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Full-Text Articles in Physical Sciences and Mathematics
Average Mass Scan Of The Total Ion Chromatogram Versus Percentage Chemical Composition In Multivariate Statistical Comparison Of Complex Volatile Mixtures, Niko Radulovic, Polina Blagojevic, Danielle Skropeta
Average Mass Scan Of The Total Ion Chromatogram Versus Percentage Chemical Composition In Multivariate Statistical Comparison Of Complex Volatile Mixtures, Niko Radulovic, Polina Blagojevic, Danielle Skropeta
Danielle Skropeta
The analysis of complex volatile mixtures by gas chromatography-mass spectrometry (GC-MS) is a time-consuming process. It involves separation and identification of the components based on their retention times and fragmentation patterns, followed by determination of their relative percentages from integration of their peak areas. Herein we show that multivariate statistical analysis of the relative abundances of the m/z values obtained from the average mass scans (AMS) of the complex mixture is a faster and potentially more reliable method of assessing these mixtures. To achieve this, 15 model complex mixtures, were prepared comprising varying amounts of 10 different constituents. The AMS …
Effect Of Protein Stabilization On Charge State Distribution In Positive- And Negative Ion Electrospray Ionization Mass Spectra, Stephen J. Watt, Margaret Sheil, Jennifer L. Beck, Pavel Prosselkov, Gottfried Otting, Nicholas E. Dixon
Effect Of Protein Stabilization On Charge State Distribution In Positive- And Negative Ion Electrospray Ionization Mass Spectra, Stephen J. Watt, Margaret Sheil, Jennifer L. Beck, Pavel Prosselkov, Gottfried Otting, Nicholas E. Dixon
Professor Nick E Dixon
Changes in protein conformation are thought to alter charge state distributions observed in electrospray ionization mass spectra (ESI-MS) of proteins. In most cases, this has been demonstrated by unfolding proteins through acidification of the solution. This methodology changes the properties of the solvent so that changes in the ESI-MS charge envelopes from conformational changes are difficult to separate from the effects of changing solvent on the ionization process. A novel strategy is presented enabling comparison of ESI mass spectra of a folded and partially unfolded protein of the same amino acid sequence subjected to the same experimental protocols and conditions. …
Infrared Spectra Of Mass-Selected Mg+-H2 And Mg +-D2 Complexes, Viktoras Dryza, Berwyck L. Poad, Evan J. Bieske
Infrared Spectra Of Mass-Selected Mg+-H2 And Mg +-D2 Complexes, Viktoras Dryza, Berwyck L. Poad, Evan J. Bieske
Berwyck L. J. Poad
Rotationally resolved infrared spectra of Mg(+)-H(2) and Mg(+)-D(2) are recorded in the H-H (4025-4080 cm(-1)) and D-D (2895-2945 cm(-1)) stretch regions by monitoring Mg(+) photofragments. The nu(HH) and nu(DD) transitions of Mg(+)-H(2) and Mg(+)-D(2) are red-shifted by 106.2 +/- 1.5 and 76.0 +/- 0.1 cm(-1) respectively from the fundamental vibrational transitions of the free H(2) and D(2) molecules. The spectra are consistent with a T-shaped equilibrium structure in which the Mg(+) ion interacts with a slightly perturbed H(2) or D(2) molecule. From the spectroscopic constants, a vibrationally averaged intermolecular separation of 2.716 A (2.687 A) is deduced for the ground …
Identification Of Phospholipids In Human Meibum By Nano-Electrospray Ionisation Tandem Mass Spectrometry, Jennifer T. Saville, Zhenjun Zhao, Mark Dp Willcox, Manjula A. Ariyavidana, Stephen J. Blanksby, Todd W. Mitchell
Identification Of Phospholipids In Human Meibum By Nano-Electrospray Ionisation Tandem Mass Spectrometry, Jennifer T. Saville, Zhenjun Zhao, Mark Dp Willcox, Manjula A. Ariyavidana, Stephen J. Blanksby, Todd W. Mitchell
Stephen Blanksby
