巻号一覧
43 巻, 1 号
選択された号の論文の11件中1～11を表示しています
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Teruyuki MARUOKA, Jun-ichi MATSUDA1995 年 43 巻 1 号 p. 1-8
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーFor precise measurements of noble gases with a mass spectrometer, we need to separate each noble gas by adsorptive phenomena at low temperatures. We made adsorptive experiments for Ar, Kr, and Xe using a cold trap containing a sintered stainless steel filter element. In this paper, we applied a simple model to our experimental observations in order to better understand the adsorptive phenomena on the adsorbent, and obtained the conditions for more efficient separation of individual noble gas. The results suggest that the adsorption curves shift to a higher temperature when we release gas in a smaller volume of the extraction line. This temperature shift is larger for a noble gas with a higher mass. Therefore, small volume of preparation line is suitable for the clear separation of noble gases. It is also shown that the adsorption curve depends on the pressure of gases when the total number of gas atoms in the line is not negligible compared to the maximum number of atoms being adsorbed.抄録全体を表示PDF形式でダウンロード (471K) -
Toru SAKURAI, Morio ISHIHARA1995 年 43 巻 1 号 p. 9-17
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーIon trajectories in the extended fringing fields of an electrostatic sector analyzer have been calculated algebraically. The results of the calculations are represented by the transfer matrices for the entrance and exit fringing fields, respectively. The matrix coefficients yield a shift and bend of ion trajectories on a transformation plane at field boundaries of the sector. The effects of the extended fringing fields on image aberration can be estimated from the matrix coefficients. Large effects from the fifth order matrix coefficients have been found for the fringing fields of an electrostatic sector analyzer. The image aberration arising from the fifth order coefficients is one of the problems in obtaining high resolution with a double focusing mass spectrometer.抄録全体を表示PDF形式でダウンロード (400K) -
Hirohisa ISHIMARU, Yasushi IKARASHI, Yuji MARUYAMA, Susan T. WEINTRAUB1995 年 43 巻 1 号 p. 19-26
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーThe use of stable isotope analogs and accurate mass analysis has permitted elucidation of the continuous-flow fast atom bombardment mass spectral fragmentation of the neurotransmitter, acetylcholine. These studies showed that the major fragmentation pathway involved loss of trimethylamine from the intact molecular cation and that formation of an ion at m/z 58 proceeded through two different routes. Losses of acetic acid and ketene were observed in addition to the generation of cationized trimethylamine.抄録全体を表示PDF形式でダウンロード (447K) -
Fumiko NISHIDA, Katsuyoshi MASUDA, Ken-Ichi HARADA, Makoto SUZUKI, Vit ...1995 年 43 巻 1 号 p. 27-35
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーThe structures of the glycosidic antibiotics, the glykenin (GK) family, produced by Basidiomycetes sp. were characterized using frit-FAB LC/MS. The GK was separated into nine components (GK-I-VII and DG) with differences in the number and positions of the acetyl groups in the sugar moiety. Although each of these components is further composed of three isomers depending on the three aglycones, it was difficult to isolate individual components because of the presence of the labile acetyl groups in the sugar moiety. For this reason, frit-FAB LC/MS in the negative ion mode was used for the structure characterization of each component. Three peaks were found in the mass chromatogram of each GK component monitored for the molecular ion species. The fragment ions related to the aglycone and sugar moieties were observed in each mass spectrum. Their molecular weights, the locations of the acetyl groups and the presence of three aglycones were confirmed using these ions. Furthermore, a profile analysis of the GK mixture was possible using a gradient elution mode.抄録全体を表示PDF形式でダウンロード (576K) -
Fumiko NISHIDA, Ken-Ichi HARADA, Makoto SUZUKI, Tsuyoshi FUJITA, Hideo ...1995 年 43 巻 1 号 p. 37-44
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーThe exact positions of the acetyl groups in the sugar moieties of the glycosidic antibiotics, the glykenin (GK) components, were elucidated using MS/MS technique under high energy collision conditions, because the frit-FAB LC/MS technique that was described in a preceding paper and other techniques were insufficient for the purpose. In the negative product ion spectra of (M-H)-, a charge-remote fragmentation based on a terminal carboxylic acid of the aglycone was observed, whereas many cleavage ions were observed in the positive product ion spectra of (M+Li)+. The diagnostic ions were selected from the cleavage ions of two bonds within the glycosidic ring in the product ion spectra of the (M+Li)+ and (M-H)-. The positions of the acetyl groups for each component could be determined by the presence or absence of these diagnostic ions, which enabled us to determine the structure of each of the GK components.抄録全体を表示PDF形式でダウンロード (461K) -
Naoto SENDA, Yutaka KUBOTA, Takuji HOSHINO, Hiroshi NOZAKI, Hideo HAYA ...1995 年 43 巻 1 号 p. 45-51
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーIt is generally known that specimens of Carex species plants are resistant to insects and contain a variety of stilbene compounds. Some stilbene oligomers obtained from four kinds of Carex plants were analyzed by mass spectrometry. The electron impact mass spectra, secondary ionization mass spectra, and B/E linked scan spectra were measured to investigate their fragmentations.抄録全体を表示PDF形式でダウンロード (301K) -
