalle
- Department of Chemistry, Chemical Biology and Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
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5
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Fernandes AS, Obeid G, Laureno TJN, Correra TC. Protonated and Sodiated Cyclophosphamide Fragmentation Pathways Evaluation by Infrared Multiple Photon Dissociation Spectroscopy. J Phys Chem A 2023. [PMID: 37285455 DOI: 10.1021/acs.jpca.3c01323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Cyclophosphamide (CP or CTX) is a widely used antineoplastic agent, and the evaluation of its efficacy and its impacts on the environment are dependent on tandem mass spectrometry (MSn) techniques. Because there is no dedicated experimental study to characterize the actual molecular nature of the CP fragments upon collision-induced dissociation, this work evaluated the chemical structure of the fragments of protonated and sodiated CP and CP protonation sites by infrared multiple photon dissociation spectroscopy supported by density functional theory calculations. This study allowed us to propose a new fragment structure and confirm the nature of multiple fragments, including those relevant for transitions used for CP quantitative and qualitative analyses. Our results also show that there is no spectroscopic evidence that can rule out the existence of aziridinium fragments, making it clear that further studies on the nature of iminium/aziridinium fragments in the gas phase are necessary.
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Affiliation(s)
- André S Fernandes
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo 05508-000, São Paulo, Brazil
| | - Guilherme Obeid
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo 05508-000, São Paulo, Brazil
| | - Tiago J N Laureno
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo 05508-000, São Paulo, Brazil
| | - Thiago C Correra
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo 05508-000, São Paulo, Brazil
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6
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Chakraborty P, Neumaier M, Weis P, Kappes MM. Exploring Isomerism in Isolated Cyclodextrin Oligomers through Trapped Ion Mobility Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:676-684. [PMID: 36952473 DOI: 10.1021/jasms.2c00351] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Cyclodextrin (CD) macrocycles are used to create a wide range of supramolecular architectures which are also of interest in applications such as selective gas adsorption, drug delivery, and catalysis. However, predicting their assemblies and identifying the possible isomers in CD oligomers have always remained challenging due to their dynamic nature. Herein, we interacted CDs (α, β, and γ) with a divalent metal ion, Cu2+, to create a series of Cu2+-linked CD oligomers, from dimers to pentamers. We characterized these oligomers using electrospray ionization mass spectrometry and probed isomerism in each of these isolated oligomers using high resolution trapped ion mobility spectrometry. Using this technique, we separated multiple isomers for each of the Cu2+-interlinked CD oligomers and estimated their relative population, which was not accessible previously using other characterization techniques. We further carried out structural analysis of the observed isomers by comparing the experimental collision cross sections (CCSs) to that of modeled structures. We infer that the isomeric heterogeneity reflects size-specific packing patterns of individual CDs (e.g., close-packed/linear). In some cases, we also reveal the existence of kinetically trapped structures in the gas phase and study their transformation to thermodynamically controlled forms by examining the influence of activation of the ions on isomer interconversion.
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Affiliation(s)
- Papri Chakraborty
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Marco Neumaier
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
| | - Patrick Weis
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Manfred M Kappes
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
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7
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Akasaka K, Hirata K, Haddad F, Dopfer O, Ishiuchi SI, Fujii M. Hydration-induced protomer switching in p-aminobenzoic acid studied by cold double ion trap infrared spectroscopy. Phys Chem Chem Phys 2023; 25:4481-4488. [PMID: 36514975 DOI: 10.1039/d2cp04497h] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Para-Aminobenzoic acid (PABA) is a benchmark molecule to study solvent-induced proton site switching. Protonation of the carboxy and amino groups of PABA generates O- and N-protomers of PABAH+, respectively. Ion mobility mass spectrometry (IMS) and infrared photodissociation (IRPD) studies have claimed that the O-protomer most stable in the gas phase is converted to the N-protomer most stable in solution upon hydration with six water molecules in the gas-phase cluster. However, the threshold size has remained ambiguous because the arrival time distributions in the IMS experiments exhibit multiple peaks. On the other hand, IRPD spectroscopy could not detect the N-protomer for smaller hydrated clusters because of broad background due to annealing required to reduce kinetic trapping. Herein, we report the threshold size for O → N protomer switching without ambiguity using IR spectroscopy in a double ion trap spectrometer from 1300 to 1800 cm-1. The pure O-protomer is prepared by electrospray, and size-specific hydrated clusters are formed in a reaction ion trap. The resulting clusters are transferred into a second cryogenic ion trap and the distribution of O- and N-protomers is determined by mid-IR spectroscopy without broadening. The threshold to promote O → N protomer switching is indeed five water molecules. It is smaller than the value reported previously, and as a result, its pentahydrated structure does not support the Grotthuss mechanism proposed previously. The extent of O → N proton transfer is evaluated by collision-assisted stripping IR spectroscopy, and the N-protomer population increases with the number of water molecules. This result is consistent with the dominant population of the N-protomer in aqueous solution.
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Affiliation(s)
- Kyota Akasaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan. .,School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8503, Japan
| | - Keisuke Hirata
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan. .,Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.,International Research Frontiers Initiative, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan.
| | - Fuad Haddad
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany
| | - Otto Dopfer
- International Research Frontiers Initiative, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan. .,Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany
| | - Shun-Ichi Ishiuchi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan. .,Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.,International Research Frontiers Initiative, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan.
| | - Masaaki Fujii
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan. .,School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8503, Japan.,International Research Frontiers Initiative, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan.
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8
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Sepman H, Tshepelevitsh S, Hupatz H, Kruve A. Protomer Formation Can Aid the Structural Identification of Caffeine Metabolites. Anal Chem 2022; 94:10601-10609. [PMID: 35861491 PMCID: PMC9352149 DOI: 10.1021/acs.analchem.2c00257] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
![]()
The structural annotation of isomeric metabolites remains
a key
challenge in untargeted electrospray ionization/high-resolution mass
spectrometry (ESI/HRMS) metabolomic analysis. Many metabolites are
polyfunctional compounds that may form protomers in electrospray ionization
sources and therefore yield multiple peaks in ion mobility spectra.
Protomer formation is strongly structure-specific. Here, we explore
the possibility of using protomer formation for structural elucidation
in metabolomics on the example of caffeine, its eight metabolites,
and structurally related compounds. It is observed that two-thirds
of the studied compounds formed high- and low-mobility species in
high-resolution ion mobility. Structures in which proton hopping was
hindered by a methyl group at the purine ring nitrogen (position 3)
yielded structure-indicative fragments with collision-induced dissociation
(CID) for high- and low-mobility ions. For compounds where such a
methyl group was not present, a gas-phase equilibrium could be observed
for tautomeric species with two-dimensional ion mobility. We show
that the protomer formation and the gas-phase properties of the protomers
can be related to the structure of caffeine metabolites and facilitate
the identification of the structural isomers.
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Affiliation(s)
- Helen Sepman
- Department of Materials and Environmental Chemistry, Stockholm University, Svante Arrhenius väg 16, 106 91 Stockholm, Sweden
| | - Sofja Tshepelevitsh
- Institute of Chemistry, University of Tartu, Ravila 14a, Tartu 50411, Estonia
| | - Henrik Hupatz
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 20, 14195 Berlin, Germany
| | - Anneli Kruve
- Department of Materials and Environmental Chemistry, Stockholm University, Svante Arrhenius väg 16, 106 91 Stockholm, Sweden
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9
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Remmerswaal WA, Houthuijs KJ, van de Ven R, Elferink H, Hansen T, Berden G, Overkleeft HS, van der Marel GA, Rutjes FPJT, Filippov DV, Boltje TJ, Martens J, Oomens J, Codée JDC. Stabilization of Glucosyl Dioxolenium Ions by "Dual Participation" of the 2,2-Dimethyl-2-( ortho-nitrophenyl)acetyl (DMNPA) Protection Group for 1,2- cis-Glucosylation. J Org Chem 2022; 87:9139-9147. [PMID: 35748115 PMCID: PMC9295149 DOI: 10.1021/acs.joc.2c00808] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
![]()
The stereoselective
introduction of glycosidic bonds is of paramount
importance to oligosaccharide synthesis. Among the various chemical
strategies to steer stereoselectivity, participation by either neighboring
or distal acyl groups is used particularly often. Recently, the use
of the 2,2-dimethyl-2-(ortho-nitrophenyl)acetyl (DMNPA)
protection group was shown to offer enhanced stereoselective steering
compared to other acyl groups. Here, we investigate the origin of
the stereoselectivity induced by the DMNPA group through systematic
glycosylation reactions and infrared ion spectroscopy (IRIS) combined
with techniques such as isotopic labeling of the anomeric center and
isomer population analysis. Our study indicates that the origin of
the DMNPA stereoselectivity does not lie in the direct participation
of the nitro moiety but in the formation of a dioxolenium ion that
is strongly stabilized by the nitro group.
