巻号一覧
43 巻 (1995)
- 6 号 p. 325-
- 5 号 p. 225-
- 4 号 p. 165-
- 3 号 p. 127-
- 2 号 p. 109-
- 1 号 p. 1-
43 巻, 5 号
選択された号の論文の7件中1～7を表示しています
- |<
- <
- 1
- >
- >|
総合論文
-
武部 雅汎, 佐藤 義之, 飯沼 恒一1995 年 43 巻 5 号 p. 225-238
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーThe interaction potential between the Li+ ion and neutral atoms or molecules (Ar, Kr, Xe, N2, and O2) can be estimated from the ionic mobilities measured in gases. Assuming Langevin reaction coefficient as a limiting value, we have plotted experimental reverse Li+ ion-clustering reaction coefficients as Arrhenius plot and the activation energies for the reverse ion-clustering reactions were estimated. We found a good relationship between the activation energies and the well depth of the potential between the Li+ ion and the neutral atoms or molecules estimated from the mobility measurement. We also found a relationship for the forward reaction coefficients, which can be deduced from the Langevin reaction coefficient and the mean trapping time calculated from the interaction potential. The quadrupole moment for the diatomic molecule such as N2 and O2, plays an important role in forward ion-clustering reaction of Li+ ions.抄録全体を表示PDF形式でダウンロード (906K)
報文
-
S. HAYAKAWA, K. KADOMURA, K. FUJII1995 年 43 巻 5 号 p. 239-255
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーCharge inversion mass spectrometry measures negative ions formed both by double-electron-transfers in one collision and by successive single-electron-transfers in two collisions. Mechanism for H- ion formation in collisions of H+ ions with alkali metals has been studied by developing calibration methods of translational energy losses along with measurements of target density dependences in the charge inversion mass spectrometry. Two peaks with different translational energies were observed in magnified spectra of the peak associated with H- ions with Cs and K targets. One of the two peaks with the higher translational energy had higher intensity and showed a quadratic dependence on target density, while the other with the lower translational energy had lower intensity and showed a linear dependence on the target density. The translational energy difference was calibrated both by monitoring the magnetic flux density and by changing the accelerating voltage. The translational energy differences between the two peaks were evaluated as 10.7±0.4 eV and 17.4±0.5 eV with Cs and K targets, respectively. The translational energy differences of H- ions coincided with those of D- ions for both Cs and K targets. For Na target, only one peak with the quadratic dependence on the target density was observed. From the energy difference and the linear dependence on target density, the peak with the lower translational energy was ascribed to double electron transfer forming H-(1s2) ions in one collision. Existence of a double electron transfer process forming H-(1s2) and excited Cs2+(5s, 5p5) was suggested for a weak peak with the energy loss of about 34 eV with Cs target. The peak with the higher translational energy and the quadratic dependence was ascribed to three-step process which was composed of neutralization forming H(2p), spontaneous Ly-α emission from H(2p) and anionization forming H-(1s2) ions from H(1s).抄録全体を表示PDF形式でダウンロード (1007K) -
Yasumasa IKEZOE, Takeshi SOGA, Kazuya SUZUKI, Shin-ichi OHNO1995 年 43 巻 5 号 p. 257-263
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーCO2 laser induced photodissociations of NH4+·nNH3 and of ND4+·nND3 were examined by a tandem mass spectrometer (TMS). Photodissociation took place for NH4+·nNH3 with n≥5. No photodissociation was observed for ND4+·nND3. It depended on the laser intensity, wave number, and cluster size. The maximum yield of NH4+·5NH3 dissociation was obtained at 1080 cm-1, and that of NH4+·7NH3 shifted to 1075 cm-1. Two molecules dissociation was observed in addition to one molecule dissociation. The yield of one molecule dissociation increased linearly with the laser intensity, indicating that the dissociation is a single photon process. Elementary processes which affect isotope effect in the dissociation are discussed.抄録全体を表示PDF形式でダウンロード (444K) -
Kenzo HIRAOKA, Shinsuke KATAYAMA, Keiichi AIZAWA, Fumiko MATSUSHITA, H ...1995 年 43 巻 5 号 p. 265-277
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーA sudy on the application of infrared (IR) CO2 laser (10.6 μm) to the LC/MS interface was made. When the IR laser was irradiated on the tip of the quartz capillary tube with the sample flow rate of a few tens μl/min, intense alkaline ions (Na+ and K+) and O2-ion were observed. However, the ion signals originating from thermally labile samples could not be detected due to the thermal degradation. The tetraalkylammonium ions could be detected when the stainless steel capillary was used. Irradiation of IR laser near the tip of the Taylor cone of the electrospray promoted the efficient vaporization of charged liquid droplets resulted in the drastic increase of the sample ion signal. When SF6-containing