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 58, Issue 5
Displaying 1-4 of 4 articles from this issue
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  • Raman Spectroscopic Investigation of the Isotopic Effects in Graphitic Carbon and the Interpretation of D-Band
    Kazuhiko MORISHITA, Masayuki NARA, Jun-ichi MATSUDA
    2010 Volume 58 Issue 5 Pages 167-168
    Published: October 01, 2010
    Released on J-STAGE: October 16, 2010
    DOIhttps://doi.org/10.5702/massspec.58.167
    JOURNAL FREE ACCESS
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    The origin of D-band of graphite has not been well understood up to date. We have carried out the Raman microscopic study of pure 12C and 13C graphitic carbon. The peak positions of the individual Raman bands of 13C graphitic carbon downshift from those of 12C graphitic carbon, and the wave number ratios of 13C to 12C are equal to 0.96 for all kinds of Raman band positions. This value corresponds to the inverse of square root of the mass ratio of 13C and 12C, indicating that all of these Raman bands can be explained by the lattice vibrational mode in the monoatomic crystal model. The degree of downshift of Raman band positions could be a good indicator to estimate the carbon isotopic ratios in graphitic material.
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  • Influence of Ion-Ion Coulomb Interactions on FT-ICR Mass Spectra at a High Magnetic Field: A Many-Particle Simulation Using a Special-Purpose Computer
    Makoto FUJIWARA, Naohisa HAPPO, Koichi TANAKA
    2010 Volume 58 Issue 5 Pages 169-173
    Published: October 01, 2010
    Released on J-STAGE: October 16, 2010
    DOIhttps://doi.org/10.5702/massspec.58.169
    JOURNAL FREE ACCESS
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    A previously developed simulation program code for FT-ICR mass spectra has been improved and accelerated using a special-purpose computer for many-body problems. As a result, the simulation speed has become 10 times faster. Thus it has been possible to compute longer ICR transient signals and simulate the FT-ICR mass spectra with higher resolving power. The accelerated computing configuration was applied to simulation for the influence of ion-ion Coulomb interactions on FT-ICR mass spectra especially at a high magnetic field. At a magnetic field of 5 T, the peak coalescence problem was investigated and at high ion density the peak coalescence appeared for closely spaced m/z ion mixtures of m/z 100.00 and 100.05; however, the complete phase locking of the two ion clouds, which is expected to occur under the conditions at a low magnetic field and high ion density, was not observed. Furthermore, ion loss ratio was estimated for m/z 100.00 ions as a function of initial ion population and it was found that the peak intensity is proportional to the initially trapped ion population at low ion density; however, the linearity is not maintained at high ion density.
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REVIEW
  • Fundamentals of Mass Spectrometry
    —Secondary Ion Mass Spectrometry (SIMS), Cluster SIMS, and Electrospray Droplet Impact SIMS—
    Kenzo HIRAOKA
    2010 Volume 58 Issue 5 Pages 175-184
    Published: October 01, 2010
    Released on J-STAGE: October 16, 2010
    DOIhttps://doi.org/10.5702/massspec.58.175
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    The use of secondary ion mass spectrometry (SIMS) to characterize inorganic, organic and biological materials has undergone significant and multiple advances in the past thirty years. Additional development in cluster ion sources that started in the early 1990s laid the ground work for the significant increase in SIMS investigations in material science. The continuing scaling trend leads to a drastic reduction in film thicknesses which increases the demands for very high depth resolution, ideally a multilayer system with the depth resolution in the order of 0.5 nm. Recently, the electrospray droplet impact (EDI) has been developed that uses the atmospheric pressure electrospray as a cluster ion source. EDI/SIMS is very high-sensitive and EDI is capable of very shallow surface etching without the damage left on the etched surface. In this chapter, the fundamentals and applications of EDI to the surface analysis are dealt with.
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COMMENTARY
  • Probing the Structure and Function of Proteins by Mass Spectrometry
    —Structural Analysis of Prion Proteins by Ion Mobility Mass Spectrometry—
    Kazuo HIRAYAMA
    2010 Volume 58 Issue 5 Pages 185-194
    Published: October 01, 2010
    Released on J-STAGE: October 16, 2010
    DOIhttps://doi.org/10.5702/massspec.58.185
    JOURNAL FREE ACCESS
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    Applications of traveling-wave ion mobility (T-Wave-IM) and drift cell ion mobility (DCIM) mass spectrometry to studies of prion proteins are summarized. In ion mobility spectrometry, ions that are produced travel through a drift tube to which has an electric field is applied and a carrier buffer gas that opposes the motion of the ions. Based on the mass, charge, size and shape, and the migration time of an ion through the tube is unique to each different ion. This permits the operator to distinguish between different analyte species. Compact ions with small collision cross-sections will drift more rapidly than extended ions. The measurement of this mobility yields information regarding the rotationally-averaged cross-section of each ion. Separation of α-helical and β-sheet-rich SHaPrP(90-231) isoforms of recombinant Syrian hamster prion proteins, with the same m/z but different structures, can be achieved via the use of ion mobility data.
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