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Affiliation(s)
- Wouter A Remmerswaal
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Kas J Houthuijs
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Roel van de Ven
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Hidde Elferink
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Thomas Hansen
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands.,Departament de Química Inorgànica i Orgànica & IQTUB, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Giel Berden
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Herman S Overkleeft
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Gijsbert A van der Marel
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Floris P J T Rutjes
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Dmitri V Filippov
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Thomas J Boltje
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Jonathan Martens
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Jos Oomens
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Jeroen D C Codée
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
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10
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Oluwatoba DS, Islam MF, Som B, Sindt AJ, Smith MD, Shimizu LS, Do TD. Evaluating the Effects of Metal Adduction and Charge Isomerism on Ion-Mobility Measurements using m-Xylene Macrocycles as Models. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:840-850. [PMID: 35471025 DOI: 10.1021/jasms.2c00033] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Gas-phase ion-mobility spectrometry provides a unique platform to study the effect of mobile charge(s) or charge location on collisional cross section and ion separation. Here, we evaluate the effects of cation/anion adduction in a series of xylene and pyridyl macrocycles that contain ureas and thioureas. We explore how zinc binding led to unexpected deprotonation of the thiourea macrocyclic host in positive polarity ionization and subsequently how charge isomerism due to cation (zinc metal) and anion (chloride counterion) adduction or proton competition among acceptors can affect the measured collisional cross sections in helium and nitrogen buffer gases. Our approach uses synthetic chemistry to design macrocycle targets and a combination of ion-mobility spectrometry mass spectrometry experiments and quantum mechanics calculations to characterize their structural properties. We demonstrate that charge isomerism significantly improves ion-mobility resolution and allows for determination of the metal binding mechanism in metal-inclusion macrocyclic complexes. Additionally, charge isomers can be populated in molecules where individual protons are shared between acceptors. In these cases, interactions via drift gas collisions magnify the conformational differences. Finally, for the macrocyclic systems we report here, charge isomers are observed in both helium and nitrogen drift gases with similar resolution. The separation factor does not simply increase with increasing drift gas polarizability. Our study sheds light on important properties of charge isomerism and offers strategies to take advantage of this phenomenon in analytical separations.
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Affiliation(s)
- Damilola S Oluwatoba
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Md Faizul Islam
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Bozumeh Som
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
- Department of Chemistry, University of Ghana, P.O. Box LG 56, Legon, Accra, Ghana
| | - Ammon J Sindt
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Mark D Smith
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Linda S Shimizu
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Thanh D Do
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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11
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Hirata K, Haddad F, Dopfer O, Ishiuchi SI, Fujii M. Collision-assisted stripping for determination of microsolvation-dependent protonation sites in hydrated clusters by cryogenic ion trap infrared spectroscopy: the case of benzocaineH +(H 2O) n. Phys Chem Chem Phys 2022; 24:5774-5779. [PMID: 35199812 DOI: 10.1039/d1cp05762f] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The protonation site of molecules can be varied by their surrounding environment. Gas-phase studies, including the popular techniques of infrared spectroscopy and ion mobility spectrometry, are a powerful tool for the determination of protonation sites in solvated clusters but often suffer from inherent limits for larger hydrated clusters. Here, we present collision-assisted stripping infrared (CAS-IR) spectroscopy as a new technique to overcome these problems and apply it in a proof-of-principle experiment to hydrated clusters of protonated benzocaine (H+BC), which shows protonation-site switching depending on the degree of hydration. The most stable protomer of H+BC in the gas phase (O-protonated) is interconverted into its most stable protomer in aqueous solution (N-protonated) upon hydration with three water molecules. CAS-IR spectroscopy enables us to unambiguously assign protonation sites and quantitatively determine the relative abundance of various protomers.
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Affiliation(s)
- Keisuke Hirata
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan. .,Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.,Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, 4259, Yokohama, 226-8503, Japan.
| | - Fuad Haddad
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, Berlin 10623, Germany
| | - Otto Dopfer
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, 4259, Yokohama, 226-8503, Japan. .,Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, Berlin 10623, Germany
| | - Shun-Ichi Ishiuchi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan. .,Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.,Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, 4259, Yokohama, 226-8503, Japan.
| | - Masaaki Fujii
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan. .,Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, 4259, Yokohama, 226-8503, Japan. .,School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8503, Japan
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12
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Ucur B, Maccarone AT, Ellis SR, Blanksby SJ, Trevitt AJ. Solvent-Mediated Proton-Transfer Catalysis of the Gas-Phase Isomerization of Ciprofloxacin Protomers. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:347-354. [PMID: 35014802 DOI: 10.1021/jasms.1c00331] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Understanding how neutral molecules become protonated during positive-ion electrospray ionization (ESI) mass spectrometry is critically important to ensure analytes can be efficiently ionized, detected, and unambiguously identified. The ESI solvent is one of several parameters that can alter the dominant site of protonation in polyfunctional molecules and thus, in turn, can significantly change the collision-induced dissociation (CID) mass spectra relied upon for compound identification. Ciprofloxacin─a common fluoroquinolone antibiotic─is one such example whereby positive-ion ESI can result in gas-phase [M + H]+ ions protonated at either the keto-oxygen or the piperazine-nitrogen. Here, we demonstrate that these protonation isomers (or protomers) of ciprofloxacin can be resolved by differential ion mobility spectrometry and give rise to distinctive CID mass spectra following both charge-directed and charge-remote mechanisms. Interaction of mobility-selected protomers with methanol vapor (added via the throttle gas supply) was found to irreversibly convert the piperazine N-protomer to the keto-O-protomer. This methanol-mediated proton-transport catalysis is driven by the overall exothermicity of the reaction, which is computed to favor the O-protomer by 93 kJ mol-1 (in the gas phase). Conversely, gas phase interactions of mobility-selected ions with acetonitrile vapor selectively depletes the N-protomer ion signal as formation of stable [M + H + CH3CN]+ cluster ions skews the apparent protomer population ratio, as the O-protomer is unaffected. These findings provide a mechanistic basis for tuning protomer populations to ensure faithful characterization of multifunctional molecules by tandem mass spectrometry.
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Affiliation(s)
- Boris Ucur
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Alan T Maccarone
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Shane R Ellis
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, New South Wales 2522, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane 4001, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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13
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Carlo MJ, Patrick AL. Infrared multiple photon dissociation (IRMPD) spectroscopy and its potential for the clinical laboratory. J Mass Spectrom Adv Clin Lab 2022; 23:14-25. [PMID: 34993503 PMCID: PMC8713122 DOI: 10.1016/j.jmsacl.2021.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 12/09/2021] [Accepted: 12/09/2021] [Indexed: 11/29/2022] Open
Abstract
Infrared multiple photon dissociation (IRMPD) spectroscopy is a powerful tool used to probe the vibrational modes-and, by extension, the structure-of an ion within an ion trap mass spectrometer. Compared to traditional FTIR spectroscopy, IRMPD spectroscopy has advantages including its sensitivity and its relative ability to handle complex mixtures. While IRMPD has historically been a technique for fundamental analyses, it is increasingly being applied in a more analytical fashion. Notable recent demonstrations pertinent to the clinical laboratory and adjacent interests include analysis of modified amino acids/residues and carbohydrates, structural elucidation (including isomeric differentiation) of metabolites, identification of novel illicit drugs, and structural studies of various biomolecules and pharmaceuticals. Improvements in analysis time, coupling to commercial instruments, and integration with separations methods are all drivers toward the realization of these analytical applications. Additional improvements in these areas, along with advances in benchtop tunable IR sources and increased cross-discipline collaboration, will continue to drive innovation and widespread adoption. The goal of this tutorial article is to briefly present the fundamentals and instrumentation of IRMPD spectroscopy, as an overview of the utility of this technique for helping to answer questions relevant to clinical analysis, and to highlight limitations to widespread adoption, as well as promising directions in which the field may be heading.
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Key Words
- 2-AEP, 2-aminoethylphosphonic acid
- 2P1EA, 2-phenyl-1-ethanolamine
- CIVP, cryogenic ion vibrational predissociation spectroscopy
- CLIO, Centre Laser Infrarouge d’Orsay
- DFT, density functional theory
- FA, fluoroamphetamine
- FEL, free electron laser
- FELIX, Free Electron Laser for Infrared eXperiments
- FMA, fluoromethamphetamine
- FTICR, Fourier transform ion cyclotron resonance
- GC–MS, gas chromatography-mass spectrometry
- GSNO, S- nitro glutathione
- GlcNAc, n-Acetylglucosamine
- IR, infrared
- IR2MS3, infrared-infrared double-resonance multi-stage mass spectrometry
- IRMPD, infrared multiple photon dissociation (IRMPD)
- IRMPD-MS, infrared multiple photon dissociation spectroscopy mass spectrometry
- IRPD, infrared predissociation spectroscopy
- IVR, intramolecular vibrational redistribution
- Infrared multiple photon dissociation spectroscopy
- LC, liquid chromatography
- LC-MS, liquid chromatography-mass spectrometry
- LC-MS/MS, liquid chromatography-tandem mass spectrometry
- MDA, methylenedioxyamphetamine
- MDMA, methylenedioxymethamphetamine
- MMC, methylmethcathinone
- MS/MS, tandem mass spectrometry
- MSn, multi-stage mass spectrometry
- Mass spectrometry
- Metabolites
- NANT, N-acetyl-N-nitrosotryptophan
- OPO/A, optical parametric oscillator/amplifier
- PTM, post-translational modification
- Pharmaceuticals
- Post-translational modifications
- SNOCys, S-nitrosocysteine
- UV, ultraviolet
- UV-IR, ultraviolet-infrared
- Vibrational spectroscopy
- cw, continuous wave
- α-PVP, alpha-pyrrolidinovalerophenone
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Affiliation(s)
- Matthew J. Carlo
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA
| | - Amanda L. Patrick
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA
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14
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Corinti D, Chiavarino B, Spano M, Tintaru A, Fornarini S, Crestoni ME. Molecular Basis for the Remarkably Different Gas-Phase Behavior of Deprotonated Thyroid Hormones Triiodothyronine (T3) and Reverse Triiodothyronine (rT3): A Clue for Their Discrimination? Anal Chem 2021; 93:14869-14877. [PMID: 34714056 PMCID: PMC8581966 DOI: 10.1021/acs.analchem.1c03892] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Thyroid hormones
are biologically active small molecules responsible
for growth and development regulation, basal metabolic rate, and lipid
and carbohydrate metabolism. Liquid chromatography mass spectrometry
(LC–MS) can be used to quantify thyroid hormones blood level
with high speed and selectivity, aiming to improve the diagnosis and
treatment of the severe pathological conditions in which they are
implicated, i.e., hypo- and hyperthyroidism. In this work, the gas-phase
behavior of the isomeric thyroid hormones triiodothyronine (T3) and
reverse triiodothyronine (rT3) in their deprotonated form was studied
at a molecular level using MS-based techniques. Previously reported
collision-induced dissociation experiments yielded distinct spectra
despite the high structural similarity of the two compounds, suggesting
different charge sites to be responsible. Infrared multiple photon
dissociation spectroscopy on [T3-H]− and [rT3-H]− was performed, and the results were interpreted using
DFT and MP2 calculations, assessing the prevalence of T3 in the carboxylate
form and rT3 as a phenolate isomer. The different deprotonation sites
of the two isomers were also found to drive their ion-mobility behavior.
