Journal of the Mass Spectrometry Society of Japan
Online ISSN : 1880-4225
Print ISSN : 1340-8097
ISSN-L : 1340-8097
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Volume 38, Issue 1
Displaying 1-5 of 5 articles from this issue
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REGULAR PAPERS
  • Influence of Magnetic Saturation in Inhomogeneous Magnetic Field
    Hisashi Matsuda
    1990 Volume 38 Issue 1 Pages 1-5
    Published: 1990
    Released on J-STAGE: May 01, 2007
    DOIhttps://doi.org/10.5702/massspec.38.1
    JOURNAL FREE ACCESS
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    The field distribution of an inhomogeneous magnetic field in the conical pole gap is calculated considering the influence of magnetic saturation of pole material. Magnetic fields corresponding to the ideal n-values of -1.5 and -2 are calculated for various different field strengths. The results show that the distortion due to the magnetic saturation is very serious in the strong magnetic field above 15 kG for pure iron and above 20 kG for vanadium permendur. The variations of n1 and n2 with increasing B are also shown.
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  • EI Mass Spectra of 7-Azabenzonorbornadienes
    Mamoru Ohashi, Takeshi Tani, Shuzo Yamada
    1990 Volume 38 Issue 1 Pages 7-12
    Published: 1990
    Released on J-STAGE: May 01, 2007
    DOIhttps://doi.org/10.5702/massspec.38.7
    JOURNAL FREE ACCESS
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    The EI mass spectral fragmentation of four 7-azabenzonorbornadiene derivatives was investigated. Fragmentation processes are proposed on the basis of accurate mass measurements and B/E constant linked scannings. Three major fragmentation pathways, i.e., 1) retro-Diels-Alder reactions resulting in the loss of acetylene, 2) cheletropic reactions giving naphthalene derivatives, and 3) rearrangements to quadricyclene derivatives followed by ring cleavage giving N-alkyl nitrile cations, were deduced.
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  • Study on the Fragmentation Mechanism of 1-Substituted Cyclohexane-3,5-diones under Electron Ionization
    Yuji Ikenishi, Yuzo Nakagawa
    1990 Volume 38 Issue 1 Pages 13-23
    Published: 1990
    Released on J-STAGE: May 01, 2007
    DOIhttps://doi.org/10.5702/massspec.38.13
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    EI mass spectral fragmentation of 1-X-cyclohexane-3,5-diones (X=CH2, O, S) has been investigated by using MO calculation. It has been revealed that the first bond cleavage occurs at either 2-3 or 5-6 bond corresponding to α-cleavage with respect to carbonyl group and 1-X, followed by two competitive bond cleavage giving [M-CO]+· or [M-CH2X]+·, respectively.
    The potential energies of CO or CH2X elimination from the acyclic molecular ion have been determined by MNDO. In 1-oxa compounds, the CO elimination process is energetically more favorable than the CH2X elimination process, while the CH2X elimination process is more favorable in 1-thia compounds.
    This result is in good agreement with the relative intensities of fragment ions [M-CO]+· and [M-CH2X]+·.
    In addition to the above description, the effect of 1-X on ring-bond cleavage has been discussed.
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  • Mass Spectrometry of Furanoid Diterpene Glucosides Resisted to Hydrolysis
    Michiko Yonemitsu, Naomichi Fukuda, Takeatsu Kimura, Ryuichi Isobe, Te ...
    1990 Volume 38 Issue 1 Pages 25-34
    Published: 1990
    Released on J-STAGE: May 01, 2007
    DOIhttps://doi.org/10.5702/massspec.38.25
    JOURNAL FREE ACCESS
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    The comparative investigation into the mass spectrometric analysis of nine furanoid diterpene glucosides and their aglycones were made by the electron impact (EI), fast atom bombardment (FAB), and field desorption (FD) mass spectrometry (MS).
    The EI mass spectra provided the diagnostic informations concerning stereoisomerism of the aglycone parts. The FAB mass spectra could reveal the molecular ion peaks of the glucosides by both the positive and the negative ion modes, and the abundant knowledge on the structural features of those compounds could be obtained by the FDMS. Particularly, the ions at m/z 163 which indicated the sugar moieties were easily detected, even if their glucosidic bonds resisted to chemical and enzymatic hydrolysis.
    As a promising aid for obtaining structural information of minute amounts of furanoid diterpene glucosides and their aglycones, the utility of the combined use of the EI and the FDMS was emphasized.
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TECHNICAL REPORT
  • Mass Selective Excitation of Cyclotron Motion of Ions in Fourier Transform Ion Cyclotron Resonance (FT-ICR) Spectrometry
    Hisao Katakura, Masao Inoue
    1990 Volume 38 Issue 1 Pages 35-42
    Published: 1990
    Released on J-STAGE: May 01, 2007
    DOIhttps://doi.org/10.5702/massspec.38.35
    JOURNAL FREE ACCESS
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    Recent progress in electronics has made it possible for us to utilize commercial instruments in building an excitation and data sampling system for Fourier transform ion cyclotron resonance (FT-ICR) spectrometry.
    An arbitrary waveform generator was used to excite mass-selected ions trapped in an FT-ICR cell and a digital oscilloscope was used to sample and process signals of resonant ions. Excitation waveforms were synthesized from sinusoidal waves of specific frequencies to excite the ions of various mass-to-charge ratios. Simultaneous excitation/ejection experiment was performed by varying amplitude of each frequency component in the excitation waveform. The arbitrary waveform generator has been proved to be useful for SWIFT (stored waveform inverse Fourier transform) experiment as an interface between the computer and the FT-ICR spectrometer.
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