All issues
Volume 41, Issue 1
Displaying 1-7 of 7 articles from this issue
- |<
- <
- 1
- >
- >|
INTEGRATED PAPER
-
Atsumu HIRABAYASHI1993 Volume 41 Issue 1 Pages 5-17
Published: 1993
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSAtmospheric pressure spray (APS) ionization can produce quasi-molecular ions of biological molecules from their aqueous solution, and has therefore been developed as an interface for LC/MS. In this article, we first outline models of the ion production mechanisms developed for spray ionization methods such as thermospray and electrospray. Then, the experimental results using APS are presented. We investigate whether the quasi-molecular ions are produced by ion-molecule reactions in the gas phase, by ion evaporation (in which ions are produced by the spray), or by both mechanisms. It is concluded that a volatile molecule such as ammonia is produced by the spray and protonated by an ion-molecule reaction in the gas phase. For nonvolatile molecules such as sucrose and amino acids, however, their quasi-molecular ions are produced partly by ion evaporation and partly by the gas phase reaction. It is also shown that the relative intensities of the protonated amino-acid molecules produced by ion evaporation are not necessarily determined by the equilibrium in the bulk liquid. A qualitative explanation is proposed on the basis of the Gibbs energy of hydration.View full abstractDownload PDF (980K)
REGULAR PAPERS
-
Hirohiko EZOE, Eiichiro GOTOH1993 Volume 41 Issue 1 Pages 19-24
Published: 1993
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSAttenuation of ion beam by ion-molecule collisions which occurred in a mass spectrometer were observed and total microscopic cross sections for He+-He, Ne+-Ne, Ar+-Ar, Ar2+-Ar, and N2+-N2 were evaluated at the ion acceleration voltages of 300, 500, and 1,000 volts. The accuracies of the present results seemed to depend almost upon those of the relative sensitivities of the ionization gauge employed.View full abstractDownload PDF (242K) -
Shozo TAMAKI, Naohiko YAMAUCHI, Tsukasa KURODA1993 Volume 41 Issue 1 Pages 25-35
Published: 1993
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSLow-alloy and stainless steels of known composition were Ar+-(or O2+-) bombarded, and the secondary ion currents were converted to elemental concentrations with a help of the Saha-Eggert equation. When the secondary ions are emitted from the surface layer which contains as many oxygen atoms as possible, the calculated concentrations were sufficiently close to the specified values for most constituent elements. This indicates that the secondary ion emission from the surface layer of steels can be simulated by the local thermodynamic equilibrium model when the layer contains many oxygen atoms.View full abstractDownload PDF (648K) -
Koichi OGURA, Takemasa SHIBATA1993 Volume 41 Issue 1 Pages 37-45
Published: 1993
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSSymmetric resonance charge transfer cross sections between singly ionized gadolinium ion and the parent atom were measured in the impact energy range of 100~1000 eV. The cross sections were determined from the ratio between the number of ions produced by charge transfer and those in primary ion beam. The primary ion beam of gadolinium was produced by a laser ion source in which gadolinium atoms were ionized by resonance photoionization. The slow ions produced by charge transfer and fast primary ions were detected with Faraday cups. The obtained cross section was about 1.5×10-14cm2 at impact energy of 500 eV. The dependence of the measured cross sections on the impact energy roughly agrees with theoretical prediction.View full abstractDownload PDF (523K) -
Hisao NAKATA, Kenji KADOGUCHI1993 Volume 41 Issue 1 Pages 47-50
Published: 1993
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSThe CH4-mediated chemical ionization mass spectrum was measured for a trisubstituted aromatic compound, 3-aminomethyl-5-methoxymethylbenzyl alcohol, 3-(NH2CH2)-5-(CH3OCH2)-C6H3-CH2OH. The observed spectral pattern was in good agreement with that predicted by our recently reported procedure, which based on protonation susceptibility and fragmentation capability of functional groups. The present results provide the rationale for our approach to the semi-quantitative analysis of the chemical ionization mass spectrum.View full abstractDownload PDF (247K) -
Hiroshi KISHI, Toshihiro FUJII1993 Volume 41 Issue 1 Pages 51-62
Published: 1993
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSThis paper describes an experimental study on the influence of the kinetic energy in surface ionization, using Ni and ReO2 surfaces and fast toluene and piperidine molecules. These accelerated molecules in seeded supersonic molecular beams expanded from a nozzle and were suddenly brought to interact with surfaces by collision.
Results were obtained as a function of incident kinetic energy and system parameters, indicating that kinetic energy causes the surface ionization to increase drastically above threshold energy. The threshold kinetic energy was 3.5 and 3.4 eV for toluene/Ni and piperidine/ReO2, respectively.View full abstractDownload PDF (739K) -
Masaharu TSUJI, Ken-ichi MATSUMURA, Tsuyoshi FUNATSU, Hiroyuki KOUNO, ...1993 Volume 41 Issue 1 Pages 63-72
Published: 1993
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSThermal energy ion-molecule reactions of Ar+ with n-C4H10 and iso-C4H10 have been studied by using a low-energy beam apparatus. The total reaction rate constants were determined to be (7.9±2.8) × 10-10 and (8.6±3.1) × 10-10cm3s-1 for n-C4H10 and iso-C4H10, respectively. These values amount to about 60% of calculated values from Langevin theory. Major exit channels observed were C2H5+ (36%), C2H3+ (32%), and C3H5+ (22%) for n-C4H10, while C2H3+ (46%) and C3H5+ (42%) for iso-C4H10. The product ion distributions suggested that charge transfer occurs through near-resonant electron jump. The dissociative ionization processes were discussed from photoelectron spectroscopic data.View full abstractDownload PDF (648K)
- |<
- <
- 1
- >
- >|