In fact, [T3-H]− and [rT3-H]− were
successfully separated. Drift times were correlated with collisional
cross section values of 209 and 215 Å2 for [T3-H]− and [rT3-H]−, respectively. Calculations
suggested the charge site to be the main parameter involved in the
different mobilities of the two anions. Finally, bare [T3-H]− and [rT3-H]− were made to react with neutral acetylacetone
and trifluoroacetic acid, confirming rT3 to be more acidic than T3
in agreement with the calculated gas-phase acidities of T3 and rT3
equal to 1345 and 1326 kJ mol–1, respectively.
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Affiliation(s)
- Davide Corinti
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza", Roma I-00185, Italy
| | - Barbara Chiavarino
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza", Roma I-00185, Italy
| | - Mattia Spano
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza", Roma I-00185, Italy
| | - Aura Tintaru
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire, UMR 7273, Marseille 13397, France
| | - Simonetta Fornarini
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza", Roma I-00185, Italy
| | - Maria Elisa Crestoni
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza", Roma I-00185, Italy
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15
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Chen L, Fournier JA. Probing Hydrogen-Bonding Interactions within Phenol-Benzimidazole Proton-Coupled Electron Transfer Model Complexes with Cryogenic Ion Vibrational Spectroscopy. J Phys Chem A 2021; 125:9288-9297. [PMID: 34652915 DOI: 10.1021/acs.jpca.1c05879] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hydrogen-bonding interactions within a series of phenol-benzimidazole model proton-coupled electron transfer (PCET) dyad complexes are characterized using cryogenic ion vibrational spectroscopy. A highly red-shifted and surprisingly broad (>1000 cm-1) transition is observed in one of the models and assigned to the phenolic OH stretch strongly H-bonded to the N(3) benzimidazole atom. The breadth is attributed to a combination of anharmonic Fermi-resonance coupling between the OH stretch and background doorway states involving OH bending modes and strong coupling of the OH stretch frequency to structural deformations along the proton-transfer coordinate accessible at the vibrational zero-point level. The other models show unexpected protonation of the benzimidazole group upon electrospray ionization instead of at more basic remote amine/amide groups. This leads to the formation of HO-+HN(3) H-bond motifs that are much weaker than the OH-N(3) H-bond arrangement. H-bonding between the N(1)H+ benzimidazole group and the carbonyl on the tyrosine backbone is the stronger and preferred interaction in these complexes. The results show that conjugation effects, secondary H-bond interactions, and H-bond soft modes strongly influence the OH-N(3) interaction and highlight the importance of the direct monitoring of proton stretch transitions in characterizing the proton-transfer reaction coordinate in PCET systems.
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Affiliation(s)
- Liangyi Chen
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Joseph A Fournier
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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16
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Mashmoushi N, Juhász DR, Coughlan NJA, Schneider BB, Le Blanc JCY, Guna M, Ziegler BE, Campbell JL, Hopkins WS. UVPD Spectroscopy of Differential Mobility-Selected Prototropic Isomers of Rivaroxaban. J Phys Chem A 2021; 125:8187-8195. [PMID: 34432451 DOI: 10.1021/acs.jpca.1c05564] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two ion populations of protonated Rivaroxaban, [C19H18ClN3O5S + H]+, are separated under pure N2 conditions using differential mobility spectrometry prior to characterization in a hybrid triple quadrupole linear ion trap mass spectrometer. These populations are attributed to bare protonated Rivaroxaban and to a proton-bound Rivaroxaban-ammonia complex, which dissociates prior to mass-selecting the parent ion. Ultraviolet photodissociation (UVPD) and collision-induced dissociation (CID) studies indicate that both protonated Rivaroxaban ion populations are comprised of the computed global minimum prototropic isomer. Two ion populations are also observed when the collision environment is modified with 1.5% (v/v) acetonitrile. In this case, the protonated Rivaroxaban ion populations are produced by the dissociation of the ammonium complex and by the dissociation of a proton-bound Rivaroxaban-acetonitrile complex prior to mass selection. Again, both populations exhibit a similar CID behavior; however, UVPD spectra indicate that the two ion populations are associated with different prototropic isomers. The experimentally acquired spectra are compared with computed spectra and are assigned to two prototropic isomers that exhibit proton sharing between distal oxygen centers.
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Affiliation(s)
- Nour Mashmoushi
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.,Waterloo Institute for Nanotechnology, University of 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Daniel R Juhász
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Neville J A Coughlan
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.,Waterloo Institute for Nanotechnology, University of 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | | | | | - Mircea Guna
- SCIEX, 71 Four Valley Drive, Concord, Ontario L4K 4V8, Canada
| | - Blake E Ziegler
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.,Watermine Innovation, Waterloo, Ontario N0B 2T0, Canada
| | - J Larry Campbell
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.,Watermine Innovation, Waterloo, Ontario N0B 2T0, Canada.,Bedrock Scientific, Milton, Ontario L6T 6J9, Canada
| | - W Scott Hopkins
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.,Waterloo Institute for Nanotechnology, University of 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.,Watermine Innovation, Waterloo, Ontario N0B 2T0, Canada.,Centre for Eye and Vision Research, New Territories 999077, Hong Kong
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17
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Coughlan NJA, Fu W, Guna M, Schneider BB, Le Blanc JCY, Campbell JL, Hopkins WS. Electronic spectroscopy of differential mobility-selected prototropic isomers of protonated para-aminobenzoic acid. Phys Chem Chem Phys 2021; 23:20607-20614. [PMID: 34505849 DOI: 10.1039/d1cp02120f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
para-Aminobenzoic acid (PABA) was electrosprayed from mixtures of protic and aprotic solvents, leading to formation of two prototropic isomers in the gas phase whose relative populations depended on the composition of the electrospray solvent. The two ion populations were separated in the gas phase using differential mobility spectrometry (DMS) within a nitrogen-only environment at atmospheric pressure. Under high-field conditions, the two prototropic isomers eluted with baseline signal separation with the N-protonated isomer having a more negative CV shift than the O-protonated isomer, in accord with previous DMS studies. The conditions most favorable for formation and separation of each tautomer were used to trap each prototropic isomer in a quadrupole ion trap for photodissociation action spectroscopy experiments. Spectral interrogation of each prototropic isomer in the UV region (3-6 eV) showed good agreement with previously recorded spectra, although a previously reported band (4.8-5.4 eV) was less intense for the O-protonated isomer in our measured spectrum. Without DMS selection, the measured spectra contained features corresponding to both protonated isomers even when solvent conditions were optimised for formation of a single isomer. Interconversion between protonated isomers within the ion trap was observed when protic ESI solvents were employed, leading to spectral cross contamination even with mobility selection. CCSD vertical excitation energies and vertical gradient (VG) Franck-Condon simulations are presented and reproduce the measured spectral features with near-quantitative agreement, providing supporting evidence for spectral assignments.
