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Articles 1 - 7 of 7
Full-Text Articles in Social and Behavioral Sciences
Rapid Profiling Of Laser-Induced Photochemistry In Single Microdroplets Using Mass Spectrometry, Phillip J. Tracey, Bartholomew S. Vaughn, Brendon J. Roberts, Berwyck L. J Poad, Adam J. Trevitt
Rapid Profiling Of Laser-Induced Photochemistry In Single Microdroplets Using Mass Spectrometry, Phillip J. Tracey, Bartholomew S. Vaughn, Brendon J. Roberts, Berwyck L. J Poad, Adam J. Trevitt
Adam Trevitt
Rapid assessment of laser-induced photochemistry in single microdroplets is afforded by on-demand microdroplet generation coupled to a commercial ion-trap mass spectrometer. Single microdroplets (diameter 50 μm, 65 pL) fall on a steel needle held at +2 kV where they subsequently form a spray that is directed toward the inlet of an ion-trap mass spectrometer. It is demonstrated that single microdroplet mass spectra are recordable, one at a time, for methanol droplets containing 100 μM 4-iodoaniline. Extending on this, to probe laser-initiated photochemistry in single picoliter volumes, a UV laser pulse is timed to intercept the droplet before hitting the needle. …
Product Branching Fractions Of The Ch + Propene Reaction From Synchrotron Photoionization Mass Spectrometry, Adam J. Trevitt, Matthew B. Prendergast, Fabien Goulay, John D. Savee, David L. Osborn, Craig A. Taatjes, Stephen R. Leone
Product Branching Fractions Of The Ch + Propene Reaction From Synchrotron Photoionization Mass Spectrometry, Adam J. Trevitt, Matthew B. Prendergast, Fabien Goulay, John D. Savee, David L. Osborn, Craig A. Taatjes, Stephen R. Leone
Adam Trevitt
The CH(X2Π) + propene reaction is studied in the gas phase at 298 K and 4 Torr (533.3 Pa) using VUV synchrotron photoionization mass spectrometry. The dominant product channel is the formation of C4H6 (m/z 54) + H. By fitting experimental photoionization spectra to measured spectra of known C4H6 isomers, the following relative branching fractions are obtained: 1,3-butadiene (0.63 ± 0.13), 1,2-butadiene (0.25 ± 0.05), and 1-butyne (0.12 ± 0.03) with no detectable contribution from 2-butyne. The CD + propene reaction is also studied and two product channels are observed that correspond to C4H6 (m/z 54) + D and C4H5D …
Photodissociation Of Tempo-Modified Peptides: New Approaches To Radical-Directed Dissociation Of Biomolecules, David L. Marshall, Christopher S. Hansen, Adam J. Trevitt, Han Bin Oh, Stephen J. Blanksby
Photodissociation Of Tempo-Modified Peptides: New Approaches To Radical-Directed Dissociation Of Biomolecules, David L. Marshall, Christopher S. Hansen, Adam J. Trevitt, Han Bin Oh, Stephen J. Blanksby
Adam Trevitt
Radical-directed dissociation of gas phase ions is emerging as a powerful and complementary alternative to traditional tandem mass spectrometric techniques for biomolecular structural analysis. Previous studies have identified that coupling of 2-[(2,2,6,6-tetramethylpiperidin-1-oxyl)methyl]benzoic acid (TEMPO-Bz) to the N-terminus of a peptide introduces a labile oxygen–carbon bond that can be selectively activated upon collisional activation to produce a radical ion. Here we demonstrate that structurally-defined peptide radical ions can also be generated upon UV laser photodissociation of the same TEMPO-Bz derivatives in a linear ion-trap mass spectrometer. When subjected to further mass spectrometric analyses, the radical ions formed by a single laser …
Observation Of Nondegenerate Cavity Modes For A Distorted Cavity Modes For A Distorted Polystyrene Microsphere, Adam J. Trevitt, Philip J. Wearne, Evan J. Bieske, Michael D. Schuder
Observation Of Nondegenerate Cavity Modes For A Distorted Cavity Modes For A Distorted Polystyrene Microsphere, Adam J. Trevitt, Philip J. Wearne, Evan J. Bieske, Michael D. Schuder
Adam Trevitt
Nondegenerate azimuthal morphology-dependent resonances are observed for a distorted, fluorescently labeled polystyrene microsphere levitated in a quadrupole ion trap. Modeling the individual resonances by using perturbation theory allows a determination of quadrupole and octupole distortion parameters. The particle’s shape changes slowly over the course of the measurement and eventually becomes spherical. The morphological changes are facilitated by laser heating of the particle above the polystyrene glass transition temperature. We demonstrate a method of transforming a trapped particle to a sphere and rendering its azimuthal modes degenerate.
