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Volume 39 (1991)
- Issue 6 Pages 301-
- Issue 5 Pages 213-
- Issue 4 Pages 183-
- Issue 2 Pages 49-
- Issue 1 Pages 1-
Volume 39, Issue 1
Displaying 1-6 of 6 articles from this issue
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REGULAR PAPERS
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Noriko TORIGOYE, Masako SHIMA1991 Volume 39 Issue 1 Pages 1-12
Published: 1991
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSIn this paper, the method for obtaining the internal Rb-Sr system of enstatite chondrite is presented. The mineral separation was carried out by stepwise dissolution combined with grain size separation. Such method as well as the stepwise dissolution using 1 M HF was applied to the age determination for the first time. The details of analytical procedures including chemistry and mass spectrometry are also described. The blank levels of Rb and Sr during mineral separations and chemical treatments are negligibly low.
The result of Rb-Sr data of Khairpur enstatite chondrite represents the performance of this method. The silicate phases separated by grain sizes and 1M HF dissolution showed the precise isochron. The statistical errors of the age and the initial 87Sr/86Sr ratio are as good as 1% and 0.05%, respectively. This is the clear evidence that the stepwise dissolution does not dissolve recoiled atoms by nuclear decay process, nor leach elements selectively between Rb and Sr, thus could be used on the internal Rb-Sr isochron studies, as a strong means.View full abstractDownload PDF (796K) -
Hisao NAKATA, Naozumi YAMAGUCHI, Akemi SAWADA, Yasuko TACHIKI, Hideyuk ...1991 Volume 39 Issue 1 Pages 13-18
Published: 1991
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSPositive ion chemical ionization mass spectra were measured for bifunctional compounds of the type p-XCH2-C6H4-CH2Y, where X=NH2 and NHCOCH3, and Y=OH and OCOCH3. The data can be analyzed in semi-quantitative manner in terms of protonation susceptibility and fragmentation capability of each functional groups. The abnormal behavior of N, O-diacetyl compound was explained by the intramolecular proton transfer between two carbonyl oxygen atoms in [MH]+.View full abstractDownload PDF (389K) -
Eiichi TABEI, Shigeru MORI, Fumio OKADA, Susumu TAJIMA, Seiji TOBITA1991 Volume 39 Issue 1 Pages 19-27
Published: 1991
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSThe unimolecular fragmentations of 1,1,1,3,3,3-hexamethyldisilazane (1), and 1,1,3,3-tetramethyldisilazane (2) were investigated by mass-analyzed ion kinetic energy (MIKE) spectra. D-Labelling studies and high resolution data were also included. One of the characteristic fragmentations of these compounds was the loss of CH4 after the expulsion of CH3 or H from the molecular ions.
In the case of 1, D-labelling study indicated that the hydrogen atom bonded to nitrogen atom concerned this CH4 loss. Almost complete scrambling of CH3 groups occurs prior to loss of CH4. An unusual NH3 elimination was found in the MIKE spectra of the [M-CH3-CH4]+ ion for 1 and of the [M-CH3]+ ion for 2.
The fragmentations of 2 were compared with those of its carbon analogue, diisopropylamine, 3.View full abstractDownload PDF (518K) -
Hidetoshi FUJIWARA, Ichizo OKABAYASHI1991 Volume 39 Issue 1 Pages 29-34
Published: 1991
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSThe mass spectra of stereoisomers of five 4-dimethylaminocyclohexanol derivatives were recorded under electron ionization, and fragmentation patterns were elucidated by exact mass measurements and metastable ion analysis.
The mass spectra showed differences in relative intensities of molecular ions between cis and trans isomers. The most characteristic feature of the mass spectral behavior of the compounds was fragmentation reaction, based on ionization of dimethylamino or hydroxyl groups.View full abstractDownload PDF (401K) -
Tokishi HAYASHI, Hidemi TODORIKI, Yoshio IIDA1991 Volume 39 Issue 1 Pages 35-42
Published: 1991
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSA sensitive and reliable method is described for the determination of 1,2,3,4-tetrahydro-β-carboline and 1-methyl-1,2,3,4-tetrahydro-β-carboline in human urine, based on selected ion monitoring gas chromatography mass spectrometry coupled with use of deuterated analogues as internal standards. These compounds were extracted from a urine sample with ethyl acetate after pretreatment with fluorescamine and converted to trifluoroacetyl derivatives. The derivatives were separated by capillary gas chromatography and monitored by selected ion monitoring. For quantitation, the base peaks corresponding to each molecular ion were used as monitoring ions. The method developed in this work was used not only for the determination of 1,2,3,4-tetrahydro-β-carboline and 1-methyl-1,2,3,4-tetrahydro-β-carboline in human urine samples of healthy persons but also for a basic investigation of their in vivo metabolism using a deuterium labeled compound.View full abstractDownload PDF (471K)
TECHNICAL REPORT
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Kozo MATSUMOTO, Nobuyuki SATO, Shin TSUGE, Masashi TAGUCHI1991 Volume 39 Issue 1 Pages 43-47
Published: 1991
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSA combination system of capillary supercritical fluid chromatography (SFC) with a use of CO2 as a mobile phase and mass spectometry (MS) was developed by using a vacuum nebulizing interface. Application of the vacuum nebulizing interface enabled the operation of the SFC/MS system at a high pressure up to ca. 400 kg/cm2 attained by SFC pump. By adjusting the flow rate of the nebulizing gas, vacuum of the mass spectrometer was easily controlled for chemical ionization condition. In addition, the use of isobutane as a nebulizing gas enabled stable and continuous introduction of the sample into the ion source to attain soft ionization. Analytical conditions of this SFC/MS system were epitomized for caffeine as a test sample. The system was also applied to the analysis of polyethylene glycol-400.View full abstractDownload PDF (348K)
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