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Affiliation(s)
- Neville J A Coughlan
- 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
| | - Weiqiang Fu
- 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
| | - Mircea Guna
- SCIEX, Four Valley Drive, Concord, Ontario, L4K 4V8, Canada
| | | | | | - J Larry Campbell
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada. .,Bedrock Scientific Inc., Milton, Ontario, Canada.,WaterMine Innovation, Waterloo, Ontario, 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, Canada.,Centre for Eye and Vision Research, Hong Kong Science Park, New Territories, Hong Kong
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18
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Batista PR, Penna TC, Ducati LC, Correra TC. p-Aminobenzoic acid protonation dynamics in an evaporating droplet by ab initio molecular dynamics. Phys Chem Chem Phys 2021; 23:19659-19672. [PMID: 34524295 DOI: 10.1039/d1cp01495a] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Protonation equilibria are known to vary from the bulk to microdroplet conditions, which could induce many chemical and physical phenomena. Protonated p-aminobenzoic acid (PABA + H+) can be considered a model for probing the protonation dynamics in an evaporating droplet, as its protonation equilibrium is highly dependent on the formation conditions from solution via atmospheric pressure ionization sources. Experiments using diverse experimental techniques have shown that protic solvents allow formation of the O-protomer (PABA protonated in the carboxylic acid group) stable in the gas phase, while aprotic solvents yield the N-protomer (protonated in the amino group) that is the most stable protomer in solution. In this work, we explore the protonation equilibrium of PABA solvated by different numbers of water molecules (n = 0 to 32) using ab initio molecular dynamics. For n = 8-32, the protonation is either at the NH2 group or in the solvent network. The solvent network interacts with the carboxylic acid group, but there is no complete proton transfer to form the O-protomer. For smaller clusters, however, solvent-mediated proton transfers to the carboxylic acid were observed, both via the Grotthuss mechanism and the vehicle or shuttle mechanism (for n = 1 and 2). Thermodynamic considerations allowed a description of the origins of the kinetic trapping effect, which explains the observation of the solution structure in the gas phase. This effect likely occurs in the final evaporation steps, which are outside the droplet size range covered by previous classical molecular dynamics simulations of charged droplets. These results may be considered relevant in determining the nature of the species observed in the ubiquitous ESI based mass spectrometry analysis, and in general for droplet chemistry, explaining how protonation equilibria are drastically changed from bulk to microdroplet conditions.
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Affiliation(s)
- Patrick R Batista
- Department of Fundamental Chemistry, Institute of Chemistry - University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil.
| | - Tatiana C Penna
- Department of Fundamental Chemistry, Institute of Chemistry - University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil.
| | - Lucas C Ducati
- Department of Fundamental Chemistry, Institute of Chemistry - University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil.
| | - Thiago C Correra
- Department of Fundamental Chemistry, Institute of Chemistry - University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil.
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19
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Demireva M, Armentrout PB. Relative Energetics of the Gas Phase Protomers of p-Aminobenzoic Acid and the Effect of Protonation Site on Fragmentation. J Phys Chem A 2021; 125:2849-2865. [DOI: 10.1021/acs.jpca.0c11540] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Maria Demireva
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - P. B. Armentrout
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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20
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Zheng Z, Attygalle AB. Impact of Ambient Vapors Present in an Electrospray Ionization Source on Gas-Phase Ion Structures. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:725-735. [PMID: 33606934 DOI: 10.1021/jasms.0c00430] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
According to current consensus, structures of protomeric (or deprotomeric) tautomers of gaseous ions generated by electrospray ionization depend primarily on the nature of the spray solvent. To probe the effect of the spray solvent on protonation, 4-aminobenzoic acid (PABA) has often been selected as the model compound. It is widely accepted that the protonation in the gas phase takes place primarily on the carbonyl oxygen atom when the sample is sprayed in methanol and on the nitrogen atom when acetonitrile is used as the spray solvent. Although this observation is valid, our current results indicate that the determination of the predominant protomer in the gas phase by the spray solvent is an indirect effect moderated by the solvent vapor molecules present in the ambient ion source. To investigate real-time changes in protomer distributions due to solvents, we used ion-mobility mass spectrometry (IM-MS). Initially, when a PABA solution in methanol was electrosprayed, the ion-mobility arrival-time profile recorded showed essentially one peak for the O-protomer. However, when acetonitrile or acetone vapors were introduced to the ambient-pressure ion source via the flowing desolvation gas, the intensity of the O-protomer peak diminished rapidly, and the N-protomer signal became dominant. The moment the acetonitrile (or acetone) vapors were removed from the ion source, the protomer-distribution signals began gradually reverting back to their original intensities. Furthermore, when PABA samples in methanol and acetonitrile were electrosprayed separately via a dual-sprayer setup, which allowed for the selective blocking of the gaseous ion-generation cascade of charged droplets from either sprayer, the predominant signal corresponded only to the N-protomer, irrespective of the position of the mechanical barrier. Because the mechanical barrier prevents only the gaseous ion formation, but not the physical access of solvent vapors to the ion source, it is evident that the solvent vapor that engulfs the ion source is the governing factor that decides the protomer distribution, not the nature of the spray solvent. Noticeably, acetonitrile wields a stronger effect on the manifested protomer distribution than many other solvents, including methanol, water, hexanes, and toluene. Apparently, the so-called "memory" of the solution-phase structures and the phenomenon described as "kinetic trapping" are both due to indirect effects caused by the solvent vapor engulfing the atmospheric-pressure ion source. Moreover, the so-called "memory" effect can either be "saved" or "erased" by exposing the initially formed gaseous ions to different solvent vapors from an alternative source.
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Affiliation(s)
- Zhaoyu Zheng
- Center for Mass Spectrometry, Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - Athula B Attygalle
- Center for Mass Spectrometry, Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
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21
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Marlton SJP, McKinnon BI, Hill NS, Coote ML, Trevitt AJ. Electrostatically Tuning the Photodissociation of the Irgacure 2959 Photoinitiator in the Gas Phase by Cation Binding. J Am Chem Soc 2021; 143:2331-2339. [PMID: 33427467 DOI: 10.1021/jacs.0c11978] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The low-lying electronic states of Irgacure 2959, a Norrish-type I photoinitiator, complexed with a single metal cation are investigated in the gas phase by photodissociation action spectroscopy. Analysis of the band shifts using quantum chemical calculations (TD-DFT and SCS-CC2) reveals the underlying influence of the charge on the key electronic energy levels. Since the cations (H+, Li+, Na+, K+, Zn2+, Ca2+, and Mg2+) bind at varying distances, the magnitude of the electric field at the center of the chromophore due to the cation is altered, and this shifts the electronic states by different amounts. Photodissociation action spectra of cation-Irg complexes show that absorption transitions to the first 1ππ* state are red-shifted with a magnitude proportional to the electric field strength (with red shifts >1 eV), and in most cases, the cation is essentially acting as a point charge. Calculations show that a neighboring 3nπ* state, a key state for the α-cleavage pathway, is destabilized (blue-shifted) by the orientated electric field. As such, if the 1ππ*-3nπ* energy gap is reduced, increased intersystem crossing rates are expected, resulting in higher yields of the desired radical photoproducts, and this is controlled by the orientated electric field arising from the cation.
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Affiliation(s)
- Samuel J P Marlton
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Benjamin I McKinnon
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Nicholas S Hill
- ARC Centre of Excellence for Electromaterials Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Michelle L Coote
- ARC Centre of Excellence for Electromaterials Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
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22
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Saparbaev E, Aladinskaia V, Zviagin A, Boyarkin OV. Microhydration of Biomolecules: Revealing the Native Structures by Cold Ion IR Spectroscopy. J Phys Chem Lett 2021; 12:907-911. [PMID: 33439655 DOI: 10.1021/acs.jpclett.0c03678] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The native-like structures of protonated glycine and peptide Gly3H+ were elucidated using cold ion IR spectroscopy of these biomolecules hydrated by a controlled number of water molecules. The complexes were generated directly from an aqueous solution using gentle electrospray ionization. Already with a single retained water molecule, GlyH+ exhibits the native-like structure characterized by a lack of intramolecular hydrogen bonds. We use our spectra to calibrate the available data for the same complexes, which are produced by cryogenic condensation of water onto the gas-phase glycine. In some conformers of these complexes, GlyH+ adopts the native-like structure, while in the others, it remains "kinetically" trapped in the intrinsic state. Upon condensation of 4-5 water molecules, the embedded amino acid fully adopts its native-like structure. Similarly, condensation of one water molecule onto the tripeptide is insufficient to fully eliminate its kinetically trapped intrinsic states.
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Affiliation(s)
- Erik Saparbaev
- Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne, Station-6, 1015 Lausanne, Switzerland
| | - Viktoriia Aladinskaia
- Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne, Station-6, 1015 Lausanne, Switzerland
| | - Andrei Zviagin
- Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne, Station-6, 1015 Lausanne, Switzerland
| | - Oleg V Boyarkin
- Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne, Station-6, 1015 Lausanne, Switzerland
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23
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van Geenen FAMG, Kranenburg RF, van Asten AC, Martens J, Oomens J, Berden G. Isomer-Specific Two-Color Double-Resonance IR 2MS 3 Ion Spectroscopy Using a Single Laser: Application in the Identification of Novel Psychoactive Substances. Anal Chem 2021; 93:2687-2693. [PMID: 33470107 PMCID: PMC7859929 DOI: 10.1021/acs.analchem.0c05042] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
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The capability of
an ion trap mass
spectrometer to store ions for
an arbitrary amount of time allows the use of a single infrared (IR)
laser to perform two-color double resonance IR–IR spectroscopic
experiments on mass-to-charge (m/z) selected ions. In this single-laser IR2MS3 scheme, one IR laser frequency is used to remove a selected set
of isomers from the total trapped ion population and the second IR
laser frequency, from the same laser, is used to record the IR spectrum
of the remaining precursor ions. This yields isomer-specific vibrational
spectra of the m/z-selected ions,
which can reveal the structure and identity of the initially co-isolated
isomeric species. The use of a single laser greatly reduces the experimental
complexity of two-color IR2MS3 and enhances
its application in fields employing analytical MS. In this work, we
demonstrate the methodology by acquiring single-laser IR2MS3 spectra in a forensic context, identifying two previously
unidentified isomeric novel psychoactive substances (NPS) from a sample
that was confiscated by the Amsterdam Police.
