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Journal of Mass Spectrometry: JMS

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https://read.qxmd.com/read/30989769/electric-modeling-and-characterization-of-pulsed-high-voltage-nano-electrospray-ionization-sources-by-a-miniature-ion-trap-mass-spectrometer
#1
Zuqiang Xu, Hanyan Wu, Yang Tang, Wei Xu, Yanbing Zhai
A better understanding of nano-electrospray ionization (nano-ESI) would be beneficial in further improving the performances of nano-ESI. In this work, the pulsed high voltage (HV) nano-ESI has been electrically modeled and then systematically characterized by both voltage-current and mass spectrometry measurements. First the equivalent resistance of a nano-ESI source changes with respect to both emitter tip diameter and the HV applied. Increased voltage could improve both spray current and ionization efficiency of the pulsed HV nano-ESI...
April 15, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30989744/gas-phase-functionalized-carbon-carbon-coupling-reactions-catalyzed-by-ni-ii-complexes
#2
Elettra Piacentino, Edwin Rodrigues, Kevin Parker, Thomas M Gilbert, Richard A J O'Hair, Victor Ryzhov
Gas-phase C-C coupling reactions mediated by Ni (II) complexes were studied using a linear quadrupole ion trap mass spectrometer. Ternary nickel cationic carboxylate complexes, [(phen)Ni (OOCR1 )]+ (where phen = 1,10-phenanthroline) were formed by electrospray ionization. Upon collision-induced dissociation (CID), they extrude CO2 forming the organometallic cation [(phen)Ni(R1 )]+ , which undergoes gas-phase ion-molecule reactions (IMR) with acetate esters CH3 COOR2 to yield the acetate complex [(phen)Ni (OOCCH3 )]+ and a C-C coupling product R1 -R2 ...
April 15, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30980780/assigning-the-esi-mass-spectra-of-organometallic-and-coordination-compounds
#3
J Scott McIndoe, Krista L Vikse
ESI mass spectrometry is a useful technique for solving organometallic and coordination chemistry characterization problems that are difficult to address using traditional methods. However, assigning the ESI mass spectra of organometallic compounds can be challenging and the considerations involved in doing so are quite different from assigning the mass spectrum of a purely organic sample. This is a tutorial article for organometallic/coordination chemists using ESI-MS to analyze pure compounds or reaction mixtures...
April 13, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30942557/thermodynamic-properties-of-gaseous-cerium-phosphate-studied-by-knudsen-effusion-mass-spectrometry
#4
S I Lopatin, S M Shugurov, A I Panin
Gaseous CePO2 has been identified by Knudsen effusion mass spectrometry during vaporization of CeO2 and magnesium diphosphate from tungsten double two-temperature effusion cell. Structure and molecular parameters of gaseous cerium phosphate under study were determined using quantum chemical calculations. On the basis of equilibrium constants measured for gas-phase reaction, standard formation enthalpy of CePO2 was determined to be -508±41 kJ⋅mol-1 at the temperature 298 K.
April 3, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30912235/the-unusual-fragmentation-of-long-chain-feruloyl-esters-under-negative-ion-electrospray-conditions
#5
Jürgen Schmidt, Dietmar Kuck, Katrin Franke, Haider Sultani, Annegret Laub, Ludger A Wessjohann
Long-chain ferulic acid esters, such as eicosyl ferulate (1), show a complex and analytically valuable fragmentation behavior under negative-ion electrospay collision-induced dissociation ((-)-ESI-CID) mass spectrometry, as studied by use of a high-resolution (Orbitrap) mass spectrometer. In a strong contrast to the very simple fragmentation of the [M + H]+ ion, which is discussed briefly, the deprotonated molecule, [M - H]- , exhibits a rich secondary fragmentation chemistry. It first loses a methyl radical (MS2 ) and the ortho-quinoid [M - H - Me]-• radical anion thus formed then dissociates by loss of an extended series of neutral radicals, Cn H2n+1 • (n = 0-16) from the long alkyl chain, in competition with the expulsion of CO and CO2 (MS3 )...
