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Volume 28 (1980)
- Issue 4 Pages 277-
- Issue 3 Pages 211-
- Issue 2 Pages 143-
- Issue 1 Pages 75-
Volume 28, Issue 3
Displaying 1-8 of 8 articles from this issue
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ORIGINAL PAPERS
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Hisashi Matsuda1980 Volume 28 Issue 3 Pages 211-215
Published: 1980
Released on J-STAGE: May 01, 2007
JOURNAL FREE ACCESSA new type of double focusing mass spectrometer is proposed. The apparatus consists of a hybrid electric field, a Q-lens and a homogeneous magnetic field with curved boundaries. It has focusing nature of both second order and stigmatic, besides the image magnification is only 0.1. Therefore, very high sensitivity is expected at high resolution because 10 times wider source slit is possible to use comparing with the conventional mass spectrometer. The distinguishing feature of this ion optical system is that the electric field is divided into two parts, one is a diverging field with c>2 and the other a converging field with c<2. The first electric field makes a small virtual image and this virtual image is focused by the second electric field at the exit of the electric field. The image aberration due to the influence of the fringing field is reduced by the small beam size at the boundary. Several examples of the ion optical systems are described.View full abstractDownload PDF (309K) -
Takehiro Takeda, Sumio Shibata, Hisashi Matsuda1980 Volume 28 Issue 3 Pages 217-226
Published: 1980
Released on J-STAGE: May 01, 2007
JOURNAL FREE ACCESSAccelerating voltage scanning mass spectrometer was designed and constructed in order to obtain high speed scanning. The retarding type ion source was used in order to increase the extraction efficiency of the ion source at low accelerating voltage.
The constructed mass spectrometer is a modified Mattauch-Herzog double focussing one and the mass range from 12 to 500 is obtained by adopting two different ion paths in the magnetic field.
The results of scan time (faster than 50μsec/1mass), sensitivity (10pg/1μl for benzophenone) and resolution are sufficient for practical use.View full abstractDownload PDF (521K) -
Etsuo Yamauchi, Tokuo Mizuno, Koushi Azuma1980 Volume 28 Issue 3 Pages 227-234
Published: 1980
Released on J-STAGE: May 01, 2007
JOURNAL FREE ACCESSA direct coupling interface with a variable splitter is developed for a connection of a micro-liquid chromatography and a magnetic type mass spectrometer.
50 % sample transmission efficiency, 0.1 ng detection limit and less than 25% peak broadness are obtained.
Application of the interface for various less volatile samples such as steroid hormons and vitamins are discussed.View full abstractDownload PDF (387K) -
Masahiko Tsuchiya, Kazushige Seita, Tetsuji Taira1980 Volume 28 Issue 3 Pages 235-241
Published: 1980
Released on J-STAGE: May 01, 2007
JOURNAL FREE ACCESSWe have developed a method of ionization (liquid ionization method) for organic compounds in the lipuid phase at atmospheric pressure. Major ions produced by this method are MmH+ ions which can be measured at pinhole potential of less than 20 V. The number m is 1 and 2 for most of the compounds measured, even for less volatile compounds like amino acids. Several fragment ions measured at pinhole potential of around 50V are similar to those obtained by CI and the ions measured at higher pinhole potential become partly similar to those obtained by EI. Therefore, the mass spectrum obtained by this method is quite useful for determining the structure of a compound.
Mass spectra of a synthetic compound, a kind of oligomer, were measured by this method and its molecular weight and the structure of the compound were determined. This is the largest compound (M.W.=536) we have measured so far.View full abstractDownload PDF (389K) -
Yukiko Nakajima, Michihiko Ogata, Hiroshi Ichikawa1980 Volume 28 Issue 3 Pages 243-247
Published: 1980
Released on J-STAGE: May 01, 2007
JOURNAL FREE ACCESSIn searching adequate MO theories for calculation of the sizable system of doublet state, the unrestricted version of MINDO/3 has been examined in various radicals to show that the unrestricted MINDO/3 (UMINDO/3) method has an advantage over the conventional MINDO/3 in that it gives faster geometrical and SCF convergences and more accurate vertical ionization energies for π-conjugate radicals.View full abstractDownload PDF (287K) -
Masatsune Oda1980 Volume 28 Issue 3 Pages 249-262
Published: 1980
Released on J-STAGE: May 01, 2007
JOURNAL FREE ACCESSThe mass spectra of anilides represented general formula o- or p-ClC6H4NHCOR (R=H,CH3~C3H7, i-C3H7) and substituted formanilides (R=H) and acetanilides (R=CH3) were measured to determine the effect of R and substituent on anilide fragmentation.