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Affiliation(s)
- Fred A M G van Geenen
- FELIX Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Ruben F Kranenburg
- Forensic Laboratory, Unit Amsterdam, Dutch National Police, Kabelweg 25, 1014 BA Amsterdam, The Netherlands.,Van't Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands
| | - Arian C van Asten
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands.,Co van Ledden Hulsebosch Center (CLHC), Amsterdam Center for Forensic Science and Medicine, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands
| | - Jonathan Martens
- FELIX Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Jos Oomens
- FELIX Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands.,Van't Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands
| | - Giel Berden
- FELIX Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
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24
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Lermyte F, Theisen A, O'Connor PB. Solution Condition-Dependent Formation of Gas-Phase Protomers of Alpha-Synuclein in Electrospray Ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:364-372. [PMID: 33237779 DOI: 10.1021/jasms.0c00373] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
One of the main characteristics of biomolecular ions in mass spectrometry is their net charge, and a range of approaches exist to either increase or decrease this quantity in the gas phase. In the context of small molecules, it is well known that, in addition to the charge state, the charge site also has a profound effect on an ion's gas-phase behavior; however, this effect has been far less explored for peptides and intact proteins. Methods exist to determine charge sites of protein ions, and others have observed that the interplay of electrostatic repulsion and inherent basicity leads to different sites gaining or losing a charge depending on the total net charge. Here, we report two distinct protonation site isomers ("protomers") of α-synuclein occurring at the same charge state. The protomers showed important differences in their gas-phase fragmentation behavior and were furthermore distinguishable by ion mobility spectrometry. One protomer was produced under standard electrospray conditions, while the other was observed after addition of 10% dimethyl sulfoxide to the protein solution. Charge sites for both protomers were determined using ultraviolet photodissociation.
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Affiliation(s)
- Frederik Lermyte
- Department of Chemistry, Technical University of Darmstadt, 64287 Darmstadt, Germany
- School of Engineering, University of Warwick, Coventry CV4 7AL, U.K
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Alina Theisen
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Peter B O'Connor
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
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25
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Khuu T, Yang N, Johnson MA. Vibrational spectroscopy of the cryogenically cooled O- and N-protomers of 4-Aminobenzoic acid: Tag effects, isotopic labels, and identification of the E,Z isomer of the O-protomer. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2020; 457:116427. [PMID: 32982573 PMCID: PMC7511085 DOI: 10.1016/j.ijms.2020.116427] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
4-Aminobenzoic acid (4ABA) is a biologically relevant, small organic molecule with two protonation sites: the amino group (N-protomer) and the carboxyl group (O-protomer). The O-protomer is energetically preferred in the gas-phase, while the higher energy N-protomer can be trapped using aprotic solvents such as acetonitrile during electrospray ionization. Here, we focus on the structure of the O-protomer, which can occur in three low-lying isomeric forms that result from different orientations of the OH groups relative to the benzene ring. We report the vibrational spectra of both N- and O-protomers of the cryogenically cooled ions in the gas phase over the spectral range 800-4000 cm-1. The bands arising from the OH stretches are isolated from the nearby NH stretching fundamentals using isotopic labeling as well as by analysis of the shifts in these fundamentals upon attachment of D2 and N2 molecules to the OH groups of the O-protomer. The spectra of isomers derived from the different locations of the adducts were isolated using two-color, IR-IR photofragmentation spectroscopy. The docking motifs by which the O-protomer binds to another 4ABA molecule is also explored and found to feature a bifurcated arrangement involving attachment of both OH groups of the protonated head group to the carbonyl group of the neutral partner.
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Affiliation(s)
- Thien Khuu
- Sterling Chemistry Laboratory, Yale University, New Haven, CT, 06520
| | - Nan Yang
- Sterling Chemistry Laboratory, Yale University, New Haven, CT, 06520
| | - Mark A Johnson
- Sterling Chemistry Laboratory, Yale University, New Haven, CT, 06520
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26
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Kumar R, Kenttämaa HI. Effects of Analyte Concentration on the Protonation Sites of 4-Aminobenzoic Acid upon Atmospheric Pressure Chemical Ionization As Revealed by Gas-Phase Ion-Molecule Reactions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:2210-2217. [PMID: 32852952 DOI: 10.1021/jasms.0c00285] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The most basic site of 4-aminobenzoic acid in aqueous solution is the amino nitrogen, while the carbonyl oxygen is calculated to be the most basic site in the gas phase. However, the preferred protonation site of 4-aminobenzoic acid upon electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) depends upon the ionization solvent and ion source parameters. The influence of the concentration of the analyte on the manifested protonation sites upon APCI has not been investigated and is reported here. Gas-phase ion-molecule reactions of trimethoxymethylsilane were used to identify the protonation sites of 4-aminobenzoic acid ionized using APCI with methanol or acetonitrile-water as the solvent. The nitrogen-protomer was found to be about twice as abundant as the oxygen-protomer at low analyte concentrations (10-9-10-6 M) in methanol solvent. This finding was rationalized on the basis of a previous finding that when the O-protomer is surrounded by more than eight methanol molecules in the gas phase it starts behaving as if it were in an aqueous solution and converts to the N-protomer. At greater analyte concentrations (≥10-4 M), the amino group was predominantly protonated, which was rationalized based on the formation of a particularly stable proton-bound dimer of 4-aminobenzoic acid that preferentially dissociates to form the N-protomer. The above findings suggest that solution processes are much more important in APCI than commonly assumed, in agreement with recent literature. Indeed, when 1:1 (v/v) acetonitrile-water was used as the solvent system for 4-aminobenzoic acid, the N-protomer was predominantly generated at all analyte concentrations.
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Affiliation(s)
- Rashmi Kumar
- Chemistry Department, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Hilkka I Kenttämaa
- Chemistry Department, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
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27
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Penna TC, Cervi G, Rodrigues-Oliveira AF, Yamada BD, Lima RZC, Menegon JJ, Bastos EL, Correra TC. Development of a photoinduced fragmentation ion trap for infrared multiple photon dissociation spectroscopy. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34 Suppl 3:e8635. [PMID: 31677291 DOI: 10.1002/rcm.8635] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/07/2019] [Accepted: 10/08/2019] [Indexed: 06/10/2023]
Abstract
RATIONALE Methods for isomer discrimination by mass spectroscopy are of increasing interest. Here we describe the development of a three-dimensional ion trap for infrared multiple photon dissociation (IRMPD) spectroscopy that enables the acquisition of the infrared spectrum of selected ions in the gas phase. This system is suitable for the study of a myriad of chemical systems, including isomer mixtures. METHODS A modified three-dimensional ion trap was coupled to a CO2 laser and an optical parametric oscillator/optical parametric amplifier (OPO/OPA) system operating in the range 2300 to 4000 cm-1 . Density functional theory vibrational frequency calculations were carried out to support spectral assignments. RESULTS Detailed descriptions of the interface between the laser and the mass spectrometer, the hardware to control the laser systems, the automated system for IRMPD spectrum acquisition and data management are presented. The optimization of the crystal position of the OPO/OPA system to maximize the spectroscopic response under low-power laser radiation is also discussed. CONCLUSIONS OPO/OPA and CO2 laser-assisted dissociation of gas-phase ions was successfully achieved. The system was validated by acquiring the IRMPD spectra of model species and comparing with literature data. Two isomeric alkaloids of high economic importance were characterized to demonstrate the potential of this technique, which is now available as an open IRMPD spectroscopy facility in Brazil.
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Affiliation(s)
- Tatiana C Penna
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
| | - Gustavo Cervi
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
| | - André F Rodrigues-Oliveira
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
| | - Bruno D Yamada
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
| | - Rafael Z C Lima
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
| | - Jair J Menegon
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
| | - Erick L Bastos
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
| | - Thiago C Correra
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
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28
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Marlton SJP, McKinnon BI, Ucur B, Bezzina JP, Blanksby SJ, Trevitt AJ. Discrimination between Protonation Isomers of Quinazoline by Ion Mobility and UV-Photodissociation Action Spectroscopy. J Phys Chem Lett 2020; 11:4226-4231. [PMID: 32368922 DOI: 10.1021/acs.jpclett.0c01009] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The influence of oriented electric fields on chemical reactivity and photochemistry is an area of increasing interest. Within a molecule, different protonation sites offer the opportunity to control the location of charge and thus orientation of electric fields. New techniques are thus needed to discriminate between protonation isomers in order to understand this effect. This investigation reports the UV-photodissociation action spectroscopy of two protonation isomers (protomers) of 1,3-diazanaphthalene (quinazoline) arising from protonation of a nitrogen at either the 1- or 3-position. It is shown that these protomers are separable by field-asymmetric ion mobility spectrometry (FAIMS) with confirmation provided by UV-photodissociation (PD) action spectroscopy. Vibronic features in the UVPD action spectra and computational input allow assignment of the origin transitions to the S1 and S5 states of both protomers. These experiments also provide vital benchmarks for protomer-specific calculations and examination of isomer-resolved reaction kinetics and thermodynamics.
