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Valadbeigi Y, Mirzahosseini F, Ilbeigi V, Matejcik S. Using dopants in the atmospheric pressure chemical ionization ion source to determine the site of protonation by ion mobility spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2024; 38:e9858. [PMID: 39005212 DOI: 10.1002/rcm.9858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 06/08/2024] [Accepted: 06/09/2024] [Indexed: 07/16/2024]
Abstract
RATIONALE Compounds like caffeine metabolites with more than one proton acceptor site can produce a mixture of isomeric protonated ions (protomers) in electrospray ionization and atmospheric pressure chemical ionization (APCI) ion sources. Discrimination between the protomers is of interest as the charge location influences ion structure and chemical and physical properties. METHODS Protonation of caffeine in an APCI ion source was studied using ion mobility spectrometry. The hydronium ions, H3O+(H2O)n, are the main reactant ions in the APCI ion source. Different dopant gases including NO2, NH3, and CH3NH2 were used to produce new reactant ions NO+, NH4 +, and CH3NH3 +, respectively. Density functional theory was employed to explain the experimental results and calculate the energies of the ionization reactions. RESULTS The ion mobility spectrum of caffeine showed three peaks. In the presence of NO2 dopant and NO+ reactant ion, caffeine was ionized via charge transfer and formation of M+ ion. As NH3 and CH3NH2 are stronger bases than H2O, the reactant ions NH4 + and CH3NH3 + selectively protonated the more basic site of caffeine, that is, the imidazole nitrogen. Using these dopants, we could attribute the first ion mobility peak to M+ ion, the second peak to the protonation of caffeine at the carbonyl oxygen atom, and the third peak to the protonation of the imidazole nitrogen atom. The calculated collisional cross-sections of M+ and the protomers of caffeine confirmed the peaks' assignment. CONCLUSIONS The criterion for the selection of an appropriate dopant is that its proton affinity (PA) should be between those of the proton acceptor sites of the molecule studied.
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Affiliation(s)
- Younes Valadbeigi
- Department of Chemistry, Faculty of Science, Imam Khomeini International University, Qazvin, Iran
| | - Fatemeh Mirzahosseini
- Department of Chemistry, Faculty of Science, Imam Khomeini International University, Qazvin, Iran
| | - Vahideh Ilbeigi
- Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia
| | - Stefan Matejcik
- Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia
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2
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Valadbeigi Y, Causon T. Computational and Experimental IM-MS Determination of the Protonated Structures of Antimalarial Drugs. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:1930-1939. [PMID: 39041666 PMCID: PMC11311536 DOI: 10.1021/jasms.4c00207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 07/11/2024] [Accepted: 07/15/2024] [Indexed: 07/24/2024]
Abstract
A combination of ion mobility-mass spectrometry (IM-MS) measurements and computational methods were used to study structural and physicochemical properties of a range of quinoline-based drugs: amodiaquine (AQ), cinchonine (CIN), chloroquine (CQ), mefloquine (MQ), pamaquine (PQ), primaquine (PR), quinacrine (QR), quinine (QN), and sitamaquine (SQ). In experimental studies, ionization of these compounds using atmospheric pressure chemical ionization (APCI) yields monoprotonated species in the gas phase while electrospray ionization (ESI) also produces diprotonated forms of AQ, CQ, and QR and also for PQ, SQ, and QN in the presence of formic acid as an additive. Comparison of the trajectory-method-calculated and experimental IM-derived collisional cross sections (CCSN2) were used to assign both the protonation sites and conformer geometry of all drugs considered with biases of 0.7-2.8% between calculated and experimental values. It was found that, in solution, AQ and QR are protonated at the ring nitrogen of the quinoline group, whereas the other drugs are protonated at the amine group of the alkyl chain. Finally, the conformers of [M + H]+ and [M + 2H]2+ assigned according to the lowest energies and CCSN2 calculations were used to calculate the pKa values of the antimalarial drugs and the relative abundance of these ions at different pH values that provided validation of the computational and experimental IM-MS results.
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Affiliation(s)
- Younes Valadbeigi
- Department
of Chemistry, Faculty of Science, Imam Khomeini
International University, Qazvin 34148-96818, Iran
| | - Tim Causon
- BOKU
University, Department of Chemistry, Institute
of Analytical Chemistry, Muthgasse 18, Vienna 1190, Austria
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3
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Johnson CR, Sabatini HM, Aderorho R, Chouinard CD. Dependency of fentanyl analogue protomer ratios on solvent conditions as measured by ion mobility-mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2024; 59:e5070. [PMID: 38989742 DOI: 10.1002/jms.5070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 06/13/2024] [Accepted: 06/18/2024] [Indexed: 07/12/2024]
Abstract
Recently, our group has shown that fentanyl and many of its analogues form prototropic isomers ("protomers") during electrospray ionization. These different protomers can be resolved using ion mobility spectrometry and annotated using mobility-aligned tandem mass spectrometry fragmentation. However, their formation and the extent to which experimental variables contribute to their relative ratio remain poorly understood. In the present study, we systematically investigated the effects of mixtures of common chromatographic solvents (water, methanol, and acetonitrile) and pH on the ratio of previously observed protomers for 23 fentanyl analogues. Interestingly, these ratios (N-piperidine protonation vs. secondary amine/O = protonation) decreased significantly for many analogues (e.g., despropionyl ortho-, meta-, and para-methyl fentanyl), increased significantly for others (e.g., cis-isofentanyl), and remained relatively constant for the others as solvent conditions changed from 100% organic solvent (methanol or acetonitrile) to 100% water. Interestingly, pH also had significant effects on this ratio, causing the change in ratio to switch in many cases. Lastly, increasing conditions to pH ≥ 4.0 also prompted the appearance of new mobility peaks for ortho- and para-methyl acetyl fentanyl, where all previous studies had only showed one single distribution. Because these ratios have promise to be used qualitatively for identification of these (and emerging) fentanyl analogues, understanding how various conditions (i.e., mobile phase selection and/or chromatographic gradient) affect their ratios is critically important to the development of advanced ion mobility and mass spectrometry methodologies to identify fentanyl analogues.
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Affiliation(s)
| | - Heidi M Sabatini
- Department of Chemistry, Clemson University, Clemson, SC, USA, 29634
| | - Ralph Aderorho
- Department of Chemistry, Clemson University, Clemson, SC, USA, 29634
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4
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Schäfer A, Debnath S, Tränkle J, Mohr T, Kappes MM. Acriflavine Is More than It Seems: Resolving Optical Properties of Multiple Isomeric Constituents at 5 K. J Phys Chem Lett 2024; 15:7295-7301. [PMID: 38980149 DOI: 10.1021/acs.jpclett.4c01517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Ion mobility spectrometry at room temperature was combined with vibrationally resolved electronic spectroscopy of mass-selected ions at 5 K to study the well-known cationic fluorophore acriflavine. One- and two-color photodepletion action spectra recorded in gas-phase (by helium tagging) as well as dispersed fluorescence spectra obtained in neon matrix (after soft-landing deposition) indicate that the primary cation mass electrosprayed from solution comprises two isomers with different optical properties. Theory at the TD-DFT level allowed full spectral assignment. The results have implications for the preparation of novel thin film photonic materials by low-energy ion beam deposition.
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Affiliation(s)
- Alexander Schäfer
- Institute of Physical Chemistry II, Karlsruhe Institute of Technology, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany
| | - Sreekanta Debnath
- Institute of Physical Chemistry II, Karlsruhe Institute of Technology, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany
| | - Jana Tränkle
- Institute of Physical Chemistry II, Karlsruhe Institute of Technology, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany
| | - Theresa Mohr
- Institute of Physical Chemistry II, Karlsruhe Institute of Technology, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany
| | - Manfred M Kappes
- Institute of Physical Chemistry II, Karlsruhe Institute of Technology, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
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5
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Hollerbach AL, Lin VS, Ibrahim YM, Ewing RG, Metz TO, Rodda KE. Elucidating the Gas-Phase Behavior of Nitazene Analog Protomers Using Structures for Lossless Ion Manipulations Ion Mobility-Orbitrap Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:1609-1621. [PMID: 38907730 DOI: 10.1021/jasms.4c00200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/24/2024]
Abstract
2-Benzylbenzimidazoles, or "nitazenes", are a class of novel synthetic opioids (NSOs) that are increasingly being detected alongside fentanyl analogs and other opioids in drug overdose cases. Nitazenes can be 20× more potent than fentanyl but are not routinely tested for during postmortem or clinical toxicology drug screens; thus, their prevalence in drug overdose cases may be under-reported. Traditional analytical workflows utilizing liquid chromatography-tandem mass spectrometry (LC-MS/MS) often require additional confirmation with authentic reference standards to identify a novel nitazene. However, additional analytical measurements with ion mobility spectrometry (IMS) may provide a path toward reference-free identification, which would greatly accelerate NSO identification rates in toxicology laboratories. Presented here are the first IMS and collision cross section (CCS) measurements on a set of fourteen nitazene analogs using a structures for lossless ion manipulations (SLIM)-orbitrap MS. All nitazenes exhibited two high intensity baseline-separated IMS distributions, which fentanyls and other drug and druglike compounds also exhibit. Incorporating water into the electrospray ionization (ESI) solution caused the intensities of the higher mobility IMS distributions to increase and the intensities of the lower mobility IMS distributions to decrease. Nitazenes lacking a nitro group at the R1 position exhibited the greatest shifts in signal intensities due to water. Furthermore, IMS-MS/MS experiments showed that the higher mobility IMS distributions of all nitazenes possessing a triethylamine group produced fragment ions with m/z 72, 100, and other low intensity fragments while the lower mobility IMS distributions only produced fragment ions with m/z 72 and 100. The IMS, solvent, and fragmentation studies provide experimental evidence that nitazenes potentially exhibit three gas-phase protomers. The cyclic IMS capability of SLIM was also employed to partially resolve four sets of structurally similar nitazene isomers (e.g., protonitazene/isotonitazene, butonitazene/isobutonitazene/secbutonitazene), showcasing the potential of using high-resolution IMS separations in MS-based workflows for reference-free identification of emerging nitazenes and other NSOs.