March 26, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30908762/development-and-comparison-of-liquid-liquid-extraction-and-accelerated-solvent-extraction-methods-for-quantitative-analysis-of-chloramphenicol-thiamphenicol-florfenicol-and-florfenicol-amine-in-poultry-eggs
#6
Bo Wang, Maoda Pang, Xia Zhao, Kaizhou Xie, Peiyang Zhang, Genxi Zhang, Tao Zhang, Xuezhong Liu, Guojun Dai
Accelerated solvent extraction was investigated as a novel alternative technology for the separation and quantitative analysis of chloramphenicol, thiamphenicol, florfenicol and florfenicol amine from poultry eggs, and the results were compared with the results of liquid-liquid extraction. Rapid quantification of the target compounds was carried out by ultra-performance liquid chromatography-electrospray ionization tandem triple quadrupole mass spectrometry. This optimized method was validated according to the requirements defined by the European Union and the United States Food and Drug Administration...
March 25, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30907977/detection-and-assignment-of-inorganic-aqueous-polymers-relevant-to-environmental-nanogeoscience-by-direct-infusion-electrospray-ionization-mass-spectrometry
#7
Mercedes Becerra-Herrera, Sergio D Moraga, Pablo Cruz-Hernández, Rodrigo Molinas, Pablo Richter, Manuel A Caraballo
Inorganic polymers in aqueous solutions are being proposed as essential components in new theories concerning non-classical nucleation and growth of nanominerals relevant to environmental nanogeosciences. The study of those complex natural processes requires multi-technique analytical approaches able to characterize the solutions and their constituents (solutes, oligomers, polymers, clusters and nanominerals) from atomic to micrometric scales. A novel analytical approach involving an electrospray ionization source (ESI) coupled to time-of-flight mass spectrometry (TOF/MS) was developed to identify inorganic polymers in aqueous solution...
March 25, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30900786/dempster-s-descendants-the-core-of-the-development-of-mass-spectrometry
#8
Keith A Nier
The work of Arthur Dempster generally has been considered significant but of less importance in the growth of mass spectrometry than that of Francis Aston, and as essentially limited to the pre-WW II era. The development of mass spectrometry, however, as distinct from nuclear science, was shaped far more by Dempster than by Aston. This influence is seen in several aspects of instrument design and practice and it has continued into the twenty-first century.
March 22, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30884544/theoretical-chemical-ionization-rate-constants-of-the-concurrent-reactions-of-hydronium-ions-h-3-o-and-oxygen-ions-o-2-with-selected-organic-iodides
#9
Rafal S Strekowski, Coralie Alvarez, Jeanne Petrov-Stojanović, Denis Hagebaum-Reignier, Henri Wortham
Short chain volatile iodinated organic compounds (VIOCs) are of great importance in many fields that include atmospheric chemistry, agriculture and environmental chemistry related to nuclear power plant safety. Proton-transfer-reaction mass spectrometry (PTR-MS) allows for fast, sensitive and on-line quantification of VIOCs if the chemical ionization (CI) reaction rate constants are known. In this work, the theoretical CI collision rates for the reactions of hydronium ions (H3 O+ ) and oxygen ions ( <mml:math xmlns:mml="http://www...
March 18, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30882954/an-efficient-solution-for-resolving-itraq-and-tmt-channel-crosstalk
#10
Brian C Searle, Alfred L Yergey
Isobaric tagging reagents such as iTRAQ and TMT typically have isotopic impurities that cause significant crosstalk between channels. Here we present an efficient solution to compensate for channel crosstalk using linear algebra and find that it is between 20x and 120x faster than previous methods. We also find that the effects of channel crosstalk are as important to manage as the effects of ratio compression due to precursor impurities, and we have released an open-source tool to perform both types of calculations...
