Alan G. Marshall

Florida State University

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Document Type

Co-Authors

Ryan P. Rodgers

National High Magnetic Field Laboratory

143

Christopher L. Hendrickson

National High Magnetic Field Laboratory

142

Mark R. Emmett

The University of Texas Medical Branch at Galveston

Shenheng Guan

Rapt Therapeutics (United States)

Amy M. McKenna

National High Magnetic Field Laboratory

Greg T. Blakney

National High Magnetic Field Laboratory

Michael A. Freitas

The Ohio State University

Jeremiah M. Purcell

Florida State University

John Quinn

Royal College of Surgeons in Ireland

Helen J. Cooper

University of Birmingham

Cooperative Institutions

Florida State University

271

National High Magnetic Field Laboratory

222

The Ohio State University

University of Florida

Centre National de la Recherche Scientifique

Harvard University

Pfizer (United States)

Chinese Academy of Sciences

Northwestern University

Scripps Research Institute

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An NMR structural study of 2‐fluoropyridine dissolved in a nematic solvent

Organic Magnetic Resonance (1979)

E. Elliott Burnell Alan G. Marshall D. Christopher Roe

Abstract The proton NMR spectrum of 2‐fluoropyridine partially oriented in a nematic phase has been analyzed, and the geometry of the proton and fluorine skeleton and the order matrix have been determined. The structure does not differ significantly from that of pyridine in a nematic solvent, and the largest positive order parameter axis lies approximately along the CF bond direction in the molecule.

Proton NMR

10.1002/mrc.1270120509

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Citations (1)

Compositional Characterization of Bitumen/Water Emulsion Films by Negative- and Positive-Ion Electrospray Ionization and Field Desorption/Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Energy & Fuels (2007)

Lateefah A. Stanford Ryan P. Rodgers Alan G. Marshall Jan Czarnecki Xin A. Wu

By means of electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT−ICR MS) and automated field desorption/ionization (FD) FT−ICR MS, we identify nonvolatile nonpolar, polar acidic, and basic water-in-bitumen emulsion film stabilizers. Highly condensed aromatic basic, nonpolar, and acidic asphaltene multilayered films stabilize emulsions near or at critical bitumen concentration for asphaltene flocculation. Solvent diluent added beyond the critical dilution concentration precipitates highly condensed acidic, all basic, and most neutral species from the oil/water interface. The most abundant classes in high bitumen concentration emulsion films include neutral pure hydrocarbons and S, acidic O2 and O2S, and basic N and NS heteroatom classes. Highly abundant low bitumen concentration emulsion film stabilizers include acidic O2, O4, and O3S classes.

Asphaltene

10.1021/ef060291i

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Citations (113)

Mapping of protein:protein contact surfaces by hydrogen/deuterium exchange, followed by on-line high-performance liquid chromatography–electrospray ionization fourier-transform ion-cyclotron-resonance mass analysis

Journal of Chromatography A (2002)

TuKiet T. Lam Jason Lanman Mark R. Emmett Christopher L. Hendrickson Alan G. Marshall

Hydrogen–deuterium exchange

Ion cyclotron resonance

Amide

10.1016/s0021-9673(02)01357-2

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Citations (52)

Improved Mass Analysis of Oligoribonucleotides by ¹³C, ¹⁵N Double Depletion and Electrospray Ionization FT-ICR Mass Spectrometry

Analytical Chemistry (2004)

Ying Xiong Kersten T. Schroeder Nancy L. Greenbaum Christopher L. Hendrickson Alan G. Marshall

13C, 15N doubly depleted 32-ribonucleotide was synthesized enzymatically by in vitro transcription from nucleoside triphosphates isolated from E. coli grown in a minimal medium containing 12C, 14N-enriched glucose and ammonium sulfate. Following purification and desalting by reversed-phase HPLC, buffer exchange with Microcon YM-3, and ethanol precipitation, electrospray ionization Fourier transform ion cyclotron resonance mass spectra revealed greatly enhanced abundance of monoisotopic ions (by a factor of ∼100) and a narrower isotopic distribution with higher signal-to-noise ratio. The abrupt onset and high magnitude of the monoisotopic species promise to facilitate accurate mass measurement of RNA's.