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Affiliation(s)
- Adam L Hollerbach
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Vivian S Lin
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Yehia M Ibrahim
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Robert G Ewing
- Nuclear, Chemistry & Biology Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Thomas O Metz
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Kabrena E Rodda
- Nuclear, Chemistry & Biology Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
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6
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Fan S, Lu H, Li C, Cai M, Shi J. Study on the Mass Spectrometry Cleavage Pattern of Quinolone Antibiotics. ChemistryOpen 2024:e202400061. [PMID: 38884376 DOI: 10.1002/open.202400061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/24/2024] [Indexed: 06/18/2024] Open
Abstract
RATIONALE Quinolone antibiotics are extensively used clinically for human treatment and in agriculture. However, improper and excessive use can lead to the persistence of quinolone residues in animal tissues, potentially accumulating in the human body and posing health risks. Investigating the correlation between mass spectrometry cleavage patterns and molecular structural features enhances the analytical framework for detecting trace or unknown impurities in quinolones. METHODS To collect data, we employed triple quadrupole linear ion trap mass spectrometry in electrospray positive ion mode. Primary mass spectrometry scanning was utilized to confirm parent ions, while secondary mass spectrometry scanning enabled the observation of fragment ions. The cleavage characteristics and pathways of the compounds were inferred from accurate mass-to-charge ratios obtained from both primary and secondary mass spectrometry. RESULTS Under soft ionization conditions, the compounds generally exhibited characteristic fragment ions of [M+H-H2O]+, [M+H-CO]+, and [M+H-H2O-CO]+. Additionally, subtle variations were observed in each compound due to differences in modifying groups. For instance, upon deacidification, the piperazine ring structure underwent breakage and rearrangement, yielding fragment ion peaks devoid of neutral molecules such as C2H5N, C3H7N, or C4H8N. Notably, compounds featuring a cyclopropyl substituent group at the N-1 position typically exhibited characteristic fragments resulting from the loss of the cyclopropyl radical (⋅C3H5). Moreover, substituents at the N-1 and C-8 positions, when linked to form a six-membered carbocyclic ring, were prone to cleavage, releasing the neutral C3H6 molecule. CONCLUSION Quinolone antibiotics share structural similarities in their parent nuclei, leading to partially similar cleavage pathways. Nevertheless, distinct cleavage patterns emerge due to variations in functional groups. According to the difference of mass spectrometry cleavage patterns, it can provide an identification basis for the measured detection of antibiotics.
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Affiliation(s)
- Susu Fan
- Nantong University, Seyuan road No.9, Nantong, Jiangsu, China E-mail address
| | - Hui Lu
- Qidong Secondary School of Jiangsu Province, Qixiu road No.536, Qidong, Nantong, Jiangsu, China
| | - Chunjian Li
- Nantong University, Seyuan road No.9, Nantong, Jiangsu, China E-mail address
| | - Meng Cai
- Nantong University, Seyuan road No.9, Nantong, Jiangsu, China E-mail address
| | - Jian Shi
- Nantong University, Seyuan road No.9, Nantong, Jiangsu, China E-mail address
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7
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Kumar M, Attygalle AB. Manipulating Non-Dissociative Transformations of Gaseous Ion Ensembles Prior to Ion-Mobility Separation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:1197-1207. [PMID: 38718179 DOI: 10.1021/jasms.4c00032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
Molecules with multiple sites capable of accepting protons form ensembles of protomers. The manifested protomer ratios in such ensembles are influenced by many experimental conditions. In a Synapt G2 ion mobility (IM)-enabled mass spectrometry system, there are several physical locations where ion population changes can be manifested. Using APCI-generated protomers of aminonaphthalenes, we investigated its intramolecular proton transfers from the N-protomer to the C-protomer. This lossless transformation of the N-protomer to the thermodynamically favored C-protomer can take place in the ion source itself. Initially, we learned that the cone gas slows down the transformation to the C-protomer. Gaseous ions are then accelerated in the first vacuum region, where ions undergo collisional activation (heating), which facilitates the transformation to the C-protomer. Afterward, the ions are mass selected and transferred to the pre-IM (Trap)-collision cell, where ions can also be transformed to the thermodynamically favored protomers. Trap accumulated ions are then released to the IM separator via a helium-filled entry cell. The role of helium is to minimize ion activation and scattering taking place upon entry to the high-pressure T-Wave IM separator (TWIMS). The helium cell is known to increase the IM peak resolution. However, we found that significant changes occur depending on the presence or absence of helium. Without helium, source-generated protomers rapidly changed to a predominantly thermodynamically favorable ensemble protomers. Apparently, the introduction of helium into the precell induced a dramatic decrease in collisional "heating" effect, which effectively slowed down the conversion rate of the amino-protomer into the more favorable ring-protomer. The final message is that mobilograms should not be considered as direct real-time, or intrinsic, representations of the protomer ratios in the ion source.
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Affiliation(s)
- Meenu Kumar
- 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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8
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Gutiérrez-Quintanilla A, Moge B, Compagnon I, Noble JA. Vibrational and electronic spectra of protonated vanillin: exploring protonation sites and isomerisation. Phys Chem Chem Phys 2024; 26:15358-15368. [PMID: 38767194 DOI: 10.1039/d3cp05573f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Photofragmentation spectra of protonated vanillin produced under electrospray ionisation (ESI) conditions have been recorded in the 3000-3700 cm-1 (vibrational) and 225-460 nm (electronic) ranges, using room temperature IRMPD (infrared multiphoton dissociation) and cryogenic UVPD (ultraviolet photodissociation) spectroscopies, respectively. The cold (∼50 K) electronic UVPD spectrum exhibits very well resolved vibrational structure for the S1 ← S0 and S3 ← S0 transitions, suggesting long excited state dynamics, similar to its simplest analogue, protonated benzaldehyde. The experimental data were combined with theoretical calculations to determine the protonation site and configurational isomer observed in the experiments.
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Affiliation(s)
- Alejandro Gutiérrez-Quintanilla
- CNRS, Aix Marseille Univ., PIIM, Physique des Interactions Ioniques et Moléculaires, UMR 7345, 13397 Marseille, France.
- Université de Pau et des Pays de l'Adour, E2S UPPA, CNRS, IPREM, Pau, France
| | - Baptiste Moge
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
| | - Isabelle Compagnon
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
| | - Jennifer A Noble
- CNRS, Aix Marseille Univ., PIIM, Physique des Interactions Ioniques et Moléculaires, UMR 7345, 13397 Marseille, France.
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9
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Benzenberg LR, Katzberger P, Wu R, Metternich JB, Riniker S, Zenobi R. Probing the Stability of a β-Hairpin Scaffold after Desolvation. J Phys Chem Lett 2024; 15:5041-5046. [PMID: 38700091 DOI: 10.1021/acs.jpclett.4c00920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
Probing the structural characteristics of biomolecular ions in the gas phase following native mass spectrometry (nMS) is of great interest, because noncovalent interactions, and thus native fold features, are believed to be largely retained upon desolvation. However, the conformation usually depends heavily on the charge state of the species investigated. In this study, we combine transition metal ion Förster resonance energy transfer (tmFRET) and ion mobility-mass spectrometry (IM-MS) with molecular dynamics (MD) simulations to interrogate the β-hairpin structure of GB1p in vacuo. Fluorescence lifetime values and collisional cross sections suggest an unfolding of the β-hairpin motif for higher charge states. MD simulations are consistent with experimental constraints, yet intriguingly provide an alternative structural interpretation: preservation of the β-hairpin is not only predicted for 2+ but also for 4+ charged species, which is unexpected given the substantial Coulomb repulsion for small secondary structure scaffolds.
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Affiliation(s)
- Lukas R Benzenberg
- Laboratory of Organic Chemistry, Department of Chemistry and Applied Biosciences ETH Zurich, Vladimir-Prelog-Weg 3, CH-8093 Zurich, Switzerland
| | - Paul Katzberger
- Institute of Molecular Physical Science, Department of Chemistry and Applied Biosciences ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Ri Wu
- Laboratory of Organic Chemistry, Department of Chemistry and Applied Biosciences ETH Zurich, Vladimir-Prelog-Weg 3, CH-8093 Zurich, Switzerland
| | - Jonas B Metternich
- Laboratory of Organic Chemistry, Department of Chemistry and Applied Biosciences ETH Zurich, Vladimir-Prelog-Weg 3, CH-8093 Zurich, Switzerland
| | - Sereina Riniker
- Institute of Molecular Physical Science, Department of Chemistry and Applied Biosciences ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Renato Zenobi
- Laboratory of Organic Chemistry, Department of Chemistry and Applied Biosciences ETH Zurich, Vladimir-Prelog-Weg 3, CH-8093 Zurich, Switzerland
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10
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Zimnicka MM. Structural studies of supramolecular complexes and assemblies by ion mobility mass spectrometry. MASS SPECTROMETRY REVIEWS 2024; 43:526-559. [PMID: 37260128 DOI: 10.1002/mas.21851] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 04/26/2023] [Accepted: 05/10/2023] [Indexed: 06/02/2023]
Abstract
Recent advances in instrumentation and development of computational strategies for ion mobility mass spectrometry (IM-MS) studies have contributed to an extensive growth in the application of this analytical technique to comprehensive structural description of supramolecular systems. Apart from the benefits of IM-MS for interrogation of intrinsic properties of noncovalent aggregates in the experimental gas-phase environment, its merits for the description of native structural aspects, under the premises of having maintained the noncovalent interactions innate upon the ionization process, have attracted even more attention and gained increasing interest in the scientific community. Thus, various types of supramolecular complexes and assemblies relevant for biological, medical, material, and environmental sciences have been characterized so far by IM-MS supported by computational chemistry. This review covers the state-of-the-art in this field and discusses experimental methods and accompanying computational approaches for assessing the reliable three-dimensional structural elucidation of supramolecular complexes and assemblies by IM-MS.
