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Articles 1 - 7 of 7
Full-Text Articles in Social and Behavioral Sciences
Rapid Differentiation Of Isomeric Lipids By Photodissociation Mass Spectrometry Of Fatty Acid Derivatives, Huong T. Pham, Adam J. Trevitt, Todd W. Mitchell, Stephen J. Blanksby
Rapid Differentiation Of Isomeric Lipids By Photodissociation Mass Spectrometry Of Fatty Acid Derivatives, Huong T. Pham, Adam J. Trevitt, Todd W. Mitchell, Stephen J. Blanksby
Adam Trevitt
RATIONALE Both traditional electron ionization and electrospray ionization tandem mass spectrometry have demonstrated limitations in the unambiguous identification of fatty acids. In the former case, high electron energies lead to extensive dissociation of the radical cations from which little specific structural information can be obtained. In the latter, conventional collision-induced dissociation (CID) of even-electron ions provides little intra-chain fragmentation and thus few structural diagnostics. New approaches that harness the desirable features of both methods, namely radical-driven dissociation with discrete energy deposition, are thus required. METHODS Herein we describe the derivatization of a structurally diverse suite of fatty acids as 4-iodobenzyl …
Ultraviolet Action Spectroscopy Of Iodine Labeled Peptides And Proteins In The Gas Phase, Benjamin B. Kirk, Adam J. Trevitt, Stephen J. Blanksby, Yuanqi Tao, Benjamin N. Moore, Ryan Julian
Ultraviolet Action Spectroscopy Of Iodine Labeled Peptides And Proteins In The Gas Phase, Benjamin B. Kirk, Adam J. Trevitt, Stephen J. Blanksby, Yuanqi Tao, Benjamin N. Moore, Ryan Julian
Adam Trevitt
Structural investigations of large biomolecules in the gas phase are challenging. Herein, it is reported that action spectroscopy taking advantage of facile carbon-iodine bond dissociation can be used to examine the structures of large molecules, including whole proteins. Iodotyrosine serves as the active chromophore, which yields distinctive spectra depending on the solvation of the side chain by the remainder of the molecule. Isolation of the chromophore yields a double featured peak at 290 nm, which becomes a single peak with increasing solvation. Deprotonation of the side chain also leads to reduced apparent intensity and broadening of the action spectrum. The …
Does Addition Of No2 To Carbon-Centered Radicals Yield Rono Or Rno2? An Investigation Using Distonic Radical Ions, Benjamin B. Kirk, Adam J. Trevitt, Stephen J. Blanksby
Does Addition Of No2 To Carbon-Centered Radicals Yield Rono Or Rno2? An Investigation Using Distonic Radical Ions, Benjamin B. Kirk, Adam J. Trevitt, Stephen J. Blanksby
Adam Trevitt
Nitrogen dioxide is used as a "radical scavenger" to probe the position of carbon-centered radicals within complex radical ions in the gas phase. As with analogous neutral radical reactions, this addition results in formation of an [M + NO2](+) adduct, but the structural identity of this species remains ambiguous. Specifically, the question remains: do such adducts have a nitro-(RNO2) or nitrosoxy-(RONO) moiety, or are both isomers present in the adduct population? In order to elucidate the products of such reactions, we have prepared and isolated three distonic phenyl radical cations and observed their reactions with nitrogen dioxide in the gas …
Product Detection Of The Ch Radical Reaction With Acetaldehyde, Fabien Goulay, Adam Trevitt, John Savee, Jordy Bouwman, David Osborn, Craig Taatjes, Kevin Wilson, Stephen Leone
Product Detection Of The Ch Radical Reaction With Acetaldehyde, Fabien Goulay, Adam Trevitt, John Savee, Jordy Bouwman, David Osborn, Craig Taatjes, Kevin Wilson, Stephen Leone
Adam Trevitt
