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 50, Issue 1
Displaying 1-7 of 7 articles from this issue
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REGULAR PAPERS
  • Monte Carlo Simulation for Pressurized Experimental Events in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry
    Yasuhide NAITO, Makoto FUJIWARA
    2002 Volume 50 Issue 1 Pages 1-6
    Published: 2002
    Released on J-STAGE: October 16, 2007
    DOIhttps://doi.org/10.5702/massspec.50.1
    JOURNAL FREE ACCESS
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    An ion trajectory simulation code based on a stochastic sampling method was developed for pressurized events in Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. The ion-neutral interaction was modeled by discrete collisions and was characterized by appropriate probability density functions. The use of randomization allows a more realistic representation of ion behaviors than a conventional approach, such as a viscous drag model. Besides, the proposed simulation can depict a time-varying internal energy, which may provide a useful measure for collisionally activated decomposition processes. The simulation code has been applied to various experimental situations of pressurized events; sustained off-resonance irradiation, quadrupolar excitation axialization and rf-only-mode trapping. The simulation results revealed the dynamics and the energetics of a trapped ion undergoing these pressurized events.
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  • A New Channel of Hydrogen Elimination in the 121.6-nm Photodissociation of Formic Acid Detected by a Doppler-Selected TOF Mass Spectrometry
    Michihiro HASHINOKUCHI, Ryoji KOUMURA, Dock-Chil CHE, Hiroshi OHOYAMA, ...
    2002 Volume 50 Issue 1 Pages 7-10
    Published: 2002
    Released on J-STAGE: October 16, 2007
    DOIhttps://doi.org/10.5702/massspec.50.7
    JOURNAL FREE ACCESS
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    Hydrogen-atom elimination channels in 121.6-nm photodissociation of formic acid were investigated by a Doppler-selected TOF mass spectrometry (DS-TOF-MS). This mass spectroscopic method enables us to map out three dimensional velocity distributions of photodissociated products through multiphoton ionization for the H atoms, and therefore we can determine anisotropic parameter β. The H+HCOO* channel is found to be a main branching among many H elimination channels. A new three-body channel of H+CO+OH is observed. We estimate that the H+HCOO* channel is more favor than the H+CO+OH channel by a factor of ~5. Other H-elimination channels such as H+HCOO, 2H+CO2, H+HOCO, and H+CO+OH(A) are found to be small. These results show that the DS-TOF-MS method is useful to determine branching ratios and internal energy distributions of photodissociated products in excited states as well as ground states in addition to anisotropic parameter determination.
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  • Simultaneous Measurement of Mass and Velocity Distributions of Cluster Beams by Orthogonal Acceleration Time-of-Flight Mass Spectrometers
    Naoaki SAITO, Kazuyoshi KOYAMA, Mitsumori TANIMOTO
    2002 Volume 50 Issue 1 Pages 11-14
    Published: 2002
    Released on J-STAGE: October 16, 2007
    DOIhttps://doi.org/10.5702/massspec.50.11
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    In order to study cluster beams, it is essential to measure their mass and velocity distributions as the fundamental characteristics. We demonstrate an experimental method to simultaneously measure both the mass spectrum and the beam velocities by the orthogonal acceleration time-of-flight mass spectrometer. The method is based on the ion-interruption effect of the electrode wire-mesh in the accelerator. The neutral clusters are photoionized in a small area in the accelerator, accelerated perpendicularly to the cluster beam axis, mass-analyzed and detected. Depending on the mass and the beam velocity, specific ions are interrupted by the wires arranged with a equal spacing and can not reach the detector. This ion-interruption effect modulates the transmittance of the ions, yielding the apparent oscillations in the mass spectra. Unfolding these modulated mass spectra, we have successfully measured both the mass spectrum and the beam velocities as a function of the mass simultaneously.
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  • Application of TLC-MALDI-TOFMS to Identification of Co(II) and Co(III) Acetylacetonates
    Kozo MATSUMOTO, Hiroharu AJIRO, Shigeki HABAUE, Yoshio OKAMOTO
    2002 Volume 50 Issue 1 Pages 15-17
    Published: 2002
    Released on J-STAGE: October 16, 2007
    DOIhttps://doi.org/10.5702/massspec.50.15
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    The mass spectra of Co(II) acetylacetonate and Co(III) acetylacetonate were measured by MALDI-TOF-MS. Complex peaks, such as the adduct peaks and cluster peaks, were observed in their mass spectra. The two compounds had different mass spectra. The compounds could be identified by their mass spectra. TLC-MALDI-TOFMS was applied to a mixture of these compounds. The separated spots on the TLC plate gave similar mass spectra to that of the conventional MALDI-TOFMS, when a mixture of solvents with acetylacetone was used as the developing and eluting solvents.
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