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Affiliation(s)
- Magdalena M Zimnicka
- Mass Spectrometry Group, Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw, Poland
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11
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Hollerbach AL, Ibrahim YM, Lin VS, Schultz KJ, Huntley AP, Armentrout PB, Metz TO, Ewing RG. Identification of Unique Fragmentation Patterns of Fentanyl Analog Protomers Using Structures for Lossless Ion Manipulations Ion Mobility-Orbitrap Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:793-803. [PMID: 38469802 DOI: 10.1021/jasms.4c00049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
The opioid crisis in the United States is being fueled by the rapid emergence of new fentanyl analogs and precursors that can elude traditional library-based screening methods, which require data from known reference compounds. Since reference compounds are unavailable for new fentanyl analogs, we examined if fentanyls (fentanyl + fentanyl analogs) could be identified in a reference-free manner using a combination of electrospray ionization (ESI), high-resolution ion mobility (IM) spectrometry, high-resolution mass spectrometry (MS), and higher-energy collision-induced dissociation (MS/MS). We analyzed a mixture containing nine fentanyls and W-15 (a structurally similar molecule) and found that the protonated forms of all fentanyls exhibited two baseline-separated IM distributions that produced different MS/MS patterns. Upon fragmentation, both IM distributions of all fentanyls produced two high intensity fragments, resulting from amine site cleavages. The higher mobility distributions of all fentanyls also produced several low intensity fragments, but surprisingly, these same fragments exhibited much greater intensities in the lower mobility distributions. This observation demonstrates that many fragments of fentanyls predominantly originate from one of two different gas-phase structures (suggestive of protomers). Furthermore, increasing the water concentration in the ESI solution increased the intensity of the lower mobility distribution relative to the higher mobility distribution, which further supports that fentanyls exist as two gas-phase protomers. Our observations on the IM and MS/MS properties of fentanyls can be exploited to positively differentiate fentanyls from other compounds without requiring reference libraries and will hopefully assist first responders and law enforcement in combating new and emerging fentanyls.
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Affiliation(s)
- Adam L Hollerbach
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Yehia M Ibrahim
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Vivian S Lin
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Katherine J Schultz
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Adam P Huntley
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - P B Armentrout
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Thomas O Metz
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Robert G Ewing
- Nuclear, Chemistry & Biology Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
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12
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Zhang B, Burchill L, Altalhi WAO, Ma HZ, O'Hair RAJ. A fixed-charge model of the N-protomer of 4-aminobenzoic acid to facilitate the study of the unimolecular and bimolecular chemistry of its "neutral" carboxylic acid group. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2024; 38:e9681. [PMID: 38355884 DOI: 10.1002/rcm.9681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/24/2023] [Accepted: 11/25/2023] [Indexed: 02/16/2024]
Abstract
RATIONALE There are a growing number of examples of protomers formed via electrospray ionization (ESI) that do not fragment under mobile proton conditions, giving rise to distinct tandem mass spectra. To model the N-protomer of 4-aminobenzoic acid, here we study the gas-phase unimolecular and bimolecular chemistry of the 4-(carboxyphenyl)trimethylammonium ion. METHODS 4-(Carboxyphenyl)trimethylammonium iodide was synthesized, purified via recrystallization and transferred to the gas phase via ESI. 4-(Carboxyphenyl)trimethylammonium ion, 7, was mass selected and subjected to collision-induced dissociation and ion-molecule reactions in a linear ion trap mass spectrometer. RESULTS The major fragmentation channel for the fixed-charge cation 7 is methyl radical loss, whereas loss of trimethylamine and CO2 represents minor pathways. The free carboxylic acid functional group of 7 is unreactive toward a number of neutral reagents (methanol, acetone, acetonitrile, and N,N'-diisopropylcarbodiimide). 7 reacts very slowly with trimethylborate via addition-elimination, consistent with density functional theory (DFT) calculations that show this reaction is slightly endothermic. The deuterated cation 7(D) undergoes slow D/H exchange with ethanol, and DFT calculations reveal that a flip-flop mechanism operates. CONCLUSIONS The free carboxylic group of 7 is not very reactive toward neutral reagents in the gas phase.
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Affiliation(s)
- Beiang Zhang
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Laura Burchill
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Weam A O Altalhi
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- Department of Chemistry, Prince Sattam Bin Abdulaziz University, Hotat Bani Tamim, Saudi Arabia
| | - Howard Z Ma
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Richard A J O'Hair
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
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Hirata K, Akasaka K, Dopfer O, Ishiuchi SI, Fujii M. Transition from vehicle to Grotthuss proton transfer in a nanosized flask: cryogenic ion spectroscopy of protonated p-aminobenzoic acid solvated with D 2O. Chem Sci 2024; 15:2725-2730. [PMID: 38404372 PMCID: PMC10882521 DOI: 10.1039/d3sc05455a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/18/2024] [Indexed: 02/27/2024] Open
Abstract
Proton transfer (PT) is one of the most ubiquitous reactions in chemistry and life science. The unique nature of PT has been rationalized not by the transport of a solvated proton (vehicle mechanism) but by the Grotthuss mechanism in which a proton is transported to the nearest proton acceptor along a hydrogen-bonded network. However, clear experimental evidence of the Grotthuss mechanism has not been reported yet. Herein we show by infrared spectroscopy that a vehicle-type PT occurs in the penta- and hexahydrated clusters of protonated p-aminobenzoic acid, while Grotthuss-type PT is observed in heptahydrated clusters, indicating a change in the PT mechanism depending on the degree of hydration. These findings emphasize the importance of the usually ignored vehicle mechanism as well as the degree of hydration. It highlights the possibility of controlling the PT mechanism by the number of water molecules in chemical and biological environments.
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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
- International Research Frontiers Initiative, Tokyo Institute of Technology 4259 Nagatsuta-cho, Midori-ku Yokohama 226-8503 Japan
| | - 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
| | - 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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14
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Chung NA, May JC, Robinson RAS, McLean JA. Solvent Composition Can Have a Measurable Influence on the Ion Mobility-Derived Collision Cross Section of Small Molecules. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:234-243. [PMID: 38082535 DOI: 10.1021/jasms.3c00338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Ion mobility (IM) is an important analytical technique for increasing identification coverage of metabolites in untargeted studies, especially when integrated into traditional liquid chromatography-mass spectrometry workflows. While there has been extensive work surrounding best practices to obtain and standardize collision cross section (CCS) measurements necessary for comparing across different IM techniques and laboratories, there has been little investigation into experimental factors beyond the mobility separation region that could potentially influence CCS measurements. The first-principles derived CCS of 15 chemical standards were evaluated across 27 aqueous:organic solvent compositions using a high-precision drift tube instrument. A small but measurable dependency of the CCS on the solvent composition was observed, with the larger analytes from this study (m/z > 400) exhibiting a characteristic increase in CCS at the intermediate (40-60%) solvent compositions. Parallels to the behavior of solvent viscosity and protonation site tautomers (protomers) were noted, although the origin of these solvent-dependent CCS trends is as yet unclear. Taken together, these findings document a solvent dependency on CCS, which, while minor (<0.5%), identifies an important need for reporting the solvent system when utilizing CCS in comparative ion mobility studies.
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Affiliation(s)
- Nadjali A Chung
- Center for Innovative Technology, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Jody C May
- Center for Innovative Technology, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Renã A S Robinson
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - John A McLean
- Center for Innovative Technology, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, United States
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15
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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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16
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Lee J, Kim H, Lee H, Boraste DR, Kim K, Seo J. Protomer of Imipramine Captured in Cucurbit[7]uril. J Phys Chem A 2023; 127:10758-10765. [PMID: 38091518 DOI: 10.1021/acs.jpca.3c04556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Small molecules possessing multiple proton-accessible sites are important not only to many biological systems but also to host-guest chemistry; their protonation states are causal to boosting or hindering specific host-guest interactions. However, determining the protonation site is not trivial. Herein, we conduct electrospray ionization ion mobility spectrometry-mass spectrometry to imipramine, a known molecule with two protonation sites, based on the introduction of cucurbit[7]uril as a host molecule. For protonated imipramine, the proposed strategy allows clear distinction of the two protomers as host-guest complex ions and can be leveraged to capture the energetically less preferable protomer of the protonated imipramine.
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Affiliation(s)
- Jiyeon Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Hyerim Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Hochan Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
- Center for Self-assembly and Complexity, Institute for Basic Science, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Deepak R Boraste
- Center for Self-assembly and Complexity, Institute for Basic Science, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Kimoon Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
- Center for Self-assembly and Complexity, Institute for Basic Science, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Jongcheol Seo
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
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17
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Limbach MN, Do TD. Solvent-Free Nuclear Magnetic Resonance Spectroscopy of Charged Molecules. J Phys Chem A 2023; 127:9149-9157. [PMID: 37861438 DOI: 10.1021/acs.jpca.3c05241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy of small molecules protonated in a solvent-free environment was successfully demonstrated. The method is referred to as solvent-free protonation NMR (SoF-NMR). Leveraging matrix-assisted ionization (MAI), we generated protonated species of aniline, 4-chloroaniline, 4-aminobiphenyl, and benzocaine for NMR analysis under mild pressure and temperature conditions. The SoF-NMR spectra were compared to traditional solution NMR spectra, and the shift changes in nuclear spin resonance frequencies verify that these small molecules are protonated by 3-nitrobenzonitrile (3-NBN). As the sample pressure decreased, new spectral features appeared, indicating the presence of differently charged species. Several advantages of SoF-NMR are highlighted, such as the elimination of H/D exchange in labile protons, resulting in the precise observation of protons that are otherwise transient in solution. Notably, the data on benzocaine show evidence of neutral, N-protonated, and O-protonated species all in the same spectrum. SoF-NMR eliminates the solvent effects and interactions that can hinder important spectral features. Optimizing SoF-NMR will result in more cost-effective and efficient NMR experimentation to monitor high-temperature, solvent-free reactions. SoF-NMR has a viable future application for studying exchangeable protons, intermediates, and products in gas-phase chemistry.