The reaction of the methylidyne radical (CH) with acetaldehyde (CH3CHO) is studied at room temperature and at a pressure of 4 Torr (533.3 Pa) using a multiplexed photoionization mass spectrometer coupled to the tunable vacuum ultraviolet synchrotron radiation of the Advanced Light Source at Lawrence Berkeley National Laboratory. The CH radicals are generated by 248 nm multiphoton photolysis of CHBr3 and react with acetaldehyde in an excess of helium and nitrogen gas flow. Five reaction exit channels are observed corresponding to elimination of methylene (CH2), elimination of a formyl radical (HCO), elimination of carbon monoxide (CO), elimination of a methyl …
Uv Photodissociation Action Spectroscopy Of Haloanilinium Ions In A Linear Quadrupole Ion Trap Mass Spectrometer, Christopher S. Hansen, Benjamin B. Kirk, Stephen J. Blanksby, Richard A. J O'Hair, Adam J. Trevitt
Uv Photodissociation Action Spectroscopy Of Haloanilinium Ions In A Linear Quadrupole Ion Trap Mass Spectrometer, Christopher S. Hansen, Benjamin B. Kirk, Stephen J. Blanksby, Richard A. J O'Hair, Adam J. Trevitt
Adam Trevitt
UV-vis photodissociation action spectroscopy is becoming increasingly prevalent because of advances in, and commercial availability of, ion trapping technologies and tunable laser sources. This study outlines in detail an instrumental arrangement, combining a commercial ion-trap mass spectrometer and tunable nanosecond pulsed laser source, for performing fully automated photodissociation action spectroscopy on gas-phase ions. The components of the instrumentation are outlined, including the optical and electronic interfacing, in addition to the control software for automating the experiment and performing online analysis of the spectra. To demonstrate the utility of this ensemble, the photodissociation action spectra of 4-chloroanilinium, 4-bromoanilinium, and 4-iodoanilinium cations …
Formation Of Dimethylketene And Methacrolein By Reaction Of The Ch Radical With Acetone, Fabien Goulay, Adeeb Derakhshan, Eamonn Maher, Adam J. Trevitt, John D. Savee, Adam M. Scheer, David L. Osborn, Craig A. Taatjes
Formation Of Dimethylketene And Methacrolein By Reaction Of The Ch Radical With Acetone, Fabien Goulay, Adeeb Derakhshan, Eamonn Maher, Adam J. Trevitt, John D. Savee, Adam M. Scheer, David L. Osborn, Craig A. Taatjes
Adam Trevitt
The reaction of the methylidyne radical (CH) with acetone ((CH3)2CO) is studied at room temperature and at a pressure of 4 Torr (533.3 Pa) using a multiplexed photoionization mass spectrometer coupled to the tunable vacuum ultraviolet synchrotron radiation of the Advanced Light Source at Lawrence Berkeley National Laboratory. The CH radicals are generated by 248 nm multiphoton photolysis of bromoform and react with acetone in an excess of helium and nitrogen gas flow. The main observed reaction exit channel is elimination of a hydrogen atom to form C4H6O isomers. Analysis of photoionization spectra identifies dimethylketene and methacrolein as the only …
Isolation And Characterization Of Charge-Tagged Phenylperoxyl Radicals In The Gas Phase: Direct Evidence For Products And Pathways In Low Temperature Benzene Oxidation, Benjamin Kirk, David Harman, Hilkka Kenttamaa, Adam Trevitt, Stephen Blanksby
Isolation And Characterization Of Charge-Tagged Phenylperoxyl Radicals In The Gas Phase: Direct Evidence For Products And Pathways In Low Temperature Benzene Oxidation, Benjamin Kirk, David Harman, Hilkka Kenttamaa, Adam Trevitt, Stephen Blanksby
Adam Trevitt
The phenylperoxyl radical has long been accepted as a critical intermediate in the oxidation of benzene and an archetype for arylperoxyl radicals in combustion and atmospheric chemistry. Despite being central to many contemporary mechanisms underpinning these chemistries, reports of the direct detection or isolation of phenylperoxyl radicals are rare and there is little experimental evidence connecting this intermediate with expected product channels. We have prepared and isolated two charge-tagged phenyl radical models in the gas phase [i.e., 4-(N,N,N-trimethylammonium)phenyl radical cation and 4-carboxylatophenyl radical anion] and observed their reactions with dioxygen by ion-trap mass spectrometry. Measured reaction rates show good agreement …