Isomer-Specific Product Detection Of Gas-Phase Xylyl Radical Rearrangement And Decomposition Using Vuv Synchrotron Photoionization, Patrick Hemberger, Adam J. Trevitt, Thomas Gerber, Edward Ross, Gabriel Da Silva
Isomer-Specific Product Detection Of Gas-Phase Xylyl Radical Rearrangement And Decomposition Using Vuv Synchrotron Photoionization, Patrick Hemberger, Adam J. Trevitt, Thomas Gerber, Edward Ross, Gabriel Da Silva
Adam Trevitt
Xylyl radicals are intermediates in combustion processes since their parent molecules, xylenes, are present as fuel additives. In this study we report on the photoelectron spectra of the three isomeric xylyl radicals and the subsequent decomposition reactions of the o-xylyl radical, generated in a tubular reactor and probed by mass selected threshold photoelectron spectroscopy and VUV synchrotron radiation. Franck-Condon simulations are applied to augment the assignment of elusive species. Below 1000 K, o-xylyl radicals decompose by hydrogen atom loss to form closed-shell o-xylylene, which equilibrates with benzocyclobutene. At higher temperatures relevant to combustion engines, o-xylylene generates styrene in a multistep …
Hydroxyl Radical Formation In The Gas Phase Oxidation Of Distonic 2-Methylphenyl Radical Cations, Matthew Prendergast, Phillip A. Cooper, Benjamin B. Kirk, Gabriel Da Silva, Stephen J. Blanksby, Adam J. Trevitt
Hydroxyl Radical Formation In The Gas Phase Oxidation Of Distonic 2-Methylphenyl Radical Cations, Matthew Prendergast, Phillip A. Cooper, Benjamin B. Kirk, Gabriel Da Silva, Stephen J. Blanksby, Adam J. Trevitt
Adam Trevitt
The reactions of distonic 4-(N,N,N-trimethylammonium)-2-methylphenyl and 5-(N,N,N-trimethylammonium)-2-methylphenyl radical cations (m/z 149) with O 2 are studied in the gas phase using ion-trap mass spectrometry. Photodissociation (PD) of halogenated precursors gives rise to the target distonic charge-tagged methylphenyl radical whereas collision-induced dissociation (CID) is found to produce unreactive radical ions. The PD generated distonic radicals, however, react rapidly with O2 to form [M + O2]•+ and [M + O2 - OH]•+ ions, detected at m/z 181 and m/z 164, respectively. Quantum chemical calculations using G3SX(MP3) and M06-2X theories are deployed to examine key decomposition pathways of the 5-(N,N,N-trimethylammonium)-2-methylphenylperoxyl radical and rationalise …
Characterisation Of The Ionic Products Arising From Electron Photodetachment Of Simple Dicarboxylate Dianions, Benjamin B. Kirk, Adam J. Trevitt, Berwyck L. Poad, Stephen J. Blanksby
Characterisation Of The Ionic Products Arising From Electron Photodetachment Of Simple Dicarboxylate Dianions, Benjamin B. Kirk, Adam J. Trevitt, Berwyck L. Poad, Stephen J. Blanksby
Adam Trevitt
Much of what we currently understand about the structure and energetics of multiply charged anions in the gas phase is derived from the measurement of photoelectron spectra of simple dicarboxylate dianions. Here we have employed a modified linear ion-trap mass spectrometer to undertake complementary investigations of the ionic products resulting from laser-initiated electron photodetachment of two model dianions. Electron photodetachment (ePD) of the [M-2H]2- dianions formed from glutaric and adipic acid were found to result in a significant loss of ion signal overall, which is consistent with photoelectron studies that report the emission of slow secondary electrons (Xing et al., …