Fragment Ions of Dimethylsilane Produced by Hot Tungsten Wires

The scattering of the hydrocarbon radical cation C2D4•+ from room-temperature carbon (highly oriented pyrolytic graphite, HOPG) surface was investigated at low incident energies of 6-12 eV. Mass spectra, angular and translational energy distributions of product ions were measured. From these data, information on processes at surfaces, absolute ion survival probability, and kinematics of the collision was obtained. The projectile ion showed both inelastic, dissociative and reactive scattering, namely the occurrence of H-atom transfer reaction with hydrocarbons present on the room-temperature carbon surface. The absolute survival probability of the ions for the incident angle of 30° (with respect to the surface) decreased from about 1.0% (16 eV) towards zero at incident energies below 10 eV. Estimation of the effective surface mass involved in the collision process led to m(S)eff of about 57 a.m.u. for inelastic non-dissociative collisions of C2D4•+ and of about 115 a.m.u. for fragment ions (C2D3+, C2D2•+) and ions formed in reactive surface collisions (C2D4H+, C2D2H+, contributions to C2D3+ and C2D2•+). This suggested a rather complex interaction between the projectile ion and the hydrocarbon-covered surface during the collision.

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Comparison of isomeric C3H7O+ ion mobilities using fragment ions from 2-butanol and tert-butanol in He and Ne

Chemical Physics Letters ◽

10.1016/j.cplett.2019.137045 ◽

2020 ◽

Vol 739 ◽

pp. 137045

Author(s):

Kazunari Takaya ◽

Yuya Hasegawa ◽

Tetsuo Koizumi

Keyword(s):

Tert Butanol ◽

Fragment Ions

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Electron-impact dissociation ofCD3+andCH3+ions producingCD2+,CH+, andC+fragment ions

Physical Review A ◽

10.1103/physreva.79.052703 ◽

2009 ◽

Vol 79 (5) ◽

Cited By ~ 3

Author(s):

E. M. Bahati ◽

M. Fogle ◽

C. R. Vane ◽

M. E. Bannister ◽

R. D. Thomas ◽

...

Keyword(s):

Electron Impact ◽

Electron Impact Dissociation ◽

Fragment Ions

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Metastable fragment ions in multi-photon time-of-flight mass spectrometry: Decay channels of the benzene cation

International Journal of Mass Spectrometry and Ion Physics ◽

10.1016/0020-7381(83)85011-6 ◽

1983 ◽

Vol 51 (2-3) ◽

pp. 255-265 ◽

Cited By ~ 48

Author(s):

H. Kühlewind ◽

H.J. Neusser ◽

E.W. Schlag

Keyword(s):

Mass Spectrometry ◽

Time Of Flight ◽

Decay Channels ◽

Flight Mass Spectrometry ◽

Fragment Ions

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Chimera Spectrum Diagnostics for Peptides Using Two-Dimensional Partial Covariance Mass Spectrometry

Molecules ◽

10.3390/molecules26123728 ◽

2021 ◽

Vol 26 (12) ◽

pp. 3728

Author(s):

Taran Driver ◽

Nikhil Bachhawat ◽

Leszek J. Frasinski ◽

Jonathan P. Marangos ◽

Vitali Averbukh ◽

...

Keyword(s):

Mass Spectrometry ◽

Peptide Sequence ◽

Two Dimensional ◽

Peptide Ions ◽

Finite Mass ◽

Protein Database ◽

Spectra Analysis ◽

Fragment Ions ◽

Single Precursor ◽

The Common

The rate of successful identification of peptide sequences by tandem mass spectrometry (MS/MS) is adversely affected by the common occurrence of co-isolation and co-fragmentation of two or more isobaric or isomeric parent ions. This results in so-called `chimera spectra’, which feature peaks of the fragment ions from more than a single precursor ion. The totality of the fragment ion peaks in chimera spectra cannot be assigned to a single peptide sequence, which contradicts a fundamental assumption of the standard automated MS/MS spectra analysis tools, such as protein database search engines. This calls for a diagnostic method able to identify chimera spectra to single out the cases where this assumption is not valid. Here, we demonstrate that, within the recently developed two-dimensional partial covariance mass spectrometry (2D-PC-MS), it is possible to reliably identify chimera spectra directly from the two-dimensional fragment ion spectrum, irrespective of whether the co-isolated peptide ions are isobaric up to a finite mass accuracy or isomeric. We introduce ‘3-57 chimera tag’ technique for chimera spectrum diagnostics based on 2D-PC-MS and perform numerical simulations to examine its efficiency. We experimentally demonstrate the detection of a mixture of two isomeric parent ions, even under conditions when one isomeric peptide is at one five-hundredth of the molar concentration of the second isomer.

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Reaktive E=C(p–p)π Systeme, XXXIV Addition von Alkoholen oder primären Aminen an Phosphaalkene F3CP=C(F)OR. Neue Trifluormethylphosphane und -phosphaalkene/Reactive E = C( p – p ) π-Systems, XXXIV Addition of Alcohols or Primary Amines to Phosphaalkenes F3CP= C(F)OR . Novel Trifluoromethylphosphanes and Phosphaalkenes

Zeitschrift für Naturforschung B ◽

10.1515/znb-1993-0114 ◽

1993 ◽

Vol 48 (1) ◽

pp. 58-67 ◽

Cited By ~ 10

Author(s):

Joseph Grobe ◽

Duc Le Van ◽

Gudrun Lange

Keyword(s):