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Affiliation(s)
- Miranda N Limbach
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Thanh D Do
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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18
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Houthuijs KJ, Horn M, Vughs D, Martens J, Brunner AM, Oomens J, Berden G. Identification of organic micro-pollutants in surface water using MS-based infrared ion spectroscopy. CHEMOSPHERE 2023; 341:140046. [PMID: 37660788 DOI: 10.1016/j.chemosphere.2023.140046] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/29/2023] [Accepted: 08/31/2023] [Indexed: 09/05/2023]
Abstract
Comprehensive monitoring of organic micro-pollutants (OMPs) in drinking water sources relies on non-target screening (NTS) using liquid-chromatography and high-resolution mass spectrometry (LC-HRMS). Identification of OMPs is typically based on accurate mass and tandem mass spectrometry (MS/MS) data by matching against entries in compound databases and MS/MS spectral libraries. MS/MS spectra are, however, not always diagnostic for the full molecular structure and, moreover, emerging OMPs or OMP transformation products may not be present in libraries. Here we demonstrate how infrared ion spectroscopy (IRIS), an emerging MS-based method for structural elucidation, can aid in the identification of OMPs. IRIS measures the IR spectrum of an m/z-isolated ion in a mass spectrometer, providing an orthogonal diagnostic for molecular identification. Here, we demonstrate the workflow for identification of OMPs in river water and show how quantum-chemically predicted IR spectra can be used to screen potential candidates and suggest structural assignments. A crucial step herein is to define a set of candidate structures, presumably including the actual OMP, for which we present several strategies based on domain knowledge, the IR spectrum and MS/MS spectrum.
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Affiliation(s)
- Kas J Houthuijs
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED, Nijmegen, the Netherlands
| | - Marijke Horn
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED, Nijmegen, the Netherlands
| | - Dennis Vughs
- KWR Water Research Institute, Chemical Water Quality and Health, P.O. Box 1072, 3430 BB, Nieuwegein, the Netherlands
| | - Jonathan Martens
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED, Nijmegen, the Netherlands
| | - Andrea M Brunner
- KWR Water Research Institute, Chemical Water Quality and Health, P.O. Box 1072, 3430 BB, Nieuwegein, the Netherlands; TNO, Environmental Modelling, Sensing and Analysis (EMSA), Princetonlaan 8, 3584 CB, Utrecht, the Netherlands
| | - Jos Oomens
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED, Nijmegen, the Netherlands; van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands
| | - Giel Berden
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED, Nijmegen, the Netherlands.
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19
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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: 0] [Impact Index Per Article: 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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20
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Valadbeigi Y, Causon T. Mechanism of formation and ion mobility separation of protomers and deprotomers of diaminobenzoic acids and aminophthalic acids. Phys Chem Chem Phys 2023. [PMID: 37490344 DOI: 10.1039/d3cp01968c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
Aminobenzoic acids are well-established candidates for understanding the formation of isomeric ions in positive mode electrospray ionization as they yield both N- and O-protomers (prototropic isomers) at the amine and carbonyl sites, respectively. In the present work, a combination of ion mobility-mass spectrometry and density functional theory calculations to determine the protonation and deprotonation behaviour of four diamino benzoic acid and four aminophthalic acid isomers is presented. The additional COOH group on the ring of aminophthalic acids provides experimental evidence regarding the mechanism of intramolecular NH3+ → O proton transfer, which has been the subject of debate in recent years. To determine the proton acceptor O atom, ion mobility spectra of the fragments of protomers were used as a new method for the confidential assignment of the O-protomer structure, confirming only short-distance intramolecular NH3+ → O proton transfer. Additionally, the substitution pattern both influences the basicity of the protonation sites and enables these molecules to form internal hydrogen bonds with the protonated or deprotonated sites. The formation of the hydrogen bonds in the deprotonated aminophthalic acids changed the charge distribution and subsequently their ion mobility-derived collision cross sections in nitrogen (CCSN2) leading to separation of the four isomers studied. Finally, an interesting effect of the substitution pattern was observed as a synergistic electron-donating effect of the amine groups of 3,5-diaminobenzoic acid on enhancing the basicity of the carbon atom C2 of the ring and previously unreported formation of a C-protomer within aminobenzoic acid systems.
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Affiliation(s)
- Younes Valadbeigi
- Department of Chemistry, Faculty of Science, Imam Khomeini International University, Qazvin, Iran.
| | - Tim Causon
- University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Analytical Chemistry, Muthgasse 18, 1190 Vienna, Austria.
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21
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Ashworth EK, Dezalay J, Ryan CRM, Ieritano C, Hopkins WS, Chambrier I, Cammidge AN, Stockett MH, Noble JA, Bull JN. Protomers of the green and cyan fluorescent protein chromophores investigated using action spectroscopy. Phys Chem Chem Phys 2023. [PMID: 37465988 DOI: 10.1039/d3cp02661b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
The photophysics of biochromophore ions often depends on the isomeric or protomeric distribution, yet this distribution, and the individual isomer contributions to an action spectrum, can be difficult to quantify. Here, we use two separate photodissociation action spectroscopy instruments to record electronic spectra for protonated forms of the green (pHBDI+) and cyan (Cyan+) fluorescent protein chromophores. One instrument allows for cryogenic (T = 40 ± 10 K) cooling of the ions, while the other offers the ability to perform protomer-selective photodissociation spectroscopy. We show that both chromophores are generated as two protomers when using electrospray ionisation, and that the protomers have partially overlapping absorption profiles associated with the S1 ← S0 transition. The action spectra for both species span the 340-460 nm range, although the spectral onset for the pHBDI+ protomer with the proton residing on the carbonyl oxygen is red-shifted by ≈40 nm relative to the lower-energy imine protomer. Similarly, the imine and carbonyl protomers are the lowest energy forms of Cyan+, with the main band for the carbonyl protomer red-shifted by ≈60 nm relative to the lower-energy imine protomer. The present strategy for investigating protomers can be applied to a wide range of other biochromophore ions.
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Affiliation(s)
- Eleanor K Ashworth
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Jordan Dezalay
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | | | - Christian Ieritano
- Department of Chemistry, University of Waterloo, Waterloo N2L 3G1, Canada
| | - W Scott Hopkins
- Department of Chemistry, University of Waterloo, Waterloo N2L 3G1, Canada
| | - Isabelle Chambrier
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Andrew N Cammidge
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Mark H Stockett
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | | | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
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22
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Majeed HA, Bos TS, Voeten RLC, Kranenburg RF, van Asten AC, Somsen GW, Kohler I. Trapped ion mobility mass spectrometry of new psychoactive substances: Isomer-specific identification of ring-substituted cathinones. Anal Chim Acta 2023; 1264:341276. [PMID: 37230720 DOI: 10.1016/j.aca.2023.341276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/18/2023] [Accepted: 04/23/2023] [Indexed: 05/27/2023]
Abstract
New psychoactive substances (NPS) are synthetic derivatives of illicit drugs designed to mimic their psychoactive effects. NPS are typically not controlled under drug acts or their legal status depends on their molecular structure. Discriminating isomeric forms of NPS is therefore crucial for forensic laboratories. In this study, a trapped ion mobility spectrometry time-of-flight mass spectrometry (TIMS-TOFMS) approach was developed for the identification of ring-positional isomers of synthetic cathinones, a class of compounds representing two-third of all NPS seized in Europe in 2020. The optimized workflow features narrow ion-trapping regions, mobility calibration by internal reference, and a dedicated data-analysis tool, allowing for accurate relative ion-mobility assessment and high-confidence isomer identification. Ortho-, meta- and para-isomers of methylmethcathinone (MMC) and bicyclic ring isomers of methylone were assigned based on their specific ion mobilities within 5 min, including sample preparation and data analysis. The resolution of two distinct protomers per cathinone isomer added to the confidence in identification. The developed approach was successfully applied to the unambiguous assignment of MMC isomers in confiscated street samples. These findings demonstrate the potential of TIMS-TOFMS for forensic case work requiring fast and highly-confident assignment cathinone-drug isomers in confiscated samples.
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Affiliation(s)
- Hany A Majeed
- Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, Amsterdam, the Netherlands
| | - Tijmen S Bos
- Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, Amsterdam, the Netherlands
| | - Robert L C Voeten
- Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, Amsterdam, the Netherlands
| | - Ruben F Kranenburg
- Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, Amsterdam, the Netherlands; 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
- Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, Amsterdam, the Netherlands; 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
| | - Govert W Somsen
- Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, Amsterdam, the Netherlands
| | - Isabelle Kohler
- Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, 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.
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23
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Lin C, Zhou X, Zhang H, Fu Z, Yang H, Zhang M, Hu P. Deciphering and investigating fragment mechanism of quinolones using multi-collision energy mass spectrometry and computational chemistry strategy. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37:e9514. [PMID: 37012644 DOI: 10.1002/rcm.9514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 03/28/2023] [Accepted: 03/29/2023] [Indexed: 05/17/2023]
Abstract
RATIONALE Quinolones show characteristic fragments in mass spectrometry (MS) analysis due to their common core structures, and energy-dependent differences among these fragments are generated through the same fragmentation pathway of different molecules. Computational chemistry, which provides quantitative results of molecule parameters, is helpful for investigating the mechanisms of chemistry. METHODS MS/MS spectra of five quinolones, namely norfloxacin (NOR), enoxacin (ENO), enrofloxacin (ENR), gatifloxacin (GAT), and lomefloxacin (LOM), were acquired for deciphering fragmentation pathways under multi-collision energy (CE). Computational methods were used for excluding little possibility pathways from the point of view of energy and stable conformations, whereas optimized collision energy (OCE) and maximum relative intensity (MRI) of major competitive fragments were investigated and confirmed using computational results. RESULTS Fragmentation results of NOR, ENO, ENR, and GAT were deciphered using experimental and computational data, of which fragmentation regularities were summarized. Fragmentation pathways of LOM were deciphered under the guidance of foregoing regularities. Meanwhile, the whole process was validated by comparing OCE and MRI and computational energy results, which showed good agreement. CONCLUSIONS A strategy for explaining quinolone fragmentation results of multi-CE values and deciphering fragment mechanism using computational methods was developed. Relevant data and strategy may provide ideas for how to design and decipher new drug molecules with similar structures.
