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Volume 57 (2009)
- Issue 6 Pages 371-
- Issue 5 Pages 331-
- Issue 4 Pages 241-
- Issue 3 Pages 117-
- Issue 2 Pages 45-
- Issue 1 Pages 1-
Volume 57, Issue 5
Displaying 1-4 of 4 articles from this issue
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REGULAR PAPER
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Motohiro SHIZUMA, Hirofumi SATO, Yoshio TAKAI, Daisuke ONO, Takeyuki S ...2009 Volume 57 Issue 5 Pages 331-339
Published: October 01, 2009
Released on J-STAGE: October 19, 2009
JOURNAL FREE ACCESSChiral discrimination by novel chiral hosts 3 and 4, which consist of an oxyethylene chain and 2,3:5,6-di-O-cyclohexylidene-β-D-mannofuranose moieties at both ends, was examined considering several protonated amino acid isopropyl ester guests using fast atom bombardment mass spectrometry (FABMS) with the enantiomer deuterium-labeled guest method. Host 3 showed chiral discrimination toward several guests but with slightly smaller chiral discrimination abilities than host 2a, which consists of a bis-(oxyethylene) chain and 1,2:3,4-di-O-isopropylidene-α-D-galactopyranoside moieties at both ends. Host 4 showed no enantioselectivity, possibly because chiral hosts do not show a pseudo-ring conformation having large open spaces in complexations with a chiral guest in regard to the steric effects of cyclohexylidene groups. In addition, to understand the chiral recognition mechanisms, the binding sites of hosts 3 and 4 were elucidated by ultraviolet-visible (UV-VIS) and proton nuclear magnetic resonance (1H-NMR) spectroscopy.View full abstractDownload PDF (734K)
NOTE
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Takahiro TORII, Hae-Yang PAK, Kozo MATSUMOTO, Kuniyuki KITAGAWA2009 Volume 57 Issue 5 Pages 341-343
Published: October 01, 2009
Released on J-STAGE: October 19, 2009
JOURNAL FREE ACCESSIdentification of intermediate chemical species in a combustion flame is an important step for obtaining energy with high efficiency from combustion, reducing the toxic emissions released by combustion, and understanding reaction mechanisms in flames. We have developed a unique system based on ion attachment mass spectrometry (IAMS) to identify such intermediates. In this system, the chemical species generated in flames under atmospheric pressure are directly introduced through a sampling cone of a newly developed interface into the ionization chamber (ca. 2 Pa). Then, the species are ionized by Li+ ion attachment and introduced into a quadrupole mass spectrometer operating at ca. 1×10-3 Pa. Intermediate species in flames were successfully detected. Notably, the production of highly toxic environmental pollutants, such as formaldehyde (HCHO) and acetaldehyde (CH3CHO), were confirmed to be produced during combustion of the promising alternative fuels, dimethyl ether (CH3OCH3) and ethanol (CH3CH2OH). In addition, by moving the burner position for detecting the species at various positions, the abundance of the species in the flames was observed in two-dimensional distribution profiles. Some correlations were found between the distributions of intermediate species and the flame temperature.View full abstractDownload PDF (113K)
REVIEW
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—Basic Explanation for Collisions in Mass Spectrometry—Shigeo HAYAKAWA2009 Volume 57 Issue 5 Pages 345-362
Published: October 01, 2009
Released on J-STAGE: October 19, 2009
JOURNAL FREE ACCESSRecent development in mass spectrometry has far-reaching effects not only in physical and chemical studies of gaseous molecules and ions, but also in biological studies, including proteomics and metabolomics. In mass spectrometry, collisions are very important elementary processes in ionization, collision-induced dissociation, and mobility, whose methods are useful for the development of proteomics and metabolomics. In the present review, to understand the basis of collision, the concepts of center-of-mass system, laboratory system, cross section, kinetic energy release, and impact parameter are explained. The cross sections, which provide the magnitude of elementary reactions, depend on reaction species, collision energies, and reaction processes. I have attempted to present these dependences with the support of various examples.View full abstractDownload PDF (2989K)
INTEGRATED PAPER
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Takaya SATOH2009 Volume 57 Issue 5 Pages 363-369
Published: October 01, 2009
Released on J-STAGE: October 19, 2009
JOURNAL FREE ACCESSA novel time-of-flight mass spectrometer that utilizes a spiral ion trajectory was developed. In this mass spectrometer, the ions sequentially pass through four toroidal electrostatic sectors and revolve along a figure-eight-shaped orbit on a particular projection plane. Each toroidal electrostatic sector has eight stories, and during multiple revolutions, the ion trajectory shifted perpendicular to the projection plane in every cycle, thereby generating a spiral trajectory. Two prototypes, orthogonal acceleration time-of-flight mass spectrometer (OA-TOFMS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOFMS) were made and tested. The total flight path lengths were 20 and 17 m for OA-TOFMS and MALDI-TOFMS, respectively. By adopting an ion optical system that has a flight path length more than five times longer than that of the commonly used reflectron ion optical system, the m/z-dependent mass resolving power was reduced while improving the mass accuracy of the mass measurements.View full abstractDownload PDF (1301K)
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