Journal of the Mass Spectrometry Society of Japan

In-beam EI and In-beam CI Mass Spectrometry

Mamoru Ohashi

1979 Volume 27 Issue 1 Pages 1-15
Published: March 31, 1979
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5702/massspec1953.27.1

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Design and Performance of APrism Mass spectrometer

Taichi Shino, Isao Takesita, Hideo Tanaka

1979 Volume 27 Issue 1 Pages 17-29
Published: March 31, 1979
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5702/massspec1953.27.17

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A mass spectrometer consisting of two Q lenses and a prism magnet of 90° Kdeflection with parallel pole edges is designed and constructed. The radius of the ion trajectory in the magnetic field is 120mm. This optical system can make the instrument compact, as the magnet dimension can be chosen independently of resolving power. Three source or collector slits with different widths of 0.5, 0.1 and 0.02mm are mounted on a plate and one of them can be chosen according to the required resolving power. Two types of ion detector, i. e. a Faraday collector and an electron multiplier are placed behind two of the three collector slits and mass spectra are simultaneously recorded with different resolving power and sensitivity. The adjustment of the simultaneous focusing at two collector slits is achieved electrically by the rotation of a focal line. The resolving power obtained is 140, 670 and 3, 000, using the respective slit widths. The ion source sensitivity is 1 × 10 ^-5 A/Torr.(Ie=100 μ A, Uacc=2, 500V, Res.=140)The ion accelerating potential is variable from 500 to 2, 500V with the stability of 10ppm/°C The magnetic field is scanned exponentially and mass spectra are plotted on a linear mass scale with a strip chart recorder driven by a pulse motor. The scanning time from M=11 to 500 is about 7 minutes.

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Ionization Efficiency Curves of C2D2 by Electron Impact

Isao H. Suzuki, Kogoro Maeda

1979 Volume 27 Issue 1 Pages 31-40
Published: March 31, 1979
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5702/massspec1953.27.31

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Ionization efficiency curves have been measured for the ions produced from C2D2 by monoenergetic electron impact over ranges of about 10 eV near their appearance thresholds. The breaks in the total ionization efficiency curve were found to correspond to the ionic and autoionizing states of C2D2. The curve was reproduced by using a simulation technique, and the degrees of contribution from those states to the total ion intensity were estimated. The total contribution from all autoionizing states was found to reach 40% near 16 eV. This degree of C2D2 is higher than that of C2H2 below 20 eV. No indication of isotope effect was found on the appearance potentials of the fragment ions.

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Theoretical Basis on the Bond-scission by Electron Bombardment

Kozo Hirota, Kichisuke Nishimoto, Masao Yamamoto

1979 Volume 27 Issue 1 Pages 41-46
Published: March 31, 1979
Released on J-STAGE: March 01, 2011

DOIhttps://doi.org/10.5702/massspec1953.27.41

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The theoretical basis on the rule for fast initial bond-scission proposed by the present authors has been proposed, discussing the relation with the slow bond-scissions which obey QET.

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Mass Spectra of 7H-Thiazolo[3, 2-a]Pyridine Derivatives(II)

Hiroshi Kishi, Satoshi Kambe

1979 Volume 27 Issue 1 Pages 47-52
Published: March 31, 1979
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5702/massspec1953.27.47

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Mass spectra of 6, 8-dicyano-7H-thiazolo[3, 2-a]pyridine derivatives were measured by electron impact ionization mass spectrometry. The substituents on the phenyl groups were H (Compound I), p-CH3(II), p-OCH3(III), p-Cl(IV), p-NO2(V), m-NO2(VI). The deuterated compounds of 2, 7-D2(VII) and 5-ND2(VIII) were also examined. The fragmentation patterns were deduced with the aid of the shifts of the peaks by substituted groups and by deuterated derivatives, and some of them were confirmed by the metastable peaks. The fragmentation patterns were quite different from those of 6, 8-dialkoxycarbonyl derivatives. The temperature dependence of mass spectra was tested, and the increase of fragment ion intensity by chamber temperature was observed in the thiazolo-ring opening fragmentation. But other fragment ions did not change their intensity by chamber temperature.

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Chemical Ionization Mass Spectrometry of Flavonoids.I.

—5-Hydroxy-6, 7-dimethoxyflavone-4'-glucosides—

Mitsuru Nakayama, Shizuko Eguchi, Shûichi Hayashi, Tokunaru Hori ...

1979 Volume 27 Issue 1 Pages 53-58
Published: March 31, 1979
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5702/massspec1953.27.53

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Ammonia and isobutane chemical ionization mass spectra of the intact flavone glycosides are described. The protonated molecular ion(MH+) are peaks very weak and glycosidic bond cleavage is observed as the major fragmentation pathway. Consequently, the mass spectra exihibit the protonated aglycone ions as the base peak and the various sugar-derived ions.

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Mass Spectra of Some ent-15-ketokauranoids

Shizuko Eguchi, Seiryu Uto, Akihiko Matsuo, Mitsuru Nakayama, Shuichi ...

1979 Volume 27 Issue 1 Pages 59-68
Published: March 31, 1979
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.5702/massspec1953.27.59

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Mass spectra of three naturally occurrig ent-15-ketokauranoids, (I), (III)and(IV), and their derivatives, (II)and(V), were measured and their characteristic fragmentations were discussed.

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