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Affiliation(s)
- Chuhui Lin
- Shanghai Key Laboratory of Functional Materials Chemistry, Department of Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Meilong road No.130, Shanghai, China
| | - Xudong Zhou
- Shanghai Key Laboratory of Functional Materials Chemistry, Department of Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Meilong road No.130, Shanghai, China
| | - Hongyang Zhang
- Shanghai Key Laboratory of Functional Materials Chemistry, Department of Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Meilong road No.130, Shanghai, China
| | - Zhibo Fu
- Shanghai Key Laboratory of Functional Materials Chemistry, Department of Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Meilong road No.130, Shanghai, China
| | - Haoyu Yang
- Shanghai Key Laboratory of Functional Materials Chemistry, Department of Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Meilong road No.130, Shanghai, China
| | - Min Zhang
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Department of pharmaceutical engineering, School of Pharmacy, East China University of Science and Technology, Meilong road No.130, Shanghai, China
| | - Ping Hu
- Shanghai Key Laboratory of Functional Materials Chemistry, Department of Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Meilong road No.130, Shanghai, China
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24
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Houthuijs KJ, Berden G, Engelke UFH, Gautam V, Wishart DS, Wevers RA, Martens J, Oomens J. An In Silico Infrared Spectral Library of Molecular Ions for Metabolite Identification. Anal Chem 2023. [PMID: 37262385 DOI: 10.1021/acs.analchem.3c01078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Infrared ion spectroscopy (IRIS) continues to see increasing use as an analytical tool for small-molecule identification in conjunction with mass spectrometry (MS). The IR spectrum of an m/z selected population of ions constitutes a unique fingerprint that is specific to the molecular structure. However, direct translation of an IR spectrum to a molecular structure remains challenging, as reference libraries of IR spectra of molecular ions largely do not exist. Quantum-chemically computed spectra can reliably be used as reference, but the challenge of selecting the candidate structures remains. Here, we introduce an in silico library of vibrational spectra of common MS adducts of over 4500 compounds found in the human metabolome database. In total, the library currently contains more than 75,000 spectra computed at the DFT level that can be queried with an experimental IR spectrum. Moreover, we introduce a database of 189 experimental IRIS spectra, which is employed to validate the automated spectral matching routines. This demonstrates that 75% of the metabolites in the experimental data set are correctly identified, based solely on their exact m/z and IRIS spectrum. Additionally, we demonstrate an approach for specifically identifying substructures by performing a search without m/z constraints to find structural analogues. Such an unsupervised search paves the way toward the de novo identification of unknowns that are absent in spectral libraries. We apply the in silico spectral library to identify an unknown in a plasma sample as 3-hydroxyhexanoic acid, highlighting the potential of the method.
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Affiliation(s)
- Kas J Houthuijs
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Nijmegen 6525 ED, The Netherlands
| | - Giel Berden
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Nijmegen 6525 ED, The Netherlands
| | - Udo F H Engelke
- Department of Genetics, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen 6525 GA, The Netherlands
| | - Vasuk Gautam
- Department of Biological Sciences, University of Alberta, Edmonton AB T6G 2E9, Canada
| | - David S Wishart
- Department of Biological Sciences, University of Alberta, Edmonton AB T6G 2E9, Canada
- Department of Computing Science, University of Alberta, Edmonton, AB T6G 2E8, Canada
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB T6G 2B7, Canada
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Ron A Wevers
- Department of Genetics, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen 6525 GA, The Netherlands
| | - Jonathan Martens
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Nijmegen 6525 ED, The Netherlands
| | - Jos Oomens
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Nijmegen 6525 ED, The Netherlands
- van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam 1098 XH, The Netherlands
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25
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Christofi E, Barran P. Ion Mobility Mass Spectrometry (IM-MS) for Structural Biology: Insights Gained by Measuring Mass, Charge, and Collision Cross Section. Chem Rev 2023; 123:2902-2949. [PMID: 36827511 PMCID: PMC10037255 DOI: 10.1021/acs.chemrev.2c00600] [Citation(s) in RCA: 43] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Indexed: 02/26/2023]
Abstract
The investigation of macromolecular biomolecules with ion mobility mass spectrometry (IM-MS) techniques has provided substantial insights into the field of structural biology over the past two decades. An IM-MS workflow applied to a given target analyte provides mass, charge, and conformation, and all three of these can be used to discern structural information. While mass and charge are determined in mass spectrometry (MS), it is the addition of ion mobility that enables the separation of isomeric and isobaric ions and the direct elucidation of conformation, which has reaped huge benefits for structural biology. In this review, where we focus on the analysis of proteins and their complexes, we outline the typical features of an IM-MS experiment from the preparation of samples, the creation of ions, and their separation in different mobility and mass spectrometers. We describe the interpretation of ion mobility data in terms of protein conformation and how the data can be compared with data from other sources with the use of computational tools. The benefit of coupling mobility analysis to activation via collisions with gas or surfaces or photons photoactivation is detailed with reference to recent examples. And finally, we focus on insights afforded by IM-MS experiments when applied to the study of conformationally dynamic and intrinsically disordered proteins.
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Affiliation(s)
- Emilia Christofi
- Michael Barber Centre for Collaborative
Mass Spectrometry, Manchester Institute of Biotechnology, University of Manchester, Princess Street, Manchester M1 7DN, United Kingdom
| | - Perdita Barran
- Michael Barber Centre for Collaborative
Mass Spectrometry, Manchester Institute of Biotechnology, University of Manchester, Princess Street, Manchester M1 7DN, United Kingdom
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26
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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: 0] [Impact Index Per Article: 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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27
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Valadbeigi Y, Causon T. Monitoring intramolecular proton transfer with ion mobility-mass spectrometry and in-source ion activation. Chem Commun (Camb) 2023; 59:1673-1676. [PMID: 36689277 DOI: 10.1039/d2cc05237g] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Here, we show how intramolecular proton transfer can be induced and monitored with the example of polycyclic aromatic amines using in-source ion-activation and ion mobility-mass spectrometry. Experiment and DFT calculations reveal that the protonation rate of C-atoms in aromatic rings is controlled by the energy barrier of intramolecular NH3+ → C proton transfer.
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Affiliation(s)
- Younes Valadbeigi
- University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Analytical Chemistry, Muthgasse 18, 1190 Vienna, Austria.
| | - Tim Causon
- University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Analytical Chemistry, Muthgasse 18, 1190 Vienna, Austria.
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28
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Fu D, Habtegabir SG, Wang H, Feng S, Han Y. Understanding of protomers/deprotomers by combining mass spectrometry and computation. Anal Bioanal Chem 2023:10.1007/s00216-023-04574-1. [PMID: 36737499 DOI: 10.1007/s00216-023-04574-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 01/19/2023] [Accepted: 01/27/2023] [Indexed: 02/05/2023]
Abstract
Multifunctional compounds may form different prototropic isomers under different conditions, which are known as protomers/deprotomers. In biological systems, these protomer/deprotomer isomers affect the interaction modes and conformational landscape between compounds and enzymes and thus present different biological activities. Study on protomers/deprotomers is essentially the study on the acidity/basicity of each intramolecular functional group and its effect on molecular structure. In recent years, the combination of mass spectrometry (MS) and computational chemistry has been proven to be a powerful and effective means to study prototropic isomers. MS-based technologies are developed to discriminate and characterize protomers/deprotomers to provide structural information and monitor transformations, showing great superiority than other experimental methods. Computational chemistry is used to predict the thermodynamic stability of protomers/deprotomers, provide the simulated MS/MS spectra, infrared spectra, and calculate collision cross-section values. By comparing the theoretical data with the corresponding experimental results, the researchers can not only determine the protomer/deprotomer structure, but also investigate the structure-activity relationship in a given system. This review covers various MS methods and theoretical calculations and their devotion to isomer discrimination, structure identification, conformational transformation, and phase transition investigation of protomers/deprotomers.
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Affiliation(s)
- Dali Fu
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, People's Republic of China
| | - Sara Girmay Habtegabir
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, People's Republic of China
| | - Haodong Wang
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, People's Republic of China
| | - Shijie Feng
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, People's Republic of China
| | - Yehua Han
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, People's Republic of China.