Meibum is believed to be the major source of tear !lm lipids, which are vital in the prevention of excessevaporation of the aqueous phase. The complete lipid composition of meibum has yet to be established.While earlier studies reported the presence of phospholipids in human meibum, recent mass spectrometricstudies have not detected them. In this study we use electrospray ionisation tandem massspectrometry to investigate the presence of phospholipids in meibum and provide comparison to thephospholipid pro!le of tears.Lipids were extracted from human meibum and tear samples using standard biphasic methods andanalysed by nano-electrospray ionisation tandem mass spectrometry using targeted ion scans. …
Ozone Induced Dissociation: Elucidation Of Double Bond Position Within Mass-Selected Lipid Ions, Michael C. Thomas, Todd W. Mitchell, David G. Harman, Jane M. Deeley, Jessica R. Nealon, Stephen J. Blanksby
Ozone Induced Dissociation: Elucidation Of Double Bond Position Within Mass-Selected Lipid Ions, Michael C. Thomas, Todd W. Mitchell, David G. Harman, Jane M. Deeley, Jessica R. Nealon, Stephen J. Blanksby
Stephen Blanksby
Ions formed from lipids during electrospray ionization of crude lipid extracts have been mass-selected within a quadrupole linear ion trap mass spectrometer and allowed to react with ozone vapor. Gas-phase ion−molecule reactions between unsaturated lipid ions and ozone are found to yield two primary product ions for each carbon−carbon double bond within the molecule. The mass-to-charge ratios of these chemically induced fragments are diagnostic of the position of unsaturation within the precursor ion. This novel analytical technique, dubbed ozone-induced dissociation (OzID), can be applied both in series and in parallel with conventional collision-induced dissociation (CID) to provide near-complete structural assignment …
Direct Detection Of Additives And Degradation Products From Polymers By Liquid Extraction Surface Analysis Employing Chip-Based Nanospray Mass Spectrometry, Martin Paine, Phillip Barker, Shane A. Maclaughlin, Todd W. Mitchell, Stephen J. Blanksby
Direct Detection Of Additives And Degradation Products From Polymers By Liquid Extraction Surface Analysis Employing Chip-Based Nanospray Mass Spectrometry, Martin Paine, Phillip Barker, Shane A. Maclaughlin, Todd W. Mitchell, Stephen J. Blanksby
Stephen Blanksby
Rationale: Polymer-based surface coatings in outdoor applications experience accelerated degradation due to exposure to solar radiation, oxygen and atmospheric pollutants. These deleterious agents cause undesirable changes to the polymers aesthetic and mechanical properties reducing its lifetime. The use of antioxidants such as hindered amine light stabilisers (HALS) retard these degradative processes, however, mechanisms for HALS action and polymer degradation are poorly understood. Methods: Detection of the hindered amine light stabiliser (HALS) TINUVIN®123 (bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate) and the polymer degradation products directly from a polyester-based coil coating was achieved by liquid extraction surface analysis (LESA) coupled to a triple quadrupole QTRAP® …
Tandem Mass Spectrometry Reveals The Quaternary Organization Of Macromolecular Assemblies, J L Benesch, Andrew Aquilina, Brandon T. Ruotolo, Frank Sobott, C V Robinson
Tandem Mass Spectrometry Reveals The Quaternary Organization Of Macromolecular Assemblies, J L Benesch, Andrew Aquilina, Brandon T. Ruotolo, Frank Sobott, C V Robinson
J. A. Aquilina
The application of mass spectrometry (MS) to the study of progressively larger and more complex macromolecular assemblies is proving increasingly useful for structural biologists. The scope of this approach has recently been widened through the application of a tandem MS procedure. This two-step technique involves the selection of specific assemblies in the gas phase, and inducing their dissociation through collisions with argon atoms. Here we investigate the mechanism of this process and show that dissociation of subunits from a macromolecular assembly follows a sequential pathway, with the partitioning of charge between the dissociation products governed primarily by their relative surface …