Takae TAKEUCHI, Noriko MURATA, Yoshiko YOKOTA, Yoko KYOYA, Kaoru IWAI, ...1995 年 43 巻 1 号 p. 53-63
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーThe unimolecular dissociation of the butylmethylsilane, butyldimethylsilane, and butyltrimethylsilane ions in EI mass spectrometry has been investigated using the deuteriumlabeling technique and the B/E linked scanning method. The EI mass spectra of these alkylsilanes were characterized by the formation of silyl cation, [(CH3)nSiH3-n]+ (n=1-3), due to the cleavage of an Si-C bond and the formation of [(CH3)nSiH3-nCH2=CH2]+ due to the cleavage of a Cβ-Cγ bond. The stabilization due to an Si-C hyperconjugation is found to be a driving force to produce [CH3SiH2CH2CH2]+ from butylmethylsilane ion and [(CH3)2SiHCH2CH2]+ from butyldimethylsilane ion, respectively. The present results show that the intensities of [(CH3)nSiH3-n]+ and [M-CH3]+, increase in the order of butylmethylsilane butyldimethylsilane butyltrimethylsilane, and that of [(CH3)nSiH3-nCH2CH2]+ increases in the reverse order. The EI mass spectra of the deuterium-labeled compounds show that [M-CH3]+ is produced due to the cleavage of an Si-CH3 bond. [M-H]+ in EI mass spectra of butylmethylsilane and butyldimethylsilane is produced due to the loss of a hydrogen atom connected to the Si atom. H2 elimination from the butylmethylsilane ion occurs due to 1,4-H2 elimination via a four-membered ring formation or 1,1-H2 elimination due to a loss of two hydrogen atoms connected to the Si atom.抄録全体を表示PDF形式でダウンロード (560K) -
Kenzo HIRAOKA, Ichiro KUDAKA, Shinichi YAMABE1995 年 43 巻 1 号 p. 65-75
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーThermochemical stabilities of O2+(Ar)n, O4+(Ar)n, and O6+(Ar)n were determined with a pulsed electron-beam mass spectrometer. All ions Om+ with m=2, 4, and 6 are found to accommodate two Ar atoms favorably; shell structures, Om+(Ar)2(Ar)n-2 are formed. The structures of O2+(Ar)2, O4+(Ar)2, and O6+(Ar)2 were discussed based on ab initio calculations.抄録全体を表示PDF形式でダウンロード (635K) -
Kenzo HIRAOKA, Keiichi AIZAWA, Konosuke MURATA, Susumu FUJIMAKI1995 年 43 巻 1 号 p. 77-83
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーIodine (I2) was found to be detected as I- with high sensitivity when solution of iodine in i-C3H7OH-H2O-CHCl3 (8:2:0.5, v/v) was electrosprayed in the negative ion mode. The strong appearance of I- in electrospray mass spectra is due to the reduction of I2 to I- at the liquid/metal interface of the electrospray capillary needle. When the concentration of iodine in solution was increased (≥ 10-5 M)), the negative ions I3- and I5- as well as I- were observed. The lower limit of iodine concentration for the detection of I2 as I- was ~10-9 M. This indicates that the electrospray ionization mass spectrometry could be the new method for the analysis of iodine with high sensitivity.抄録全体を表示PDF形式でダウンロード (433K) -
Toshihide NISHIMURA, Mitsuo TAKAYAMA1995 年 43 巻 1 号 p. 85-96
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーGas-phase fast atom bombardment (GFAB) mass spectra of the chromium hexacarbonyl molecule were compared with its charge-exchange ionization (CEI) mass spectra. It was found that the fragmentation pattern of chromium hexacarbonyl ions obtained by He-CEI mass spectrometry most resembles those measured in GFAB, and so it seems that energy deposition during GFAB implies involvement of a resonance-like energy transfer from fast atoms and may be similar or higher than that in He-CEI reaction. No great difference was observed in GFAB mass spectrum for a variety of fast bombarding particles including He, Ar, Xe, Cs, and isobutane. A high pressure GFAB mass spectrum of trolox measured using a Cs beam demonstrated its reactive nature that exchange reaction between hydroxy protons and Cs+ ions seems to take place in gas phase for the molecule and its neutral fragments while a Cs-FAB mass spectrum measured under a relatively low sample gas pressure showed only a fragmentation pattern characterized by a high abundance of fragment ions. Since Cs is only an alkali metal among fast bombarding particles, its chemical nature may be responsible for the observed reactivity with the target molecule.抄録全体を表示PDF形式でダウンロード (625K) -
Kimio OKAMURA, Yoshio SUMIDA, Yasuhiro FUJIWARA, Syunji TERADA, Haedeu ...1995 年 43 巻 1 号 p. 97-105
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーThe stereospecific ion-molecule reaction between optically resolving agents (a pair of enantiomers of mandelic acid, methyl mandelate, and 1-phenylethylamine) and several enantiomers of amino acids were investigated by high performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (HPLC/APCIMS). On the APCI mass spectra, the 1 : 1 adduct ion [M…H…X]+ that the amino acid molecule [M] reacted with the protonated optically resolving agent in mobile phase [XH]+ has been prominently observed. The results show that the relative abundances of 1 : 1 adduct ions [M…H…X]+ formed from samples (amino acids) and reagents (resolving agent) of the same configuration (homo-chiral) are much higher than those of different configurations (hetero-chiral). To support this hypothesis, we carried out X-ray crystallographic analysis on diastereomeric complexes of (S)-phenylalanine with (R)- and (S)-mandelic acid for a resolving agent as a model compound. The crystal structure obtained was in accordance with the stereochemical effects observed in APCIMS.抄録全体を表示PDF形式でダウンロード (495K)
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