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29
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Elmotasem H, El-Marasy SA, Mohamed AL. Benzocaine mesoporous silica nanoparticles/bio polysaccharides-based hydrogels loaded cotton bandage as a platform for topical anesthesia. RESULTS IN CHEMISTRY 2023. [DOI: 10.1016/j.rechem.2023.100830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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30
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Samarasinghe I, Attygalle AB. Impact of Ambient Vapors on Spectra of 4-Nitroaniline Recorded under Atmospheric Solids Analysis Probe (ASAP) Mass Spectrometric Conditions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:205-217. [PMID: 36689202 DOI: 10.1021/jasms.2c00259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Thermally desorbed 4-nitroaniline (4-NA), upon atmospheric pressure chemical ionization (APCI), generates gaseous ions for its protonated species. The APCI mass spectrum recorded under mild in-source ion-activating conditions from 4-NA showed a peak at m/z 139, whereas that acquired under high ion-activating conditions showed two additional peaks at m/z 122 (•OH loss) and 92 (•NO loss). The spectrum changed instantaneously when acetonitrile vapor was introduced to the source. In the new spectrum, both m/z 122 and 92 peaks were absent, while a new peak appeared at m/z 93. Ion-mobility separation carried out with the m/z 139 ion revealed that the initial ion represented the thermodynamically favored nitro-protonated tautomer. The ion population changed to an ensemble dominated by the less-favored amino-protomer when acetonitrile vapor was introduced to the ion source. The amino-protomer, upon collisional activation, loses •NO2 to generate an m/z 93 ion, which was confirmed to be the 4-dehydroanilinium ion. Ion mobility provided a practical way to monitor the changes secured by acetonitrile vapor because the two protomers showed different arrival times. Under spray-ionization conditions, the formation of the thermodynamically less favored protomer has been attributed to kinetic trapping. Our study demonstrated that the less favored amino-protomer could be generated by introducing acetonitrile vapor under nonspray conditions. Apparently, under APCI conditions, protonated water vapor attaches to the nitro group to generate a proton-bound heterodimer, which upon activation dissociates to yield the nitro-protomer. In contrast, protonated acetonitrile makes a tighter complex preferentially with the amino group, which upon activation breaks to the amino-protomer.
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Affiliation(s)
- Ishira Samarasinghe
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey07030, United States
| | - Athula B Attygalle
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey07030, United States
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31
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Paglia G, Smith AJ, Astarita G. Ion mobility mass spectrometry in the omics era: Challenges and opportunities for metabolomics and lipidomics. MASS SPECTROMETRY REVIEWS 2022; 41:722-765. [PMID: 33522625 DOI: 10.1002/mas.21686] [Citation(s) in RCA: 90] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 01/17/2021] [Accepted: 01/17/2021] [Indexed: 06/12/2023]
Abstract
Researchers worldwide are taking advantage of novel, commercially available, technologies, such as ion mobility mass spectrometry (IM-MS), for metabolomics and lipidomics applications in a variety of fields including life, biomedical, and food sciences. IM-MS provides three main technical advantages over traditional LC-MS workflows. Firstly, in addition to mass, IM-MS allows collision cross-section values to be measured for metabolites and lipids, a physicochemical identifier related to the chemical shape of an analyte that increases the confidence of identification. Second, IM-MS increases peak capacity and the signal-to-noise, improving fingerprinting as well as quantification, and better defining the spatial localization of metabolites and lipids in biological and food samples. Third, IM-MS can be coupled with various fragmentation modes, adding new tools to improve structural characterization and molecular annotation. Here, we review the state-of-the-art in IM-MS technologies and approaches utilized to support metabolomics and lipidomics applications and we assess the challenges and opportunities in this growing field.
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Affiliation(s)
- Giuseppe Paglia
- School of Medicine and Surgery, University of Milano-Bicocca, Vedano al Lambro (MB), Italy
| | - Andrew J Smith
- School of Medicine and Surgery, University of Milano-Bicocca, Vedano al Lambro (MB), Italy
| | - Giuseppe Astarita
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, District of Columbia, USA
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32
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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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33
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Braak FT, Elferink H, Houthuijs KJ, Oomens J, Martens J, Boltje TJ. Characterization of Elusive Reaction Intermediates Using Infrared Ion Spectroscopy: Application to the Experimental Characterization of Glycosyl Cations. Acc Chem Res 2022; 55:1669-1679. [PMID: 35616920 PMCID: PMC9219114 DOI: 10.1021/acs.accounts.2c00040] [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: 12/30/2022]
Abstract
![]()
A detailed
understanding of the reaction mechanism(s) leading to
stereoselective product formation is crucial to understanding and
predicting product formation and driving the development of new synthetic
methodology. One way to improve our understanding of reaction mechanisms
is to characterize the reaction intermediates involved in product
formation. Because these intermediates are reactive, they are often
unstable and therefore difficult to characterize using experimental
techniques. For example, glycosylation reactions are critical steps
in the chemical synthesis of oligosaccharides and need to be stereoselective
to provide the desired α- or β-diastereomer. It remains
challenging to predict and control the stereochemical outcome of glycosylation
reactions, and their reaction mechanisms remain a hotly debated topic.
In most cases, glycosylation reactions take place via reaction mechanisms
in the continuum between SN1- and SN2-like pathways.
SN2-like pathways proceeding via the displacement of a
contact ion pair are relatively well understood because the reaction
intermediates involved can be characterized by low-temperature NMR
spectroscopy. In contrast, the SN1-like pathways proceeding
via the solvent-separated ion pair, also known as the glycosyl cation,
are poorly understood. SN1-like pathways are more challenging
to investigate because the glycosyl cation intermediates involved
are highly reactive. The highly reactive nature of glycosyl cations
complicates their characterization because they have a short lifetime
and rapidly equilibrate with the corresponding contact ion pair. To
overcome this hurdle and enable the study of glycosyl cation stability
and structure, they can be generated in a mass spectrometer in the
absence of a solvent and counterion in the gas phase. The ease of
formation, stability, and fragmentation of glycosyl cations have been
studied using mass spectrometry (MS). However, MS alone provides little
information about the structure of glycosyl cations. By combining
mass spectrometry (MS) with infrared ion spectroscopy (IRIS), the
determination of the gas-phase structures of glycosyl cations has
been achieved. IRIS enables the recording of gas-phase infrared spectra
of glycosyl cations, which can be assigned by matching to reference
spectra predicted from quantum chemically calculated vibrational spectra.
Here, we review the experimental setups that enable IRIS of glycosyl
cations and discuss the various glycosyl cations that have been characterized
to date. The structure of glycosyl cations depends on the relative
configuration and structure of the monosaccharide substituents, which
can influence the structure through both steric and electronic effects.
The scope and relevance of gas-phase glycosyl cation structures in
relation to their corresponding condensed-phase structures are also
discussed. We expect that the workflow reviewed here to study glycosyl
cation structure and reactivity can be extended to many other reaction
types involving difficult-to-characterize ionic intermediates.
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Affiliation(s)
- Floor ter Braak
- Radboud University, Institute for Molecules and Materials, Synthetic Organic Chemistry, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Hidde Elferink
- Radboud University, Institute for Molecules and Materials, Synthetic Organic Chemistry, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Kas J. Houthuijs
- Radboud University, FELIX Laboratory, Institute of Molecules and Materials, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Jos Oomens
- Radboud University, FELIX Laboratory, Institute of Molecules and Materials, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Jonathan Martens
- Radboud University, FELIX Laboratory, Institute of Molecules and Materials, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Thomas J. Boltje
- Radboud University, Institute for Molecules and Materials, Synthetic Organic Chemistry, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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34
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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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35
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McCann A, Kune C, Massonnet P, Far J, Ongena M, Eppe G, Quinton L, De Pauw E. Cyclic Peptide Protomer Detection in the Gas Phase: Impact on CCS Measurement and Fragmentation Patterns. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:851-858. [PMID: 35467879 DOI: 10.1021/jasms.2c00035] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
With the recent improvements in ion mobility resolution, it is now possible to separate small protomeric tautomers, called protomers. In larger molecules above 1000 Da such as peptides, a few studies suggest that protomers do exist as well and may contribute to their gas-phase conformational heterogeneity. In this work, we observed a CCS distribution that can be explained by the presence of protomers of surfactin, a small lipopeptide with no basic site. Following preliminary density functional theoretical calculations, several protonation sites in the gas phase were energetically favorable in positive ionization mode. Experimentally, at least three near-resolved IM peaks were observed in positive ionization mode, while only one was detected in negative ionization mode. These results were in good agreement with the DFT predictions. CID breakdown curve analysis after IM separation showed different inflection points (CE50) suggesting that different intramolecular interactions were implied in the stabilization of the structures of surfactin. The fragment ratio observed after collision-induced fragmentation was also different, suggesting different ring-opening localizations. All these observations support the presence of protomers on the cyclic peptide moieties of the surfactin. These data strongly suggest that protomeric tautomerism can still be observed on molecules above 1000 Da if the IM resolving power is sufficient. It also supports that the proton localization involves a change in the 3D structure that can affect the experimental CCS and the fragmentation channels of such peptides.
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Affiliation(s)
- Andréa McCann
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liège, 4000 Liège, Belgium
| | - Christopher Kune
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liège, 4000 Liège, Belgium
| | - Philippe Massonnet
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liège, 4000 Liège, Belgium
- Maastricht Multimodal Molecular Imaging (M4I) Institute, Division of Imaging Mass Spectrometry, 6229ER Maastricht, Limburg, The Netherlands
| | - Johann Far
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liège, 4000 Liège, Belgium
| | - Marc Ongena
- Gembloux Agro-Bio Tech, University of Liege, 5030 Gembloux, Belgium
| | - Gauthier Eppe
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liège, 4000 Liège, Belgium
| | - Loïc Quinton
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liège, 4000 Liège, Belgium
| | - Edwin De Pauw
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liège, 4000 Liège, Belgium
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36
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Schäfer A, Vetsova VA, Schneider EK, Kappes M, Seitz M, Daumann LJ, Weis P. Ion Mobility Studies of Pyrroloquinoline Quinone Aza-Crown Ether-Lanthanide Complexes. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:722-730. [PMID: 35300493 DOI: 10.1021/jasms.2c00023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Lanthanide-dependent enzymes and their biomimetic complexes have arisen as an interesting target of research in the past decade. These enzymes, specifically, pyrroloquinoline quinone (PQQ)-bearing methanol dehydrogenases, efficiently convert alcohols to the respective aldehydes. To rationally design bioinspired alcohol dehydrogenation catalysts, it is imperative to understand the species involved in catalysis. However, given the extremely flexible coordination sphere of lanthanides, it is often difficult to assess the number and nature of the active species. Here, we show how such questions can be addressed by using a combination of ion mobility spectrometry, mass spectrometry, and quantum-chemical calculations to study the test systems PQQ and lanthanide-PQQ-crown ether ligand complexes. Specifically, we determine the gas-phase structures of [PQQH2]-, [PQQH2+H2O]-, [PQQH2+MeOH]-, [PQQ-15c5+H]+, and [PQQ-15c5+Ln+NO3]2+ (Ln = La to Lu, except Pm). In the latter case, a trend to smaller collision cross sections across the lanthanide series is clearly observable, in line with the well-known lanthanide contraction. We hope that in the future such investigations will help to guide the design and understanding of lanthanide-based biomimetic complexes optimized for catalytic function.