The Epididymal Soluble Prion Protein Forms A High-Molecular-Mass Complex In Association With Hydrophobic Proteins, Heath W. Ecroyd, Maya Belghazi, Jean-Louis Dacheux, Jean-Luc Gatti
The Epididymal Soluble Prion Protein Forms A High-Molecular-Mass Complex In Association With Hydrophobic Proteins, Heath W. Ecroyd, Maya Belghazi, Jean-Louis Dacheux, Jean-Luc Gatti
Heath Ecroyd
We have shown previously that a 'soluble' form of PrP (prion protein), not associated with membranous vesicles, exists in the male reproductive fluid [Ecroyd, Sarradin, Dacheux and Gatti (2004) Biol. Reprod. 71, 993-1001]. Attempts to purify this 'soluble' PrP indicated that it behaves like a high-molecular-mass complex of more than 350 kDa and always co-purified with the same set of proteins. The main associated proteins were sequenced by MS and were found to match to clusterin (apolipoprotein J), BPI (bacterial permeability-increasing protein), carboxylesterase-like urinary excreted protein (cauxin), beta-mannosidase and beta-galactosidase. Immunoblotting and enzymatic assay confirmed the presence of clusterin and …
Identification Of Abundant Alkyl Ether Glycerophospholipids In The Human Lens By Tandem Mass Spectrometry Techniques, Roger J. Truscott, Jane Deeley, Todd W. Mitchell, Michael Thomas, Stephen J. Blanksby
Identification Of Abundant Alkyl Ether Glycerophospholipids In The Human Lens By Tandem Mass Spectrometry Techniques, Roger J. Truscott, Jane Deeley, Todd W. Mitchell, Michael Thomas, Stephen J. Blanksby
Stephen Blanksby
Previous studies have shown that the human lens contains glycerophospholipids with ether linkages. These lipids differ from conventional glycerophospholipids in that the sn-1 substituent is attached to the glycerol backbone via an 1-O-alkyl or an 1-O-alk-1'-enyl ether rather than an ester bond. The present investigation employed a combination of collision-induced dissociation (CID) and ozone-induced dissociation (OzID) to unambiguously distinguish such 1-O-alkyl and 1-O-alk-1'-enyl ethers. Using these methodologies the human lens was found to contain several abundant 1-O-alkyl glycerophos-phoethanolamines, including GPEtn(16:0e/9Z-18:1), GPEtn(11Z-18:1e/9Z-18:1), and GPEtn(18:0e/9Z-18:1), as well as a related series of unusual 1-O-alkyl glycerophosphoserines, including GPSer(16:0e/9Z-18:1), GPSer(11Z-18:1e/9Z-18:1), GPSer(18:0e/9Z-18:1) that to our …
Identification Of Abundant Alkyl Ether Glycerophospholipids In The Human Lens By Tandem Mass Spectrometry Techniques, Roger J. Truscott, Jane Deeley, Todd W. Mitchell, Michael Thomas, Stephen J. Blanksby
Identification Of Abundant Alkyl Ether Glycerophospholipids In The Human Lens By Tandem Mass Spectrometry Techniques, Roger J. Truscott, Jane Deeley, Todd W. Mitchell, Michael Thomas, Stephen J. Blanksby
Stephen Blanksby
Previous studies have shown that the human lens contains glycerophospholipids with ether linkages. These lipids differ from conventional glycerophospholipids in that the sn-1 substituent is attached to the glycerol backbone via an 1-O-alkyl or an 1-O-alk-1'-enyl ether rather than an ester bond. The present investigation employed a combination of collision-induced dissociation (CID) and ozone-induced dissociation (OzID) to unambiguously distinguish such 1-O-alkyl and 1-O-alk-1'-enyl ethers. Using these methodologies the human lens was found to contain several abundant 1-O-alkyl glycerophos-phoethanolamines, including GPEtn(16:0e/9Z-18:1), GPEtn(11Z-18:1e/9Z-18:1), and GPEtn(18:0e/9Z-18:1), as well as a related series of unusual 1-O-alkyl glycerophosphoserines, including GPSer(16:0e/9Z-18:1), GPSer(11Z-18:1e/9Z-18:1), GPSer(18:0e/9Z-18:1) that to our …