scholarly journals Contributions to the Interpretation of Mass Spectrum of Octaethoxycyclotetrasiloxane: Linked Scansand Isotopic Effects

Proceedings ◽  
2019 ◽  
Vol 29 (1) ◽  
pp. 103
Author(s):  
Virgil Badescu
Keyword(s):  
Mass Spectrum ◽  
Mass Spectrometer ◽  
Ionization Chamber ◽  
Electronic Impact ◽  
Fragmentation Reactions ◽  
Double Focusing ◽  
Isotopic Effects

The aim of this article is the study of the fragmentation reactions of octaethoxycyclotetrasiloxane (CTET) initiated by electronic impact in the ionization chamber of a double focusing mass spectrometer. [...]

scholarly journals Contributions to the Interpretation of Mass Spectrum of Hexaethoxydisiloxane Linked scans and M+1, M+2 isotopic effects

2019 ◽  
Vol 70 (8) ◽  
pp. 2934-2939
Author(s):  
Virgil Badescu
Keyword(s):  
Mass Spectrum ◽  
Ionization Chamber ◽  
Quantum Calculations ◽  
Electronic Impact ◽  
Primary Fragmentation ◽  
Fragmentation Reactions ◽  
The Masses ◽  
Double Focusing ◽  
Primary Ions ◽  
Isotopic Effects

The aim of this article is the study of the fragmentation reactions of hexaethoxydisiloxane initiated by electronic impact in the ionization chamber of a double focusing mass spectrometer. The initiation center of fragmentation reactions is established by quantum calculations. The daughter ions of hexaethoxydisiloxane molecular ion are obtained by linked scan B/E. The primary fragmentation ions with the masses 341, 297, 296 and 269 were obtained experimentally by B/E linked scan by radical induced fragmentation reactions. The eliminations of neutral fragments such as hydrogen, acetaldehyde, ethylene and water from the primary ions and the obtained ions by consecutive elimination reactions were emphasized experimentally by the B/E(1-E)1/2 linked scan by charge induced reactions.

scholarly journals Contributions to the Interpretation of Mass Spectra of the TEOS Methoxy-Transesters. Linked Scans, Accurate Mass Measurements and M+1, M+2 Isotopic Effects

2020 ◽  
Vol 71 (8) ◽  
pp. 39-54
Author(s):  
Virgil Badescu
Keyword(s):  
Mass Spectra ◽  
Structural Formula ◽  
Molecular Ions ◽  
Accurate Mass ◽  
Mass Measurements ◽  
Electronic Impact ◽  
Accurate Mass Measurements ◽  
Fragmentation Reactions ◽  
Double Focusing ◽  
Isotopic Effects

The aim of this article is the study of the fragmentation reactions of the methoxy-transesters of tetraethoxysilane (TEOS), with structural formula (CH3O)x(C2H5O)ySi, initiated by electronic impact in the ionization chamber of a double focusing mass spectrometer. The initiation centers of fragmentation reactions for the neutral and ionized TEOS methoxy-transesters were established by quantum calculations of net atomic charges. The ions of the mass spectra of the TEOS methoxy-transesters were obtained experimentally by the B/E and B/E(1-E)1/2 linked scans. Thus, there can be written the fragmentation pathways for the primary events by B/E linked scan (cleavage of methoxy and ethoxy groups) and eliminations of neutral molecules (acetaldehyde, ethylene, formaldehyde, molecular hydrogen) by B/E(1-E)1/2 linked scan. Accurate mass measurements at high resolution (5000), double bond equivalent (DBE) for the molecular ions and fragmentation ions of the TEOS methoxy-transesters and M+1, M+2 isotopic effects were used to confirm their identification. The reaction pathways and accurate mass in mass spectrum of dimethoxydiethoxysilane (TR2M) are detailed.

Contributions to the Interpretation of Mass Spectrum of Tetraethoxysilane (TEOS). III. Accurate mass and M+1, M+2 isotopic effect measurements

2020 ◽  
Vol 71 (2) ◽  
pp. 209-217
Author(s):  
Virgil Badescu
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrum ◽  
High Resolution ◽  
Sol Gel ◽  
Isotopic Effect ◽  
Sol Gel Process ◽  
Primary Fragmentation ◽  
Fragmentation Reactions ◽  
Primary Ions ◽  
Isotopic Effects

The aim of this article in continuation of Parts I [1] and II [2] is the interpretation of the TEOS mass spectrum as a precursor in the sol-gel process. In Part I [1] the primary fragmentation ions at masses 207, 193, 179 and 163 were obtained experimentally by B/E linked scan by radical induced fragmentation reactions. In Part II [2] eliminations of neutral fragments from the primary ions and the obtained ions by consecutive elimination reactions were evidenced experimentally by the B/E and B/E(1-E)1/2 linked scans. In this third and final Part of interpretation of the TEOS mass spectrum, the separation of ions by mass spectrometry at high resolutions of 5000 and 6600, relative to standard resolution 1000, and measurements of the M+1 and M+2 isotopic effects at the resolution of 5000 are presented. The separation of the ions with nominal mass 105 at high resolution is detailed.