The mass spectra of anilides of R = CH3~C3H7, i-C3H7 independent of length of R indicated almost the same fragmentation, qualitatively and quantitatively except for the -CO-R bond simple cleavage in R=C2H5, C3H7, i-C3H7. But, those of formanilides were characterized by fairly strong M+·, strong fragments produced from [M-ketene]+·, prominent o-effect ([M-Cl]+) and weak fragments produced through the -NH-CO- bond cleavage involving ketene elimination, and little HC≡O+.
In investigations of mono substituted formanilides and acetanilides, it was found that o-isomeres (Cl, NO2, NH2, CH3, C2H5) produced specific fragment ions but almost all p- and m-isomeres didn't. This o-effect was stronger in formanilides than in acetanilides and [M-OH]+ ions from o-alkyl isomeres were recognized only in formanilides.
It was concluded that three isomeres (o-, m-, or p-) in nitroformanilide, methoxy-formanilide, aminoformanilide and aminoacetanilide could be identified.View full abstractDownload PDF (713K) -
Shizuko Okada, Yoshio Iida1980 Volume 28 Issue 3 Pages 263-268
Published: 1980
Released on J-STAGE: May 01, 2007
JOURNAL FREE ACCESSA simple and sensitive method for the determination of thirteen impurities in n-hexane or n-heptane by GC/CIMS is presented. One to three μl of sample is injected into a Finnigan 3300E GC/CIMS instrument equipped with a 5 m × 2 mm i.d. glass column packed with 5% squalane/Uniport K (80~100 mesh), and the mass fragmentograms of the specific peaks due to QM+ are recorded. The peaks used are as follows: m/z 69 for cyclopentane, 71 for 2-methylbutane and n-pentane, 79 for benzene, 83 for methylcyclo-pentane and cyclohexane, 85 for 2-methylpentane, 3-methylpentane and n-hexane, 93 for toluene, 97 for methylcyclohexane, 99 for 2-methylhexane, 3-methylhexane and n-heptane. Methane is used both as carrier and reactant gas. Owing to high selectivity and sensitivity of the proposed method, satisfactory results were obtained without the complete GC separation. The determination limit was 10~200 pg with a precision of about 5%. The total impurities in n-hexane or n-heptane samples which are all reagent chemicals were found to be 0.11~2.9%.View full abstractDownload PDF (338K) -
Shigeki Daishima, Yoshio Iida1980 Volume 28 Issue 3 Pages 269-275
Published: 1980
Released on J-STAGE: May 01, 2007
JOURNAL FREE ACCESSThe CI mass spectra of C8H10 and C9H12 alkylbenzene possessing four and eight isomers respectively, were evaluated for the the purpose of their isomeric distinction and identification. About 2μg of each isomer in acetone was introduced into a Finnigan 3300E GC/QMS system equipped with an OV-1 or Squalane column. The ion source conditions were CH4 (1 Torr), i-C4H10 (0.5 Torr) at 70°C. The relative standard deviation was 1~10% for thrice repeated measurements and also 1~20% on another day. In CH4 reagent gas, (M-27)+ peak only appeared in ethylbenzene and ethyltoluene, while C3H7+, (M-41)+ and (M-13)+ was only given by propylbenzene. Since there was a considerable difference in the intensity ratio of (M-15)+, (M-1)+, M+ or (M+57)+ to (M+1)+ when using i-C4H10 as reagent gas, distinction of isomers among each alkylbenzene was possible. It was found that the CI mass spectra using CH4 reagent gas were advantageous for grouping C8H10 and C9H12 isomers, whereas those using i-C4H10 reagent gas were suitable in distincting and identifying each isomer. The CI method was superior to EI method concerning this study.View full abstractDownload PDF (422K)
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