Monoisotopic mass

10.1021/ac030299e

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Citations (9)

Evaluation of the binding constants, bound chemical shifts, and equilibrium stoichiometry for the association of lanthanide shift reagents with carbohydrate derivatives

Carbohydrate Research (1973)

Anita L. Arduini Ian M. Armitage Laurance D. Hall Alan G. Marshall

Europium

Stoichiometry

Chemical shift

10.1016/s0008-6215(00)86190-x

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Citations (15)

Kinetic Determination of Potassium Affinities by IRMPD: Elucidation of Precursor Ion Structures

The Journal of Physical Chemistry A (2009)

Mathias Schäfer Miriam K. Drayß Dirk Blunk Jeremiah M. Purcell Christopher L. Hendrickson

Dissociation kinetics of the K(+) loss reaction of three potassiated tertiary amino acids (Scheme 1) were studied by infrared multiple photon dissociation (IRMPD) in a Fourier transform ion cyclotron resonance (FT ICR)-MS instrument. The aim of the study was to probe if a kinetic study by IRMPD can yield useful information on the ion structure of the precursor ion species. The measured activation energy values determined by IRMPD are related to the potassium affinity, DeltaH(K(+)), of N-methyl proline determined by threshold collision-induced dissociation experiments. By appropriate scaling with this reference value, the experimentally determined activation energy values for the K(+) loss are transformed into respective potassium affinities, DeltaH(K(+))(IRMPD). These values match the calculated potassium affinity values for salt bridge (SB) structures, DeltaH(K(+))(SB), substantially better than those for canonical structures with a single formal charge site (charge solvation (CS)), thereby allowing structure identification. This conclusion is consistent with other spectroscopic data, which yielded unambiguous evidence of these tertiary amino acids adopting SB structures in the gas phase. This study demonstrates that IRMPD can be applied to determine individual ion structures in the gas phase, given that adequate reference values are available for proper scaling.

Affinities

Infrared multiphoton dissociation

10.1021/jp903232y

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Citations (8)

Rye House plotters (act. 1683)

Oxford University Press eBooks (2005)

Alan G. Marshall

Plotter

10.1093/ref:odnb/93794

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Citations (0)

Mass-selective ion accumulation and fragmentation in a linear octopole ion trap external to a fourier transform ion cyclotron resonance mass spectrometer

International Journal of Mass Spectrometry (2000)

Yang Wang Stone D.‐H. Shi Christopher L. Hendrickson Alan G. Marshall

Ion cyclotron resonance

Quadrupole ion trap

Quadrupole mass analyzer

Fragmentation

Hybrid mass spectrometer

Selected ion monitoring

Top-down proteomics

10.1016/s1387-3806(00)00177-9

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Citations (52)

Photoinduced Oxidation and Polymerization in Oil-Soluble Products and Interfacial Material from Petroleum Weathering

Energy & Fuels (2025)

Joseph W. Frye Martha L. Chacón-Patiño Alan G. Marshall Ryan P. Rodgers

Photooxidation is recognized as one of the major weathering processes in petroleum upon oil spills. Previous work with solar simulator microcosms has shown that petroleum weathering can be replicated in the laboratory with a variety of sample types and weathering periods. The microcosms can be scaled up to produce large amounts of photo-oxidized materials that enable subsequent chromatographic separations, which provide more comprehensive knowledge of its complex molecular composition. The work herein focuses on the use of a solar simulator to generate photo-oxidized compounds from a heavy vacuum gas oil for subsequent separations by 2 methods: modified aminopropyl silica extraction to target acidic species and extraction of interfacially active compounds via the "wet silica" method. Molecular characterization was performed by negative-ion (−) electrospray ionization ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (21 T FT-ICR MS). These results uniquely demonstrate that water-soluble photo-oxidation products are not the only phase that feature the products of photoirradiation-driven polymerization reactions. Separations allowed for the expansion of the molecular coverage, which revealed previously undetected species that were masked by the lower molecular weight acidic species that were preferentially ionized in the broadband analysis of unfractionated materials. Thus, the separations facilitated the detection of abundant oil-soluble photopolymerization products in acidic fractions of high carbon number and aromaticity. Interfacially active material (IM) also reveals minor polymerization products in later-eluting acidic fractions.

10.1021/acs.energyfuels.4c03107

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Citations (1)

<title>Correlation between solution and gas-phase protein conformation: H/D exchange, IRMPD, and ESI FT-ICR MS</title>

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2000)

Michael A. Freitas Christopher L. Hendrickson Alan G. Marshall

Infrared multiphoton dissociation (IRMPD) of the hydrogen/deuterium (H/D) exchanged 12+ charge state of gas-phase bovine ubiquitin was performed on a Fourier transform ion cyclotron resonance mass spectrometer. The H/D exchange of the 12+ charge state revealed two distinct isotopic distributions indicating the presence of at least two distinct conformations of the 12+ charge state. Following H/D exchange, IRMPD was used to dissociate the conformations. The fragments clearly showed little or no deuterium scrambling as evidenced by a nonstatistical distribution of deuterium incorporation. Analysis of the deuterium incorporation for the five most abundant fragment ions indicated a slow exchanging region of the fast exchanging conformation that corresponds to a stable (beta) - sheet observed by NMR in alcoholic solutions. The data suggest that protection of the amide hydrogens in the (beta) -sheet may result in the observed slow exchange rate and provides further evidence for the retention of secondary structure in gas phase.

Infrared multiphoton dissociation

Hydrogen–deuterium exchange

Ion cyclotron resonance

10.1117/12.380495

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Citations (3)