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Affiliation(s)
- Alexander Schäfer
- Karlsruhe Institute of Technology Institute of Physical Chemistry Fritz-Haber-Weg 2, 76128 Karlsruhe, Germany
| | - Violeta A Vetsova
- Department of Chemistry Ludwig Maximilian University of Munich Butenandtstraße 5-13, 81377 Munich, Germany
| | - Erik K Schneider
- Karlsruhe Institute of Technology Institute of Physical Chemistry Fritz-Haber-Weg 2, 76128 Karlsruhe, Germany
| | - Manfred Kappes
- Karlsruhe Institute of Technology Institute of Physical Chemistry Fritz-Haber-Weg 2, 76128 Karlsruhe, Germany
- Karlsruhe Institute of Technology Institute of Nanotechnology Hermann von Helmholtz Pl 1,76344 Eggenstein Leopoldshafen, Germany
| | - Michael Seitz
- University of Tübingen Institute of Inorganic Chemistry Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Lena J Daumann
- Department of Chemistry Ludwig Maximilian University of Munich Butenandtstraße 5-13, 81377 Munich, Germany
| | - Patrick Weis
- Karlsruhe Institute of Technology Institute of Physical Chemistry Fritz-Haber-Weg 2, 76128 Karlsruhe, Germany
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37
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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: 9] [Impact Index Per Article: 4.5] [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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38
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Zhang L, Wang Y, Zheng F, Zhu D, Liang Y, Shi Q. Influence Exerted by the Solvent Effect on the Mobility Peak of 1,8-Naphthalic Anhydride in Ion Mobility Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:457-462. [PMID: 35089717 DOI: 10.1021/jasms.1c00299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The collision cross-section (CCS) values of ions determined by ion mobility-mass spectrometry (IM-MS) can be used to deduce the shape and size of the ions. For each compound, as well as its isomer or tautomer, a unique arrival time peak was obtained in extracted ion mobility (EIM) spectra, which corresponded to a specific CCS value. However, the generation of solvated ions by electrospray ionization (ESI) increases the number of mobility peaks, which makes the EIM spectra difficult to interpret. In this study, solvent clusters formed by acetonitrile and methanol around 1,8-naphthalic anhydride (1,8-NA) cations ([C12H6O3 + H]+1,8-NA) were investigated using trapped ion mobility spectrometry-time-of-flight mass spectrometry (TIMS-TOF MS). The effects of infusion flow rate, nebulizer gas pressure, drying gas rate, and drying gas temperature on the formation of solvent clusters from acetonitrile and methanolic solution were systematically studied. The formation of solvent clusters was observed with infusion flow rates increased, which was manifested by the larger experimental CCS values of [C12H6O3 + H]+1,8-NA. Acetonitrile tended to form solvent clusters around ions more readily than methanol. These solvent clusters were stable enough to be detected by TIMS, but they cannot survive under ion activation conditions of mass spectrometry (MS). Increasing the nebulizer gas pressure seems to be a better way to eliminate the formation of solvent clusters in TIMS-TOF MS and give a "cleaner" EIM spectra. The current research demonstrates that more attention should be paid to the solvent effect on CCS values and their interpretation.
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Affiliation(s)
- Lingzhi Zhang
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, P.R. China
| | - Yinghao Wang
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, P.R. China
| | - Fang Zheng
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, P.R. China
| | - Di Zhu
- College of Science, China University of Petroleum, Beijing 102249, P.R. China
| | - Yongmei Liang
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, P.R. China
| | - Quan Shi
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, P.R. China
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39
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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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40
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Song XC, Dreolin N, Damiani T, Canellas E, Nerin C. Prediction of Collision Cross Section Values: Application to Non-Intentionally Added Substance Identification in Food Contact Materials. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:1272-1281. [PMID: 35041428 PMCID: PMC8815070 DOI: 10.1021/acs.jafc.1c06989] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/31/2021] [Accepted: 01/05/2022] [Indexed: 05/24/2023]
Abstract
The synthetic chemicals in food contact materials can migrate into food and endanger human health. In this study, the traveling wave collision cross section in nitrogen values of more than 400 chemicals in food contact materials were experimentally derived by traveling wave ion mobility spectrometry. A support vector machine-based collision cross section (CCS) prediction model was developed based on CCS values of food contact chemicals and a series of molecular descriptors. More than 92% of protonated and 81% of sodiated adducts showed a relative deviation below 5%. Median relative errors for protonated and sodiated molecules were 1.50 and 1.82%, respectively. The model was then applied to the structural annotation of oligomers migrating from polyamide adhesives. The identification confidence of 11 oligomers was improved by the direct comparison of the experimental data with the predicted CCS values. Finally, the challenges and opportunities of current machine-learning models on CCS prediction were also discussed.
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Affiliation(s)
- Xue-Chao Song
- Department
of Analytical Chemistry, Aragon Institute of Engineering Research
I3A, CPS-University of Zaragoza, Maria de Luna 3, 50018 Zaragoza, Spain
| | - Nicola Dreolin
- Waters
Corporation, Altrincham
Road, SK9 4AX Wilmslow, U.K.
| | - Tito Damiani
- Institute
of Organic Chemistry and Biochemistry, Flemingovo náměstí 542/2, 160 00 Prague, Czech Republic
| | - Elena Canellas
- Department
of Analytical Chemistry, Aragon Institute of Engineering Research
I3A, CPS-University of Zaragoza, Maria de Luna 3, 50018 Zaragoza, Spain
| | - Cristina Nerin
- Department
of Analytical Chemistry, Aragon Institute of Engineering Research
I3A, CPS-University of Zaragoza, Maria de Luna 3, 50018 Zaragoza, Spain
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41
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Kathan M, Crespi S, Thiel NO, Stares DL, Morsa D, de Boer J, Pacella G, van den Enk T, Kobauri P, Portale G, Schalley CA, Feringa BL. A light-fuelled nanoratchet shifts a coupled chemical equilibrium. NATURE NANOTECHNOLOGY 2022; 17:159-165. [PMID: 34916655 PMCID: PMC8956507 DOI: 10.1038/s41565-021-01021-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 09/29/2021] [Indexed: 05/23/2023]
Abstract
Biological molecular machines enable chemical transformations, assembly, replication and motility, but most distinctively drive chemical systems out of-equilibrium to sustain life1,2. In such processes, nanometre-sized machines produce molecular energy carriers by driving endergonic equilibrium reactions. However, transforming the work performed by artificial nanomachines3-5 into chemical energy remains highly challenging. Here, we report a light-fuelled small-molecule ratchet capable of driving a coupled chemical equilibrium energetically uphill. By bridging two imine6-9 macrocycles with a molecular motor10,11, the machine forms crossings and consequently adopts several distinct topologies by either a thermal (temporary bond-dissociation) or photochemical (unidirectional rotation) pathway. While the former will relax the machine towards the global energetic minimum, the latter increases the number of crossings in the system above the equilibrium value. Our approach provides a blueprint for coupling continuous mechanical motion performed by a molecular machine with a chemical transformation to reach an out-of-equilibrium state.
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Affiliation(s)
- Michael Kathan
- Stratingh Institute for Chemistry, Center for Systems Chemistry and Zernike Institute for Advanced Materials, Faculty of Mathematics and Natural Sciences, University of Groningen, Groningen, the Netherlands.
| | - Stefano Crespi
- Stratingh Institute for Chemistry, Center for Systems Chemistry and Zernike Institute for Advanced Materials, Faculty of Mathematics and Natural Sciences, University of Groningen, Groningen, the Netherlands
| | - Niklas O Thiel
- Stratingh Institute for Chemistry, Center for Systems Chemistry and Zernike Institute for Advanced Materials, Faculty of Mathematics and Natural Sciences, University of Groningen, Groningen, the Netherlands
| | - Daniel L Stares
- Institut für Chemie und Biochemie der Freien Universität Berlin, Berlin, Germany
| | - Denis Morsa
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
| | - John de Boer
- Stratingh Institute for Chemistry, Center for Systems Chemistry and Zernike Institute for Advanced Materials, Faculty of Mathematics and Natural Sciences, University of Groningen, Groningen, the Netherlands
| | - Gianni Pacella
- Macromolecular Chemistry and New Polymeric Materials and Zernike Institute for Advanced Materials, Faculty of Mathematics and Natural Sciences, University of Groningen, Groningen, the Netherlands
| | - Tobias van den Enk
- Stratingh Institute for Chemistry, Center for Systems Chemistry and Zernike Institute for Advanced Materials, Faculty of Mathematics and Natural Sciences, University of Groningen, Groningen, the Netherlands
| | - Piermichele Kobauri
- Stratingh Institute for Chemistry, Center for Systems Chemistry and Zernike Institute for Advanced Materials, Faculty of Mathematics and Natural Sciences, University of Groningen, Groningen, the Netherlands
| | - Giuseppe Portale
- Macromolecular Chemistry and New Polymeric Materials and Zernike Institute for Advanced Materials, Faculty of Mathematics and Natural Sciences, University of Groningen, Groningen, the Netherlands
| | - Christoph A Schalley
- Institut für Chemie und Biochemie der Freien Universität Berlin, Berlin, Germany.
| | - Ben L Feringa
- Stratingh Institute for Chemistry, Center for Systems Chemistry and Zernike Institute for Advanced Materials, Faculty of Mathematics and Natural Sciences, University of Groningen, Groningen, the Netherlands.