The mass spectra of the Schiff base derived from ethylenediamine and trifluoroacetylacetone and its metal complexes

1975 ◽  
Vol 28 (7) ◽  
pp. 1517 ◽  
Author(s):  
SE Livingstone ◽  
JH Mayfield
Keyword(s):  
Schiff Base ◽  
Mass Spectrum ◽  
Metal Complexes ◽  
Mass Spectrometer ◽  
Mass Spectra ◽  
Fragmentation Reactions

The mass spectrum of the Schiff base formed by the condensation of ethylenediamine and trifluoro-acetylacetone shows that the compound is N,N-ethylenebis(1,1,1-trifluoro-4-iminopentan-2-one). The mass spectra of the nickel(II), palladium(II) and copper(II) chelates of the Schiff base confirm this structure for the ligand. Mechanisms are proposed for some of the fragmentation reactions which occur in the mass spectrometer.

scholarly journals Interaction of Fullerenes with Organosilanes in the Ionization Chamber of a Mass Spectrometer under Electron Impact and the Reaction of C60with Tetraphenylsilane in Solution under UV Irradiation

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Yury I. Lyakhovetsky ◽  
Elena A. Shilova ◽  
Alexandra P. Pleshkova ◽  
Alexander I. Belokon ◽  
Sergey O. Yakushin ◽  
...  
Keyword(s):  
Electron Impact ◽  
Mass Spectrometer ◽  
Uv Irradiation ◽  
Ionization Chamber ◽  
Ion Source ◽  
Organic Radicals ◽  
Mechanistic Study ◽  
Mass Spectral ◽  
Additional Support ◽  
Derivatives Of

C60was shown to react with organosilanes Me4Si, Ph2SiH2, Ph2MeSiH, Ph4Si, andα-naphthylphenylmethylsilane in the electron ionization ion source of a mass spectrometer with the transfer of the corresponding organic radicals (Me, Ph, andα-naphthyl) from the silanes to the fullerene. The reactions were accompanied by hydrogen addition to some products and hydrogen loss from them. C70reacted with Me4Si analogously. A reaction mechanism involving homolytic dissociation of the silanes under electron impact to the corresponding organic radicals, which react further with C60at the surface of the ionization chamber of the mass spectrometer to give the respective adducts, was offered. A mechanistic study of the reaction of C60with Me4Si supported it. No silicon containing derivatives of the fullerenes were found. C60reacted with Ph4Si in solution under UV irradiation in a similar fashion furnishing phenyl derivatives of the fullerene. These results provide an additional support to the hypothesis formulated earlier thatthe homolytic reactive mass spectrometry of fullerenes (the reactions of fullerenes with other species in the ionization chambers of mass spectrometers and their mass spectral monitoring)can predict the reactivity of them toward the same reagents in solution to a significant extent.

A novel double-focusing time-of-flight mass spectrometer for absolute recoil ion cross sections measurements

2016 ◽  
Vol 87 (8) ◽  
pp. 083112 ◽  
Author(s):  
L. Sigaud ◽  
V. L. B. de Jesus ◽  
Natalia Ferreira ◽  
E. C. Montenegro
Keyword(s):  
Mass Spectrometer ◽  
Cross Sections ◽  
Time Of Flight ◽  
Flight Mass Spectrometer ◽  
Double Focusing

scholarly journals A comparison between the two lobes of comet 67P/Churyumov–Gerasimenko based on D/H ratios in H2O measured with the Rosetta/ROSINA DFMS

2019 ◽  
Vol 489 (4) ◽  
pp. 4734-4740 ◽  
Author(s):  
Isaac R H G Schroeder ◽  
Kathrin Altwegg ◽  
Hans Balsiger ◽  
Jean-Jacques Berthelier ◽  
Michael R Combi ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
European Space Agency ◽  
Cometary Nucleus ◽  
The Other ◽  
Appreciable Difference ◽  
Space Agency ◽  
Close Proximity ◽  
Double Focusing ◽  
Comet 67P

ABSTRACT The nucleus of the Jupiter-family comet 67P/Churyumov–Gerasimenko was discovered to be bi-lobate in shape when the European Space Agency spacecraft Rosetta first approached it in 2014 July. The bi-lobate structure of the cometary nucleus has led to much discussion regarding the possible manner of its formation and on how the composition of each lobe might compare with that of the other. During its two-year-long mission from 2014 to 2016, Rosetta remained in close proximity to 67P/Churyumov–Gerasimenko, studying its coma and nucleus in situ. Based on lobe-specific measurements of HDO and H2O performed with the ROSINA Double Focusing Mass Spectrometer (DFMS) on board Rosetta, the deuterium-to-hydrogen (D/H) ratios in water from the two lobes can be compared. No appreciable difference was observed, suggesting that both lobes formed in the same region and are homogeneous in their D/H ratios.

Sign in / Sign up

Export Citation Format

Share Document