March 18, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30869178/dipolar-dc-induced-collisional-activation-of-non-dissociated-electron-transfer-products
#11
Sarju Adhikari, Eric T Dziekonski, Frank A Londry, Scott A McLuckey
The application of electron transfer and dipolar direct current induced collisional activation (ET-DDC) for enhanced sequence coverage of peptide/protein cations is described. A DDC potential is applied across one pair of opposing rods in the high-pressure collision cell of a hybrid quadrupole/time-of-flight tandem mass spectrometer (QqTOF) to induce collisional activation, in conjunction with electron transfer reactions. As a broadband technique, DDC can be employed for the simultaneous collisional activation of all the first-generation charge reduced precursor ions (e...
March 14, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30860640/formation-of-multimeric-steroid-metal-adducts-and-implications-for-isomer-mixture-separation-by-traveling-wave-ion-mobility-spectrometry
#12
Alana L Rister, Tiana L Martin, Eric D Dodds
Steroid analysis is essential to the fields of medicine and forensics, but such analyses can present some complex analytical challenges. While chromatographic methods require long acquisition times and often provide incomplete separation, ion mobility spectrometry (IMS) as coupled to mass spectrometry (MS) has demonstrated significant promise for the separation of steroids, particularly in concert with metal adduction and multimerization. In this study, traveling wave ion mobility spectrometry (TWIMS) was employed to separate multimer steroid metal adducts of isomers in mixtures...
March 12, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30860300/mechanistic-insights-into-intramolecular-phosphate-group-transfer-during-collision-induced-dissociation-of-phosphopeptides
#13
Laura S Bailey, Mélanie Alves, Nicolas Galy, Amanda L Patrick, Nicolas C Polfer
We report on the rearrangement chemistry of model phosphorylated peptides during collision-induced dissociation (CID), where intramolecular phosphate group transfers are observed from donor to acceptor residues. Such "scrambling" could result in inaccurate modification localization, potentially leading to misidentifications. Systematic studies presented herein provide mechanistic insights for the unusually high phosphate group rearrangements presented some time ago by Reid and co-workers (Proteomics 2013, 13 (6), 964-973)...
March 12, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30849787/influence-of-the-amino-acid-composition-on-the-ionization-efficiencies-of-small-peptides
#14
Piia Liigand, Karl Kaupmees, Anneli Kruve
Electrospray ionization is widely used to generate gas phase ions from a variety of molecules ranging from small ions to large proteins, while the ionization mechanism is claimed to depend on the size of the molecule. For small molecules, the ionization efficiency, the amount of gas phase ions produced in the electrospray process, depends on the properties of the compound. Here we show that the amino acid composition also influences the ionization efficiency of the oligopeptide. Additionally, we show that the ionization efficiencies of oligopeptides consisting of more than 5 amino acid residues are very similar to one another and assuming equal ionization efficiencies is feasible...
March 8, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30828905/are-formalin-fixed-and-paraffin-embedded-tissues-fit-for-proteomic-analysis
#15
Malte Bayer, Linus Angenendt, Christoph Schliemann, Wolfgang Hartmann, Simone König
Formalin-fixed and paraffin-embedded (FFPE)-tissue archives are potential treasure troves in the search for clinically interesting specimens. However, while the FFPE-treatment provides excellent conservation of the three-dimensional structure of the tissue and prevents degradation over decades, it also introduces numerous non-specific and irreversible protein modifications. In this study, we have evaluated several published workflows for FFPE-tissue by fit-for-purpose proteomics technologies. We demonstrate that many protein modifications and cross-links remain after treatment and conclude that the proteomics of FFPE-tissue is of value, but clear-cut limitations must be kept in mind...
March 3, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30817044/direct-flow-injection-profiling-of-acyl-glycerols-from-food-products-using-isopropanol-as-solvent
#16
Edoardo Longo, Ksenia Morozova, Sine Yener, Emanuele Boselli, Franco Biasioli, Matteo Scampicchio
This work proposes a novel method for the direct flow injection profiling of acyl glycerols in edible oils and fats without preliminary extraction and consequent reconstitution in the injection solvent. The work exploits the outstanding performance of high-resolution mass spectrometry to target unique elemental compositions even in the most complex matrices. The performance of isopropanol as the unique solvent for both the solubilization and analysis of acyl glycerols was investigated in comparison with other classical methods involving preliminary extractions, sample recovery and analysis...
