Collisionally-activated dissociation of methane molecular ion. Analysis of a mass-analysed ion kinetic energy peak shape

1990 ◽  
Vol 4 (9) ◽  
pp. 327-334 ◽  
Author(s):  
Byung Joo Kim ◽  
Myung Soo Kim
Keyword(s):  
Kinetic Energy ◽  
Peak Shape ◽  
Molecular Ion ◽  
Collisionally Activated Dissociation ◽  
Energy Peak ◽  
Ion Kinetic Energy ◽  
Ion Analysis

Rearrangements in the Molecular Ions of Some ortho-Substituted Schiff Bases

1993 ◽  
Vol 46 (6) ◽  
pp. 895 ◽  
Author(s):  
T Blumenthal ◽  
M Dosen ◽  
RG Gillis ◽  
QN Porter
Keyword(s):  
Kinetic Energy ◽  
Schiff Bases ◽  
Molecular Ions ◽  
Energy Spectra ◽  
Supporting Evidence ◽  
Deuterium Labelling ◽  
Methyl Group ◽  
Molecular Ion ◽  
Fragment Ions ◽  
Ion Kinetic Energy

Under electron ionization conditions, the ortho-substituted Schiff bases N-benzylidene-o-toluidine (1a), N-(o-methylbenzylidene)aniline (1b), N-salicylideneaniline (1c) and N-(o-methoxybenzylidene)aniline (1d) give fragment ions which have been shown by collision-activated mass-analysed ion kinetic energy spectra to have the structure of the protonated molecular ions of indole (2), benzofuran (3), and 1,2-benzisoxazole (4). The molecular ion of N-(o-methylbenzylidene)-o-toluidine (1f) gives as fragment ions not only the protonated molecular ion (2) of indole and the tropylium ion but also the molecular ion of anthracene. Attempts to find supporting evidence for a mechanism for this rearrangement by deuterium labelling of a methyl group in (1b), such as (1g), have been unsuccessful.

The Electron Impact Induced Fragmentation of 1-Aryl-5-hydroxy-1,2,3-triazole-4-carboxamides

1990 ◽  
Vol 43 (12) ◽  
pp. 2021 ◽  
Author(s):  
AT Lebedev ◽  
TY Samguina ◽  
T Blumenthal ◽  
MY Kolobov
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Kinetic Energy ◽  
Electron Impact ◽  
High Resolution Mass Spectrometry ◽  
Energy Spectra ◽  
Molecular Ion ◽  
High Resolution Mass ◽  
Ion Kinetic Energy ◽  
Resolution Mass

The pathways of the electron impact induced fragmentation of 1-aryl-5- hydroxy-1,2,3-triazole-4-carboxamides were studied. The compositions of the key ions were confirmed by high-resolution mass spectrometry. The proposed pathways were established from mass analysed ion kinetic energy spectra, and B/E and B2/E linked scans. A variety of structures for the molecular ion of the title compounds is proposed.

Ion Kinetic Energy Determinations in Radio-Frequency Glow Discharge Mass Spectrometry

1995 ◽  
Vol 49 (7) ◽  
pp. 917-926 ◽  
Author(s):  
Paula R. Cable ◽  
R. Kenneth Marcus
Keyword(s):  
Kinetic Energy ◽  
Glow Discharge ◽  
Radio Frequency ◽  
Source Region ◽  
Potential Method ◽  
Operating Conditions ◽  
Atmospheric Plasma ◽  
Radio Frequency Glow Discharge ◽  
Ion Trajectory ◽  
Ion Kinetic Energy

Radio-frequency glow discharge (rf-GD) sources produce an abundance of both atoms and ions. For the mass spectrometric application of the glow discharge technique, knowledge of the ion kinetic energies is required to optimize extraction and focusing of ions from the source region into the analyzer. This paper details kinetic energies experimentally determined with the use of the “retarding potential” method. For this study, the analyzer quadrupole of a double-quadrupole mass spectrometer was positively biased to act as a repeller. Ion kinetic energies (IKEs) determined for a variety of discharge and analyzer operating conditions ranged from 12.5 eV to 25.0 eV for 63Cu+. Kinetic energy measurements were confirmed from ion trajectory simulations and follow closely the experimental values for identical analyzer conditions and initial IKEs. Results of this study indicate that the conditions under which ions are formed (plasma conditions) affect IKEs and energy spreads to a greater extent than analyzer parameter variations. Different from atmospheric plasma sources, IKEs for rf-GD species do not vary as a function of ion mass/identity. Evidence is also given in support of a slight mass biasing owing to the transmission properties of double-quadrupole analyzers. The findings detailed herein demonstrate the effects of rf modulation on both ion kinetic energy values and distributions.

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