High Resolution Mass Spectrometry ◽

Molar Ratio ◽

Primary Amines ◽

The Novel ◽

Experimental Conditions ◽

Pull System ◽

Fragment Ions ◽

New Compounds ◽

C Nmr

The course of the reactions o f fluorophosphaalkenes F3CP = C (F)OR [R = Me (1), Et (2)] with methanol or ethanol strongly depends on the experimental conditions. Thus at 70 °C a mixture of the 2-phosphapropionic acid ester F3CP (H )CO2R [R = Me (3), Et (4)] and trifluoromethylphosphane H2PCF3 is formed [molar ratio: 3 or 4 /H2 CF3 ≈1/1]. If the precursors F3CP (H )CO2R [R = Me (3), Et) are used as starting materials, the reaction with ROH under the same conditions affords 3 and 4, respectively, (90 to 95% yield) with only traces of H2PCF 3. In the presence o f iPr2NH these precursors react with R′OH to give the novel trifluoromethylphosphaalkenes F3CP = C (OR )OR [R /R′: Me/Me (6); E t/E t (7); Me/Et (8)]. With Et2NH , 3 undergoes an addition/elimination process yielding the interesting push/pull system Et2N(F)C = P-CO2Me (5). 1 and 2 react with primary amines R′NH2 (R′= tBu, Me) with stereoselective formation of the fairly labile phosphaalkenes F3CP = C(OR)NHR′ [R /R′: Me/tBu (9), Et/tBu(10), Me/Me (11)] with trans-positions for CF3 and NHR′.The new compounds 3 -11 were characterized by spectroscopic investigations (1H , 19F, 31P, 13C NMR ; IR, MS) and determination of M+ or typical fragment ions [M+ -OR ] by high resolution mass spectrometry.

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Thermochemistry of Organic and Heteroorganic Species. Part IX. Photoionization Studies of Isomerization and Fragmentation of Polysubstituted Cyclopropenes: Phenyl-Substituted Cyclopropenes

European Journal of Mass Spectrometry ◽

10.1255/ejms.330 ◽

2000 ◽

Vol 6 (1) ◽

pp. 53-64 ◽

Cited By ~ 6

Author(s):

V.V. Takhistov ◽

I.N. Domnin ◽

D.A. Ponomarev

Keyword(s):

Mass Spectrometry ◽

Enthalpy Of Formation ◽

Good Alternative ◽

Enthalpies Of Formation ◽

Isodesmic Reactions ◽

Ion Structure ◽

Photoionization Mass Spectrometry ◽

General Methodology ◽

Fragment Ions ◽

The Enthalpy Of Formation

Ionization and appearance energies of some fragment ions from 1,2,3-trimethy1-3-phenyl-, 3-methyl-1,2,3-triphenyl-, 1,2-diphenyl-3-methoxycarbonyl-, 1,2,3-triphenyl-3-methoxycarbonyl- and 1,3,3-triphenyl-2-methoxycarbonyl-cyclopropenes were measured by photoionization mass spectrometry. It was shown that in none of these compounds did the fragment ions possess the expected stable substituted cyclopropenium ion structure. Accordingly, possible schemes of molecular ion isomerization are given. The enthalpies of formation of nearly 50 substituted cyclopropenium ions, and ions of related structure, were estimated using series of isodesmic reactions. This publication, together with the previous works of the authors in this Journal, demonstrates the general methodology for estimation of the enthalpy of formation for even-electron ions. It is suggested that the present methodology can provide a good alternative to other estimation or computation procedures applied to the thermochemistry of ions.

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Multistage Fragmentation of Ion Trap Mass Spectrometry System and Pseudo-MS3of Triple Quadrupole Mass Spectrometry Characterize Certain (E)-3-(Dimethylamino)-1-arylprop-2-en-1-ones: A Comparative Study

The Scientific World JOURNAL ◽

10.1155/2014/702819 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

Ali S. Abdelhameed ◽

Adnan A. Kadi ◽

Hatem A. Abdel-Aziz ◽

Rihab F. Angawi ◽

Mohamed W. Attwa ◽

...

Keyword(s):

Mass Spectrometry ◽

Mass Spectrometer ◽

Ion Trap ◽

Quadrupole Mass Spectrometer ◽

Ion Trap Mass Spectrometry ◽

Triple Quadrupole ◽

Quadrupole Mass ◽

Triple Quadrupole Mass Spectrometer ◽

Fragment Ions ◽

Mass Spectrometry System

A new approach was recently introduced to improve the structure elucidation power of tandem mass spectrometry simulating the MS3of ion trap mass spectrometry system overcoming the different drawbacks of the latter. The fact that collision induced dissociation in the triple quadrupole mass spectrometer system provides richer fragment ions compared to those achieved in the ion trap mass spectrometer system utilizing resonance excitation. Moreover, extracting comprehensive spectra in the ion trap needs multistage fragmentation, whereas similar fragment ions may be acquired from one stage product ion scan using the triple quadrupole mass spectrometer. The new strategy was proven to enhance the qualitative performance of tandem mass spectrometry for structural elucidation of different chemical entities. In the current study we are endeavoring to prove our hypothesis of the efficiency of the new pseudo-MS3technique via its comparison with the MS3mode of ion trap mass spectrometry system. Ten pharmacologically and synthetically important (E)-3-(dimethylamino)-1-arylprop-2-en-1-ones (enaminones4a–j) were chosen as model compounds for this study. This strategy permitted rigorous identification of all fragment ions using triple quadrupole mass spectrometer with sufficient specificity. It can be used to elucidate structures of different unknown components. The data presented in this paper provide clear evidence that our new pseudo-MS3may simulate the MS3of ion trap spectrometry system.

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