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Affiliation(s)
- Samuel J P Marlton
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Benjamin I McKinnon
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Boris Ucur
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - James P Bezzina
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane 4001, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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29
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Hebert MJ, Russell DH. Tracking the Structural Evolution of 4-Aminobenzoic Acid in the Transition from Solution to the Gas Phase. J Phys Chem B 2020; 124:2081-2087. [DOI: 10.1021/acs.jpcb.9b10576] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Michael J. Hebert
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - David H. Russell
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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30
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Kumar R, Yerabolu R, Kenttämaa HI. Effects of Residual Water in a Linear Quadrupole Ion Trap on the Protonation Sites of 4-Aminobenzoic Acid. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:124-131. [PMID: 32881520 DOI: 10.1021/jasms.9b00001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In solution, the most basic site in 4-aminobenzoic acid is the amino nitrogen, while the carboxylic acid oxygen is the most basic site in the gas phase. However, the protonation site in the gas phase has been demonstrated to depend on the ionization solvents when ionized using positive ion mode electrospray ionization (ESI). In many of these studies, collision-activated dissociation (CAD) was used to differentiate the protomers. To explore the influence of different CAD conditions on the manifested protonation site, 4-aminobenzoic acid dissolved either in 1:1 acetonitrile-water or 3:1 methanol-water was ionized by ESI and subjected to three different CAD experiments in a linear quadrupole ion trap/orbitrap mass spectrometer. Based on in-source CAD (ISCAD) and beam-type medium-energy CAD (MCAD), the proton resided on the nitrogen atom (N-protomer) when acetonitrile-water was used as the solvent system but on the oxygen atom (O-protomer) when methanol-water was used. Interestingly, a predominant N-protomer was observed when CAD was performed in the linear quadrupole ion trap (ITCAD), irrespective of the solvents used, in disagreement with literature. This unexpected result is rationalized based on the formation of long-lived water clusters of varying sizes for the protomers in the quadrupole ion trap due to residual water, low ion kinetic energies, long ion storage times, and relatively high pressure. Further, addition of extra water into the quadrupole ion trap resulted in nearly identical protomer distributions for both protomers. Therefore, this distribution must be near the equilibrium distribution caused by the presence of water clusters of varying sizes, some favoring the N-protomer and others the O-protomer.
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Affiliation(s)
- Rashmi Kumar
- Chemistry Department, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Ravikiran Yerabolu
- Chemistry Department, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Hilkka I Kenttämaa
- Chemistry Department, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
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31
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Ohshimo K, Miyazaki S, Hattori K, Misaizu F. Long-distance proton transfer induced by a single ammonia molecule: ion mobility mass spectrometry of protonated benzocaine reacted with NH3. Phys Chem Chem Phys 2020; 22:8164-8170. [DOI: 10.1039/c9cp06923b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A long-distance proton transfer via the vehicle mechanism in the absence of a hydrogen-bonded solvent-bridge in molecules.
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Affiliation(s)
- Keijiro Ohshimo
- Department of Chemistry, Graduate School of Science
- Tohoku University
- Sendai 980-8578
- Japan
| | - Shun Miyazaki
- Department of Chemistry, Graduate School of Science
- Tohoku University
- Sendai 980-8578
- Japan
| | - Keigo Hattori
- Department of Chemistry, Graduate School of Science
- Tohoku University
- Sendai 980-8578
- Japan
| | - Fuminori Misaizu
- Department of Chemistry, Graduate School of Science
- Tohoku University
- Sendai 980-8578
- Japan
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32
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Chandran J, Zheng Z, Thomas VI, Rajalakshmi C, Attygalle AB. LC-MS analysis of p-aminosalicylic acid under electrospray ionization conditions manifests a profound solvent effect. Analyst 2020; 145:5333-5344. [DOI: 10.1039/d0an00680g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Under identical mass spectrometric conditions, chromatographic peak intensities of p-aminosalicylic acid recorded by LC-MS, using methanol as the mobile phase are drastically different from those acquired using is it acetonitrile as the eluent.
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Affiliation(s)
- Jisha Chandran
- Inter University Instrumentation Centre (IUIC)
- School of Environmental Sciences
- Mahatma Gandhi University
- Kottayam
- 686560 India
| | - Zhaoyu Zheng
- Center for Mass Spectrometry
- Department of Chemistry and Chemical Biology
- Stevens Institute of Technology
- Hoboken
- USA
| | | | | | - Athula B. Attygalle
- Center for Mass Spectrometry
- Department of Chemistry and Chemical Biology
- Stevens Institute of Technology
- Hoboken
- USA
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33
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Munshi MU, Martens J, Berden G, Oomens J. Protoisomerization of Indigo and Isoindigo Dyes Confirmed by Gas-Phase Infrared Ion Spectroscopy. J Phys Chem A 2019; 123:8226-8233. [PMID: 31490692 PMCID: PMC6767361 DOI: 10.1021/acs.jpca.9b06858] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
![]()
Gas-phase
infrared multiple-photon dissociation (IRMPD) spectra
are recorded for the protonated dye molecules indigo and isoindigo
by using a quadrupole ion trap (QIT) mass spectrometer coupled to
the free electron laser for infrared experiments (FELIX). From their
fingerprint IR spectra (600—1800 cm–1) and
comparison with quantum-chemical calculations at the density functional
level of theory (B3LYP/6-31++G(d,p)), we derive their structures.
We focus particularly on the question of whether trans-to-cis isomerization occurs upon protonation and
transfer to the gas phase. The trans-configuration
is energetically favored in the neutral forms of the dyes in solution
and in the gas phase. Instead, the cis-isomer is
lower in energy for the protonated forms of both species, but indigo
is also notorious for not undergoing double-bond trans-to-cis isomerization, in contrast to many other
conjugated systems. The IR spectra suggest that protoisomerization
from trans to cis indeed occurs
for both dyes. To estimate the extent of isomerization, on-resonance
kinetics are measured on diagnostic and common vibrational frequencies
to determine the ratio of cis-to-trans isomers. We find ratios of 65–70% cis and
30–35% trans for indigo versus 75–80% cis and 20–25% trans for isoindigo.
Transition-state calculations for the isomerization reactions have
been carried out, which indeed suggest a lower barrier for protonated
isoindigo, qualitatively explaining the more efficient isomerization.
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Affiliation(s)
- Musleh Uddin Munshi
- Institute for Molecules and Materials, FELIX Laboratory , Radboud University , Toernooiveld 7 , 6525 ED Nijmegen , The Netherlands
| | - Jonathan Martens
- Institute for Molecules and Materials, FELIX Laboratory , Radboud University , Toernooiveld 7 , 6525 ED Nijmegen , The Netherlands
| | - Giel Berden
- Institute for Molecules and Materials, FELIX Laboratory , Radboud University , Toernooiveld 7 , 6525 ED Nijmegen , The Netherlands
| | - Jos Oomens
- Institute for Molecules and Materials, FELIX Laboratory , Radboud University , Toernooiveld 7 , 6525 ED Nijmegen , The Netherlands.,University of Amsterdam , Science Park 904 , 1098XH Amsterdam , The Netherlands
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34
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M Ribeiro FW, Rodrigues-Oliveira AF, C Correra T. Benzoxazine Formation Mechanism Evaluation by Direct Observation of Reaction Intermediates. J Phys Chem A 2019; 123:8179-8187. [PMID: 31483645 DOI: 10.1021/acs.jpca.9b05065] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Benzoxazine formation is a fundamental step in the preparation of polybenzoxazine resins, and a detailed description of the mechanism governing the formation of benzoxazine and side products is vital for improving the properties and performance of these resins. Determination of the nature and properties of reaction intermediates is not trivial. Therefore, a Mannich-type condensation of aniline, formaldehyde, and phenol was evaluated as a potential method to form benzoxazine. Coupling positive mode electrospray ionization mass spectrometry (ESI(+)-MS) with infrared multiple photon dissociation (IRMPD) spectroscopy allowed unambiguous determination of an iminium-based mechanism and the direct observation of iminium intermediates. The benzoxazine formation mechanism was indirectly confirmed by the observation of side products that are relevant to the polymerization step, and directly confirmed by the identification of four distinct reaction intermediates that were completely characterized by IRMPD spectroscopy. The benzoxazine monomer was also shown to undergo isomerization under standard ESI-MS analysis conditions, suggesting the presence of a mixture of three isomers during their usual ESI-MS analysis.
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Affiliation(s)
- Francisco W M Ribeiro
- Department of Fundamental Chemistry, Institute of Chemistry , University of São Paulo Av. Prof. Lineu Prestes, 748, Cidade Universitária , São Paulo , São Paulo 05508-000 , Brazil
| | - André F Rodrigues-Oliveira
- Department of Fundamental Chemistry, Institute of Chemistry , University of São Paulo Av. Prof. Lineu Prestes, 748, Cidade Universitária , São Paulo , São Paulo 05508-000 , Brazil
| | - Thiago C Correra
- Department of Fundamental Chemistry, Institute of Chemistry , University of São Paulo Av. Prof. Lineu Prestes, 748, Cidade Universitária , São Paulo , São Paulo 05508-000 , Brazil
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35
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Corinti D, Maccelli A, Chiavarino B, Maitre P, Scuderi D, Bodo E, Fornarini S, Crestoni ME. Vibrational signatures of curcumin's chelation in copper(II) complexes: An appraisal by IRMPD spectroscopy. J Chem Phys 2019; 150:165101. [PMID: 31042893 DOI: 10.1063/1.5086666] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Curcumin (Cur) is a natural polyphenol with a wide spectrum of biological activities and appealing therapeutic potential. Herein, it has been delivered by electrospray ionization as gaseous protonated species, [Cur + H]+, and as a Cu(ii) complex, [Cu(Cur - H)]+, a promising antioxidant and radical scavenger. The gas phase structures were assayed by infrared multiple photon dissociation (IRMPD) spectroscopy in both the fingerprint (800-2000 cm-1) and hydrogen stretching (3100-3750 cm-1) ranges. Comparison between the experimental features and linear IR spectra of the lowest energy structures computed at the B3LYP/6-311+G(d,p) level reveals that bare [Cu(Cur - H)]+ exists in a fully planar and symmetric arrangement, where the metal interacts with the two oxygens of the syn-enolate functionality of deprotonated Cur and both OCH3 groups are engaged in H-bonding with the ortho OH. The effect of protonation on the energetic and geometric determinants of Cur has been explored as well, revealing that bare [Cur + H]+ may exist as a mixture of two close-lying isomers associated with the most stable binding motifs. The additional proton is bound to either the diketo or the keto-enol configuration of Cur, in a bent or nearly planar arrangement, respectively.