N2 was used for the ion spray as a nebulizer gas, a drastic increase of the amino acid ion signals was observed. This is due to the enhanced evaporation of the charged liquid droplets caused by the efficient absorption of 10.6 μm IR laser by SF6 gas. When IR laser was irradiated on the electrosprayed charged liquid droplets for 10-5 M tubocurarine chloride (M) solution in isopropanol/aqueous NH3 (29%) solution, the intensity of the singly charged ion (M-HCl-Cl)+ increased but that of doubly charged ion (M-2Cl)2+ decreased. This may be due to the enhanced surface evaporation of the charged liquid droplets caused by the efficient absorption of IR laser by ammonia solution. The surface evaporation results in the increase of ions with larger surface activities but the ions with smaller surface activities are rather insensitive to the surface evaporation because they are mainly solvated not near the surface but inside the liquid droplets.抄録全体を表示PDF形式でダウンロード (802K) -
Mitsuo TAKAYAMA1995 年 43 巻 5 号 p. 279-291
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーThe formation of deprotonated molecules [M-H]- of Trolox having a carboxyl and a phenolic hydroxyl group and the derivatives, under fast-atom bombardment (FAB) conditions, has been examined from the viewpoint of proton-transfer reaction in gas-phase or solution. The negative-ion FAB mass spectra of the derivatives strongly suggested that deprotonation mainly occurs on the carboxyl group through the electrolytic dissociation in matrix solution. The use of higher proton acceptability matrices such as glycerol, pentamethylene glycol, and diethanolamine was favorable for the detection of [M-H]- ions of a Trolox methyl ester, while the use of lower proton acceptability matrices such as m-nitrobenzyl alcohol and dithiothreitol was unfavorable for the [M-H]- formation. While the result obtained suggested that the formation of [M-H]- ions reflects the gas-phase basicities of matrices used, the results from the negative-ion FAB mass spectra of the Trolox methyl ester and α-tocopherol suggested that the [M-H]- formation reflects solvation states such as hydrophobic and hydrophilic interactions between analyte and matrix molecules in matrix solution. The site of deprotonation of the compounds used has been examined by using collision-induced dissociation (CID) technique, and it was shown that the CID characteristics of [M-H]- ions depend markedly on the site of deprotonation. It was presumed, consequently, that the [M-H]- ion formation under FAB conditions is governed by gas-phase thermochemistry and/or solution chemistry according to the nature of analyte and matrix used.抄録全体を表示PDF形式でダウンロード (712K) -
岸 浩, 藤井 敏博1995 年 43 巻 5 号 p. 293-304
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーHyperthermal Surface Ionization Mass Spectrometry (HSIMS) has been performed on some alkyl alcohols with the ion source using rhenium oxide as an ion emitter and with a quadrupole mass spectrometer. Mass spectral results were obtained as a function of incident kinetic energy of organic molecules and system parameters, indicating that kinetic energy caused the surface ionization to increase drastically above threshold energy. The mass spectra were presented, interpreted in a purely empirical way and they were compared with conventional EIMS.
In summary, a) alkyl alcohols are efficiently surface-ionized, b) abundant even electron ions (EE+) are observed generally in the HSIMS, c) in addition to these EE+ ions, strong radical cations such as (M-2·H)+· are observed, d) soft ionization can be obtained in general, where the quasi-molecular ion (M-·H)+ and quite a few fragments are generated, e) on the basis of these mass spectral findings, it is concluded that radical species are first generated by thermal dissociation, followed by the ionization of these species on the surface, f) characteristic mass spectral patterns for isomers were obtained, indicating that HSIMS can be usefully applied for the characterization of isomers.抄録全体を表示PDF形式でダウンロード (644K)
解説
-
宮崎 哲郎1995 年 43 巻 5 号 p. 305-312
発行日: 1995年
公開日: 2007/07/20
ジャーナル フリーTunneling reactions of ions produced by radiolysis in the solid phase at low temperature have been reviewed. First, the clear evidences for tunneling reactions were shown in the reactions H(D)+H2 (D2, HD) that are the simplest fundamental reaction. Second, a large isotope effect on a proton transfer reaction from ethanol to benzene anions at 77 K was interpreted in terms of a tunneling effect. Third, a tunneling detachment of a H2 molecule from a 2,3-dimethylbutane cation was observed at 77 K. Fourth, it is concluded here that the tunneling reaction in the solid phase at low temperature is affected by motions of reactive species and surrounding molecules. Thus, the rate constant (kT) for the reaction is expressed as follows. kT=k(tunnel)×F(motion), where k(tunnel) is the rate constant for a tunneling process itself and F(motion) represents the motion of molecules.抄録全体を表示PDF形式でダウンロード (475K)
- |<
- <
- 1
- >
- >|