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42
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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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43
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Marlton SJP, Trevitt A. Laser Photodissocation, Action Spectroscopy and Mass Spectrometry Unite to Detect and Separate Isomers. Chem Commun (Camb) 2022; 58:9451-9467. [DOI: 10.1039/d2cc02101c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The separation and detection of isomers remains a challenge for many areas of mass spectrometry. This article highlights laser photodissociation and ion mobility strategies that have been deployed to tackle...
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44
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Johnson SI, Baer MD, Raugei S. Protonation of Serine in Gas and Condensed and Microsolvated States in Aqueous Solution. J Phys Chem A 2021; 126:44-52. [PMID: 34941278 DOI: 10.1021/acs.jpca.1c08795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Identification of molecules and elucidation of their chemical structure are ubiquitous problems in chemistry. Mass spectrometry (MS) can be used due to its sensitivity and versatility. For detection to occur, analytes must be ionized and transferred to the gas phase. Soft ionization processes such as electrospray ionization are popular; however, resulting microsolvated phases can alter the chemistry of analytes and therefore detection and identification. To understand these processes, we use computational methods to probe the ionization propensity of serine in the gas phase, aqueous microsolvated clusters, and aqueous solution. We show that the tautomeric form of serine is altered by the presence of water, as five water molecules can stabilize the zwitterionic tautomer. Inclusion of cosolutes such as ions can stabilize the zwitterion with as few as one or two water molecules present. We demonstrate that ionization propensity, as measured by gas phase bacisity, can increase by over 100 kJ/mol when placed in a small water-serine cluster, showing the sensitivity of the chemistry of microsolvated analytes. Finally, detailed analysis reveals that small droplets (less than seven water molecules) are extremely sensitive to addition of further water molecules. Beyond this limit, structural and electronic properties change little with droplet size.
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Affiliation(s)
- Samantha I Johnson
- Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Marcel D Baer
- Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Simone Raugei
- Pacific Northwest National Laboratory, Richland, Washington 99354, United States
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45
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Takeda N, Hirata K, Tsuruta K, Santis GD, Xantheas SS, Ishiuchi SI, Fujii M. Gas phase protonated nicotine is a mixture of pyridine- and pyrrolidine-protonated conformers: implications for its native structure in the nicotinic acetylcholine receptor. Phys Chem Chem Phys 2021; 24:5786-5793. [PMID: 34939632 DOI: 10.1039/d1cp05175j] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The infrared (IR) spectra of gas phase protonated nicotine has been measured in the never-before probed N-H "fingerprint region" (3200-3500 cm-1). The protonated molecules generated by an electrospray source are thermalized in the first ion trap with water vapor and He gas at a pre-determined temperature prior to being probed by IR spectroscopy in the second ion trap at 4 K. The IR spectra exhibit two N-H stretching bands which are assigned to the pyridine and pyrrolidine protomers with the aid of high-level electronic structure calculations. This finding is in sharp contrast to previous spectroscopic studies that suggested a single population of the pyridine protomer. The relative populations of the two protomers vary by changing the temperature of the thermalizing trap from 180-300 K. The relative conformer populations at 240 K and 300 K are well reproduced by the theoretical calculations, unequivocally determining that gas phase nicotine is a 3 : 2 mixture of both pyridine and pyrrolidine protomers at room temperature. The thermalizing anhydrous vapor does not result in any population change. It rather demonstrates the catalytic role of water in achieving equilibrium between the two protomers. The combination of IR spectroscopy and electronic structure calculations establish the small energy difference between the pyridine and pyrrolidine protomers in nicotine. One of the gas phase nicotine pyrrolidine protomers has the closest conformational resemblance among all low-lying energy isomers with the X-ray structure of nicotine in the nicotinic acetylcholine receptor (nAChR).
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Affiliation(s)
- Naoya Takeda
- 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 4259 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan. .,Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259, Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan.
| | - Kazuya Tsuruta
- 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
| | - Garrett D Santis
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Sotiris S Xantheas
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259, Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan. .,Department of Chemistry, University of Washington, Seattle, WA 98195, USA.,Advanced Computing, Mathematics and Data Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS K1-83, Richland, WA 99352, USA
| | - 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 4259 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan. .,Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, 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.,Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259, Nagatsuta-cho, Midori-ku, Yokohama, 226-8503, Japan.
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46
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van Outersterp RE, Martens J, Peremans A, Lamard L, Cuyckens F, Oomens J, Berden G. Evaluation of table-top lasers for routine infrared ion spectroscopy in the analytical laboratory. Analyst 2021; 146:7218-7229. [PMID: 34724520 PMCID: PMC8607882 DOI: 10.1039/d1an01406d] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 10/20/2021] [Indexed: 01/12/2023]
Abstract
Infrared ion spectroscopy is increasingly recognized as a method to identify mass spectrometry-detected analytes in many (bio)chemical areas and its integration in analytical laboratories is now on the horizon. Commercially available quadrupole ion trap mass spectrometers are attractive ion spectroscopy platforms but operate at relatively high pressures. This promotes collisional deactivation which directly interferes with the multiple-photon excitation process required for ion spectroscopy. To overcome this, infrared lasers having a high instantaneous power are required and therefore a majority of analytical studies have been performed at infrared free electron laser facilities. Proliferation of the technique to routine use in analytical laboratories requires table-top infrared lasers and optical parametric oscillators (OPOs) are the most suitable candidates, offering both relatively high intensities and reasonable spectral tuning ranges. Here, we explore the potential of a range of commercially available high-power OPOs for ion spectroscopy, comparing systems with repetition rates of 10 Hz, 20 kHz, 80 MHz and a continuous-wave (cw) system. We compare the performance for various molecular ions and show that the kHz and MHz repetition-rate systems outperform cw and 10 Hz systems in photodissociation efficiency and offer several advantages in terms of cost-effectiveness and practical implementation in an analytical laboratory not specialized in laser spectroscopy.
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Affiliation(s)
- Rianne E van Outersterp
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands.
| | - Jonathan Martens
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands.
| | - André Peremans
- Laboratoire Physique de la Matière et du Rayonnement (P.M.R), Université de Namur, 5000 Namur, Belgium
| | | | - Filip Cuyckens
- Drug Metabolism & Pharmacokinetics, Janssen R&D, Beerse, Belgium
| | - Jos Oomens
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, 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
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands.
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47
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Structural Diversity of Di-Metalized Arginine Evidenced by Infrared Multiple Photon Dissociation (IRMPD) Spectroscopy in the Gas Phase. Molecules 2021; 26:molecules26216546. [PMID: 34770955 PMCID: PMC8587954 DOI: 10.3390/molecules26216546] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/23/2021] [Accepted: 10/27/2021] [Indexed: 12/18/2022] Open
Abstract
Although metal cations are prevalent in biological media, the species of multi-metal cationized biomolecules have received little attention so far. Studying these complexes in isolated state is important, since it provides intrinsic information about the interaction among them on the molecular level. Our investigation here demonstrates the unexpected structural diversity of such species generated by a matrix-assisted laser desorption ionization (MALDI) source in the gas phase. The photodissociation spectroscopic and theoretical study reflects that the co-existing isomers of [Arg+Rb+K−H]+ can have energies ≥95 kJ/mol higher than that of the most stable one. While the result can be rationalized by the great isomerization energy barrier due to the coordination, it strongly reminds us to pay more attention to their structural diversities for multi-metalized fundamental biological molecules, especially for the ones with the ubiquitous alkali metal ions.
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48
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Szalwinski LJ, Hu Y, Morato NM, Cooks RG, Salentijn GI. Novel Ion Trap Scan Modes to Develop Criteria for On-Site Detection of Sulfonamide Antibiotics. Anal Chem 2021; 93:13904-13911. [PMID: 34617742 PMCID: PMC8529578 DOI: 10.1021/acs.analchem.1c02790] [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: 11/30/2022]
Abstract
![]()
Advances in ambient
ionization techniques have facilitated the
direct analysis of complex mixtures without sample preparation. Significant
attention has been given to innovating ionization methods so that
multiple options are now available, allowing for ready selection of
the best methods for particular analyte classes. These ambient techniques
are commonly implemented on benchtop systems, but their potential
application with miniature mass spectrometers for in situ measurements is even more powerful. These applications require that
attention be paid to tailoring the mass spectrometric methodology
for the on-site operation. In this study, combinations of scan modes
are employed to efficiently determine what tandem mass spectrometry
(MS/MS) operations are most useful for detecting sulfonamides using
a miniature ion trap after ionization. First, mixtures of representative
sulfonamide antibiotics were interrogated using a 2D MS/MS scan on
a benchtop ion trap in order to determine which class-specific fragments
(ionic or neutral) are shared between the sulfonamides and thus have
diagnostic value. Then, three less-used combination scans were recorded:
(i) a simultaneous precursor ion scan was used to detect both analytes
and an internal standard in a single ion injection event to optimize
quantitative performance; (ii) a simultaneous precursor/neutral loss
scan was used to improve detection limits; and finally, (iii) the
simultaneous precursor/neutral loss scan was implemented in a miniature
mass spectrometer and representative sulfonamides were detected at
concentrations as low as 100 ng/mL by nano-electrospray and 0.5 ng
absolute by paper spray ionization, although improvements in the stability
of the home-built instrumentation are needed to further optimize performance.
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Affiliation(s)
- Lucas J Szalwinski
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Yanyang Hu
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Nicolás M Morato
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - R Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Gert Ij Salentijn
- Laboratory of Organic Chemistry, Wageningen University, Wageningen 6708 WE, The Netherlands.,Wageningen Food Safety Research (WFSR), Wageningen University & Research, Wageningen 6700 AE, The Netherlands
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49
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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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50
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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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