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Affiliation(s)
- Davide Corinti
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza," Piazzale Aldo Moro, 5, I-00185 Roma, Italy
| | - Alessandro Maccelli
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza," Piazzale Aldo Moro, 5, I-00185 Roma, Italy
| | - Barbara Chiavarino
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza," Piazzale Aldo Moro, 5, I-00185 Roma, Italy
| | - Philippe Maitre
- Laboratoire de Chimie Physique (UMR8000), CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
| | - Debora Scuderi
- Laboratoire de Chimie Physique (UMR8000), CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
| | - Enrico Bodo
- Dipartimento di Chimica, Università di Roma "La Sapienza," Piazzale Aldo Moro, 5, I-00185 Roma, Italy
| | - Simonetta Fornarini
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza," Piazzale Aldo Moro, 5, I-00185 Roma, Italy
| | - Maria Elisa Crestoni
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza," Piazzale Aldo Moro, 5, I-00185 Roma, Italy
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36
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Xiao HM, Wang X, Yang X, Zheng F, Feng YQ. Hydralazine derivative of aldehyde: A new type of [M - H] + ion formed in electrospray ionization mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2019; 54:239-249. [PMID: 30650224 DOI: 10.1002/jms.4330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 12/19/2018] [Accepted: 01/08/2019] [Indexed: 06/09/2023]
Abstract
Hydralazine has been widely employed in the development of drugs, derivatization reagents, and ligands. In the present work, we reported a new type of dehydrogenated ion [M - H]+ that was produced from the hydralazine derivative of hexanal in electrospray ionization mass spectrometry (ESI-MS). The formation of [M - H]+ ions in the ESI-MS was found to be independent on the mobile phase composition of the liquid chromatography and ESI source parameters. A series of hydralazine derivatives of aldehyde were investigated to confirm this phenomenon. The results showed that hydralazine derivatives of aldehydes that contained an sp3 hybridization carbon with a hydrogen at the α-position of aldehydes could form the unexpected [M - H]+ ions, whereas hydralazine derivative of acetone could only generate [M + H]+ ion in the ESI-MS. We proposed the possible formation mechanism of [M - H]+ ion for the hydralazine derivatives of aldehydes: the [M - H]+ ion was possibly formed by the loss a hydrogen molecule (H2 ) from the protonated ion [M + H]+ . The results obtained from density functional theory (DFT) calculations supported this proposed formation mechanism of [M - H]+ ion.
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Affiliation(s)
- Hua-Ming Xiao
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, 430072, People's Republic of China
| | - Xian Wang
- Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Chemistry and Materials Science, South-Central University for Nationalities, Wuhan, Hubei, 430074, People's Republic of China
| | - Xing Yang
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, People's Republic of China
| | - Feng Zheng
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, 430072, People's Republic of China
| | - Yu-Qi Feng
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, 430072, People's Republic of China
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37
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Marlton SJP, McKinnon BI, Ucur B, Maccarone AT, Donald WA, Blanksby SJ, Trevitt AJ. Selecting and identifying gas-phase protonation isomers of nicotineH+ using combined laser, ion mobility and mass spectrometry techniques. Faraday Discuss 2019; 217:453-475. [DOI: 10.1039/c8fd00212f] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Protonation isomers of gas-phase nicotineH+ are separated and assigned using a combination of FAIMS and UV photodissociation action spectroscopy.
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Affiliation(s)
| | | | - Boris Ucur
- School of Chemistry
- University of Wollongong
- Wollongong
- Australia
| | | | | | - Stephen J. Blanksby
- Central Analytical Research Facility
- Institute for Future Environments
- Queensland University of Technology
- Brisbane
- Australia
| | - Adam J. Trevitt
- School of Chemistry
- University of Wollongong
- Wollongong
- Australia
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38
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Erabelli R, Xu S, Attygalle AB. Gas-phase protomers of p-(dimethylamino)chalcone investigated by travelling-wave ion mobility mass spectrometry (TWIMS). JOURNAL OF MASS SPECTROMETRY : JMS 2018; 53:954-962. [PMID: 29989269 DOI: 10.1002/jms.4265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 06/24/2018] [Accepted: 06/27/2018] [Indexed: 06/08/2023]
Abstract
Results from ion-mobility (IM) separation experiments demonstrate that O- and N-protomers of p-(dimethylamino)chalcone (p-DMAC) can coexist in the gas phase. The relative populations of the two protomers strongly depend on the ion-generating settings and the conditions the precursor ions experience from the point of their gas-phase inception to the time of their detection. Under relatively dry source conditions, the ratio of the gas-phase protomers generated under helium-plasma ionization (HePI) conditions is biased towards the thermodynamically favored O-protomer. However, when the humidity of the enclosed ion source was increased, the IM arrival-time distribution profile of the mass-selected protonated precursor of p-DMAC changed rapidly to one dominated by the N-protomer. Under spray-ionization conditions, the formation of the thermodynamically less favored protomer has been generally attributed to a phenomenon called kinetic trapping. Herein, we demonstrate that the population of thermodynamically less favored N-protomer can be dramatically increased simply by introducing water vapor to the HePI ion source.
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Affiliation(s)
- Ramu Erabelli
- Center for Mass Spectrometry, Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey
| | - Sihang Xu
- Center for Mass Spectrometry, Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey
| | - Athula B Attygalle
- Center for Mass Spectrometry, Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey
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39
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Bell MR, Cruzeiro VWD, Cismesia AP, Tesler LF, Roitberg AE, Polfer NC. Probing the Structures of Solvent-Complexed Ions Formed in Electrospray Ionization Using Cryogenic Infrared Photodissociation Spectroscopy. J Phys Chem A 2018; 122:7427-7436. [DOI: 10.1021/acs.jpca.8b05896] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Matthew R. Bell
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611-7200, United States
| | - Vinícius Wilian D. Cruzeiro
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611-7200, United States
| | - Adam P. Cismesia
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611-7200, United States
| | - Larry F. Tesler
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611-7200, United States
| | - Adrian E. Roitberg
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611-7200, United States
| | - Nicolas C. Polfer
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611-7200, United States
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40
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Xia H, Attygalle AB. Transformation of the gas-phase favored O-protomer of p-aminobenzoic acid to its unfavored N-protomer by ion activation in the presence of water vapor: An ion-mobility mass spectrometry study. JOURNAL OF MASS SPECTROMETRY : JMS 2018; 53:353-360. [PMID: 29377420 DOI: 10.1002/jms.4066] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/12/2018] [Accepted: 01/18/2018] [Indexed: 05/26/2023]
Abstract
An ion-mobility mass spectrometry study showed that the preferred O-protonated form of p-aminobenzoic in the gas phase can be converted to the thermodynamically less favored N-protomer by in-source collision-induced ion activation during the ion transfer process from the atmospheric region to the first vacuum region if the humidity is high in the ion source. Upon the addition of water vapor to the nitrogen gas used to promote the solid analyte to the gas phase under helium-plasma ionization conditions, the intensity of the ion-mobility arrival-time peak for the N-protomer increased dramatically. Evidently, the ion-activation process in the first vacuum region is able to provide the energy required to surmount the barrier to isomerize the O-protomer to the more energetic N-protomer. The transfer of the proton attached to the carbonyl oxygen atom of the O-protomer to the amino group takes place by a water-bridge mechanism. Apparently, the postionization transformations that take place during the transmission of ions from the atmospheric-pressure ion source to the detector, via different physical compartments of low to high vacuum, play an eminent role in determining the population ratios eventually manifested at the detector.
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Affiliation(s)
- Hanxue Xia
- Center for Mass Spectrometry, Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey, 07030, USA
| | - Athula B Attygalle
- Center for Mass Spectrometry, Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey, 07030, USA
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41
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Ieritano C, Featherstone J, Carr PJJ, Marta RA, Loire E, McMahon TB, Hopkins WS. The structures and properties of anionic tryptophan complexes. Phys Chem Chem Phys 2018; 20:26532-26541. [DOI: 10.1039/c8cp04533j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
IRMPD spectroscopy and electronic structure calculations are employed to identify π–π interactions in ionic tryptophan clusters.