February 28, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30801903/investigation-of-activation-energies-for-dissociation-of-host-guest-complexes-in-the-gas-phase-using-low-energy-collision-induced-dissociation
#17
Parisa Bayat, David Gatineau, Denis Lesage, Sina Marhabaie, Alexandre Martinez, Richard B Cole
A low-energy collision induced dissociation CID (low-energy CID) approach that can determine both activation energy and activation entropy has been used to evaluate gas-phase binding energies of host-guest (H-G) complexes of a heteroditopic hemicryptophane cage host (Zn (II)@1) with a series of biologically-relevant guests. In order to use this approach, preliminary calibration of the effective temperature of ions undergoing resonance excitation is required. This was accomplished by employing blackbody infrared radiative dissociation (BIRD) which allows direct measurement of activation parameters...
February 23, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30771235/comparison-of-the-fragmentation-behavior-of-dna-and-lna-single-strands-and-duplexes
#18
Stefanie Ickert, Timm Schwaar, Andreas Springer, Márkó Grabarics, Jens Riedel, Sebastian Beck, Kevin Pagel, Michael W Linscheid
DNA and locked nucleic acid (LNA) were characterized as single strands, as well as double stranded DNA-DNA duplexes and DNA-LNA hybrids using tandem mass spectrometry with collision-induced dissociation. Additionally, ion mobility spectrometry was carried out on selected species. Oligonucleotide duplexes of different sequences - bearing mismatch positions and abasic sites of complementary DNA 15-mers - were investigated to unravel general trends in their stability in the gas phase. Single stranded LNA oligonucleotides were also investigated with respect to their gas phase behavior and fragmentation upon collision-induced dissociation...
February 16, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30769378/reactivity-of-4-thiothymidine-with-fenton-s-reagent-investigated-by-uv-visible-spectroscopy-and-electrospray-ionization-mass-spectrometry
#19
Vito Rizzi, Pinalysa Cosma, Ramona Abbattista, Paola Fini, Angela Agostiano, Tommaso R I Cataldi, Ilario Losito
The reactivity of the sulfur-containing nucleoside 4-thio-(2'-deoxy)-thymidine (S4 -TdR) under Fenton conditions, i.e. in the presence of H2 O2 and catalytic amounts of Fe (II), was investigated by UV-Vis spectroscopy and ElectroSpray Ionization Single and Tandem Mass Spectrometry (ESI-MS and MS/MS). S4 -TdR hydroxylated on the S atom was found to be a key reaction intermediate, ultimately leading to (2'-deoxy)-thymidine (TdR) as the main reaction product. This finding was in accordance with the outcome of the reaction between S4 -TdR and H2 O2 , previously investigated in our laboratory...
February 15, 2019: Journal of Mass Spectrometry: JMS
https://read.qxmd.com/read/30742348/fabrication-of-homogenous-three-dimensional-biomimetic-tissue-for-mass-spectrometry-imaging
#20
Xiaowei Song, Jiuming He, Chao Li, Chenglong Sun, Xuechao Pang, Jin Zhang, Qingce Zang, Zhigang Luo, Xin Li, Ruiping Zhang, Zeper Abliz
Reference samples are essential for mass spectrometric method optimization, data quality control, and target analyte quantitation. However, it is highly challenging to prepare an ideal homogeneous, standard-spiked tissue sample for mass spectrometry imaging (MSI) research. Herein, we present a standard-spiked 3D biomimetic tissue model fabricated with native cells, homogenate matrix, and biocompatible polymer. Unlike traditional homogenized tissue surrogates or those constructed with "on-tissue" or "under-tissue" micropipetting strategies, this simulated tissue shares both structural integrity of cells and homogeneous properties of matrix...
February 11, 2019: Journal of Mass Spectrometry: JMS
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