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Affiliation(s)
| | | | | | - Rick A. Marta
- Department of Chemistry, University of Waterloo
- Waterloo
- Canada
| | - Estelle Loire
- Laboratoire Chimie Physique – CLIO, Bâtiment 201, Porte 2, Campus Universitaire d’Orsay
- France
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42
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Xia H, Attygalle AB. Untrapping Kinetically Trapped Ions: The Role of Water Vapor and Ion-Source Activation Conditions on the Gas-Phase Protomer Ratio of Benzocaine Revealed by Ion-Mobility Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:2580-2587. [PMID: 28936768 DOI: 10.1007/s13361-017-1806-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 08/25/2017] [Accepted: 08/30/2017] [Indexed: 06/07/2023]
Abstract
The role of water vapor in transforming the thermodynamically preferred species of protonated benzocaine to the less favored protomer was investigated using helium-plasma ionization (HePI) in conjunction with ion-mobility mass spectrometry (IM-MS). The IM arrival-time distribution (ATD) recorded from a neat benzocaine sample desorbed to the gas phase by a stream of dry nitrogen and ionized by HePI showed essentially one peak for the O-protonated species. However, when water vapor was introduced to the enclosed ion source, within a span of about 150 ms the ATD profile changed completely to one dominated by the N-protonated species. Under spray-based ionization conditions, the nature and composition of the solvents have been postulated to play a decisive role in defining the manifested protomer ratios. In reality, the solvent vapors present in the ion source (particularly the ambient humidity) indirectly dictate the gas-phase ratio of the protomers. Evidently, the gas-phase protomer ratio established at the confinement of the ions is readjusted by the ion-activation that takes place during the transmission of ions to the vacuum. Although it has been repeatedly stated that ions can retain a "memory" of their solution structures because they can be kinetically trapped, and thereby represent their solution-based stabilities, we show that the initial airborne ions can undergo significant transformations in the transit through the intermediate vacuum zones between the ion source and the mass detector. In this context, we demonstrate that the kinetically trapped N-protomer of benzocaine can be untrapped by reducing the humidity of the enclosed ion source. Graphical Abstract ᅟ.
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Affiliation(s)
- Hanxue Xia
- Center for Mass Spectrometry, Department of Biomedical Engineering, Chemistry, and Biological Sciences, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
| | - Athula B Attygalle
- Center for Mass Spectrometry, Department of Biomedical Engineering, Chemistry, and Biological Sciences, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
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43
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Cismesia AP, Tesler LF, Bell MR, Bailey LS, Polfer NC. Infrared ion spectroscopy inside a mass-selective cryogenic 2D linear ion trap. JOURNAL OF MASS SPECTROMETRY : JMS 2017; 52:720-727. [PMID: 28750482 PMCID: PMC5690808 DOI: 10.1002/jms.3975] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/18/2017] [Accepted: 07/20/2017] [Indexed: 06/07/2023]
Abstract
We demonstrate operation of the first cryogenic 2D linear ion trap (LIT) with mass-selective capabilities. This trap presents a number of advantages for infrared ion "action" spectroscopy studies, particularly those employing the "tagging/messenger" spectroscopy approach. The high trapping efficiencies, trapping capacities, and low detection limits make 2D LITs a highly suitable choice for low-concentration analytes from scarce biological samples. In our trap, ions can be cooled down to cryogenic temperatures to achieve higher-resolution infrared spectra, and individual ions can be mass selected prior to irradiation for a background-free photodissociation scheme. Conveniently, multiple tagged analyte ions can be mass isolated and efficiently irradiated in the same experiment, allowing their infrared spectra to be recorded in parallel. This multiplexed approach is critical in terms of increasing the duty cycle of infrared ion spectroscopy, which is currently a key weakness of the technique. The compact design of this instrument, coupled with powerful mass selection capabilities, set the stage for making cryogenic infrared ion spectroscopy viable as a bioanalytical tool in small molecule identification.
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Affiliation(s)
| | | | | | | | - Nicolas C. Polfer
- Correspondence to Nicolas C. Polfer, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL 32611-7200, USA.
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44
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FAIMS-MS-IR spectroscopy workflow: a multidimensional platform for the analysis of molecular isoforms. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/s12127-017-0225-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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45
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Bull JN, Coughlan NJA, Bieske EJ. Protomer-Specific Photochemistry Investigated Using Ion Mobility Mass Spectrometry. J Phys Chem A 2017; 121:6021-6027. [DOI: 10.1021/acs.jpca.7b05800] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- James N. Bull
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | | | - Evan J. Bieske
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
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46
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Chiavarino B, Crestoni ME, Fornarini S, Scuderi D, Salpin JY. Undervalued N3 Coordination Revealed in the Cisplatin Complex with 2'-Deoxyadenosine-5'-monophosphate by a Combined IRMPD and Theoretical Study. Inorg Chem 2017; 56:8793-8801. [PMID: 28718635 DOI: 10.1021/acs.inorgchem.7b00570] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The complex obtained by the reaction of cisplatin and 2'-deoxyadenosine-5'-monophosphate (5'-dAMP) in water has been isolated and detected by electrospray ionization mass spectrometry. The so-formed cis-[PtCl(NH3)2(5'-dAMP)]+ complex has been studied in detail by infrared multiple photon dissociation (IRMPD) spectroscopy in two spectral ranges, namely, 700-1900 and 2800-3800 cm-1, backed by quantum-chemical calculations at the B3LYP/LACV3P/6-311G** level of theory. In agreement with the computational results, the vibrational spectroscopic characterization of cis-[PtCl(NH3)2(5'-dAMP)]+ shows that the sampled ionic population comprises two major isomers, differentiated in the X-H stretching region by their distinct fragmentation patterns. One of these species presents coordination of the platinum moiety at the N3 position of adenine, whereas in the second one, platinum is bound at the N1 position of adenine. IRMPD kinetics have allowed an estimation of their relative proportions. Surprisingly, the most abundant component of cis-[PtCl(NH3)2(5'-dAMP)]+ is the N3 isomer, although it is slightly less stable than the other potential isomers in the gas phase. In contrast, the lowest-energy species, namely, the one showing cisplatin binding to the N7 position of adenine, seems to be the one less represented in the sampled ionic population. These findings suggest that the reaction of cisplatin with 5'-dAMP is governed by the kinetics of the process occurring in solution rather than by the thermodynamic factors.
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Affiliation(s)
- Barbara Chiavarino
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza" , Piazzale Aldo Moro 5, I-00185 Roma, Italy
| | - Maria Elisa Crestoni
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza" , Piazzale Aldo Moro 5, I-00185 Roma, Italy
| | - Simonetta Fornarini
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza" , Piazzale Aldo Moro 5, I-00185 Roma, Italy
| | - Debora Scuderi
- LCP, Université Paris Sud Orsay, CNRS, Université Paris-Saclay , F-91405 Orsay, France
| | - Jean-Yves Salpin
- LAMBE, Université d'Evry Val d'Essonne, CEA, CNRS, Université Paris-Saclay , F-91025 Evry, France.,LAMBE, Université Cergy-Pontoise, Université Paris-Seine , F-91025 Evry, France
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47
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Cismesia AP, Nicholls GR, Polfer NC. Amine vs. carboxylic acid protonation in ortho-, meta-, and para-aminobenzoic acid: An IRMPD spectroscopy study. JOURNAL OF MOLECULAR SPECTROSCOPY 2017; 332:79-85. [PMID: 28439142 PMCID: PMC5400370 DOI: 10.1016/j.jms.2016.10.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Infrared multiple photon dissociation (IRMPD) spectroscopy and computational chemistry are applied to the ortho-, meta-, and para- positional isomers of aminobenzoic acid to investigate whether the amine or the carboxylic acid are the favored sites of proton attachment in the gas phase. The NH and OH stretching modes yield distinct patterns that establish the carboxylic acid as the site of protonation in para-aminobenzoic acid, as opposed to the amine group in ortho- and meta-aminobenzoic acid, in agreement with computed thermochemistries. The trends for para- and meta-substitutions can be rationalized simplistically by inductive effects and resonant stabilization, and will be discussed in light of computed charge distributions based from electrostatic potentials. In ortho-aminobenzoic acid, the close proximity of the amine and acid groups allow a simultaneous interaction of the proton with both groups, thus stabilizing and delocalizing the charge more effectively, and compensating for some of the resonance stabilization effects.
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48
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Carita Correra T, Santos Fernandes A, Mota Reginato M, Colucci Ducati L, Berden G, Oomens J. Probing the geometry reorganization from solution to gas-phase in putrescine derivatives by IRMPD, 1H-NMR and theoretical calculations. Phys Chem Chem Phys 2017; 19:24330-24340. [DOI: 10.1039/c7cp04617k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Geometry reorganization of ESI formed ions are demonstrated and explicit calculations of the solution phase are shown to be relevant.
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Affiliation(s)
- Thiago Carita Correra
- Department of Fundamental Chemistry
- Institute of Chemistry
- University of São Paulo
- São Paulo
- Brazil
| | - André Santos Fernandes
- Department of Fundamental Chemistry
- Institute of Chemistry
- University of São Paulo
- São Paulo
- Brazil
| | - Marcelo Mota Reginato
- Department of Fundamental Chemistry
- Institute of Chemistry
- University of São Paulo
- São Paulo
- Brazil
| | - Lucas Colucci Ducati
- Department of Fundamental Chemistry
- Institute of Chemistry
- University of São Paulo
- São Paulo
- Brazil
| | - Giel Berden
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
| | - Jos Oomens
- Radboud University
- Institute for Molecules and Materials
- FELIX Laboratory
- 6525 ED Nijmegen
- The Netherlands
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