巻号一覧
50 巻 (2002)
- 6 号 p. 286-
- 5 号 p. 213-
- 4 号 p. 173-
- 3 号 p. 100-
- 2 号 p. 52-
- 1 号 p. 1-
50 巻, 6 号
選択された号の論文の9件中1～9を表示しています
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報文
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Seiko NAKAGAWA2002 年 50 巻 6 号 p. 286-289
発行日: 2002年
公開日: 2007/10/16
ジャーナル フリーThe temperature dependence for the formation of negative ions from Cl2BrC-CBrCl2, FClBrC-CBrF2, and ClBr2C-CF3 was studied using negative chemical ionization mass spectrometry. Halide ions and halogen molecular anions were observed. The intensity ratios between the halide ions and halogen molecular anions were almost equal to F2BrC-CBrF2. Halogen molecular anions are produced from halogen atoms presented by each C atom: the four-center elimination. The temperature dependence of the ion intensity ratios, Br-/Cl- and Br2-/BrCl-, suggests that the strength of the bonding energy of the C-Cl relative to C-Br increases in the order of Cl2BrC-CBrCl2<FClBrC-CBrF2<ClBr2C-CF3.抄録全体を表示PDF形式でダウンロード (201K) -
Motohiro SHIZUMA, Hitoshi YAMADA, Hiroshi ADACHI, Yoshio TAKAI, Tokuji ...2002 年 50 巻 6 号 p. 290-295
発行日: 2002年
公開日: 2007/10/16
ジャーナル フリーThe FAB mass spectrometry (MS)/enantiomer labeled (EL) guest method is one of the useful technique to easily evaluate chiral discrimination ability of a chiral host (H) toward chiral guests (GR+, GS-dn+). In this paper, the matrix dependency of the relative peak intensity (IRIS) of the diastereomeric host-guest complex ions [(H+GR)+ and (H+GS-dn)+] was investigated (host, MeFruNys; guest, Phe-O-iPr+). The IRIS values of spectra measured using NBA, NPOE, and DTDE matrices agreed almost with the ratio of concentrations of the complex ions calculated from the association constants (KR and KS) in chloroform at 298 K. While, the IRIS values of spectra using glycerol matrix reached almost unity. It was assumed that the IRIS values depend upon the matrices used since the difference of solvation ability of the matrices affects the actual concentration of the guest concerning in the complexation. And then, it was recommended that NBA is the best matrix for chiral recognition mass spectrometry studies.抄録全体を表示PDF形式でダウンロード (479K) -
Jintao HUANG, Tomohiro FURUKAWA, Kazumi AOTO, Michio YAMAWAKI2002 年 50 巻 6 号 p. 296-300
発行日: 2002年
公開日: 2007/10/16
ジャーナル フリーElectron impact ionization is a common way to provide positive ions for mass spectrometry. For most of molecular vapor species, however, experimental values of their electron impact ionization cross-sections are so limited that theoretic estimations become necessary. It is found that classic model such as additive rule or its modified version is no longer valid near the ionization threshold. Knowledge in this area is important for alkaline metals like sodium because their molecules may reach the maximum cross-section just a few eV above the ionization potential and easily crack in higher incident energies. A Binary-Encounter-Bethe (BEB) model developed by NIST was employed to calculate the cross-sections of NaO, NaOH, Na2, and Na2O molecules. The total ionization cross-section is computed from partial cross-sections of molecular orbitals. Gaussian and GAMESS code were employed to calculate the necessary molecular orbital parameters in the ground state. Calculated cross-sections were plotted as a function of electron impact energy. Reliability of the data predicted by BEB model was investigated by measuring corresponding ionization efficiency curves for some of the molecules. It was found that I(E)/Imax is generally equal to σ(E)/σmax within 15% in the testing range from 5 to 30 eV for sodium-containing molecules. It indicates that the BEB predictions seem correct at low electron incident energies.抄録全体を表示PDF形式でダウンロード (262K)
ノート
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Koichi METORI, Yumiko KIMURA, Muneharu MIYAKE2002 年 50 巻 6 号 p. 301-303
発行日: 2002年
公開日: 2007/10/16
ジャーナル フリーSome obstacles for the analysis of host-guest complexes by proton nuclear magnetic resonance (1H NMR) are the problem of requiring for a large excess of host, high concentration and high solubility of host and guest in order to get a good resolution. By 1H NMR spectrometry it is very difficult to detect the complex which the peaks of guest become overlapped by host peaks. Our primary purpose in this report is to judge if fast atom bombardment mass spectrometry (FAB-MS) is a suitable measurement tool for the determination of the host-guest complex stoichiometry in stead of 1H NMR spectrometry.抄録全体を表示PDF形式でダウンロード (170K) -
Mitsuo TAKAYAMA2002 年 50 巻 6 号 p. 304-310
発行日: 2002年
公開日: 2007/10/16
ジャーナル フリーThe susceptibility to in-source decay (ISD) in myoglobin, using matrix-assisted laser desorption/ionization (MALDI) coupled with a delayed extraction reflectron time-of-flight (TOF) mass spectrometer, has been described from the standpoint of secondary structures. The ISD data of three different myoglobins showed a common intense product of c35 ion originated from the cleavage of amine bond N-Cα at Gly35-His36 or Ser35-His36 residues. It is suggested that the relatively abundant formation of c35 ion in Gly35-His36 or Ser35-His36 residues is not due to the presence of His36 residue, but due to a turn region between helices in secondary structure of myoglobins.抄録全体を表示PDF形式でダウンロード (669K)
総合論文
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澤田 正實2002 年 50 巻 6 号 p. 311-329
発行日: 2002年
公開日: 2007/10/16
ジャーナル フリーThe developments of our quantitative chiral recognition studies in the host-guest complexations between chiral crown ethers and chiral amino acid esters by FAB, ESI, and MALDI mass spectrometry have been described. Both the enantiomer labeled (EL)-guest method and the EL-host method, which had been previously proposed by us, were successfully advanced. The relative peak intensity (IRIS) values of the diastereomeric host-guest complex ions appeared in mass spectra were especially noted, and their use to chiral recognition was illustrated. Generally, the former method was used to chiral recognition ability-determination of a given host, and the latter one was used to enantiomeric excess (e.e.)-determination of a given guest. Through the manuscript, emphasis has been put on the finding that one can detect correctly the concentration ratio of the two diastereomeric host-guest complex ions formed in a matrix solution by FAB mass spectrometry and then, that FABMS is a powerful tool for detecting chiral host-guest interactions in the host-guest complexation systems. Recent ,e.e.-determination methods by ESI mass spectrometry etc. were also summarized.抄録全体を表示PDF形式でダウンロード (1140K)
報文
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中川 由美子, 橋本 豊2002 年 50 巻 6 号 p. 330-336
発行日: 2002年
公開日: 2007/10/16
ジャーナル フリーPolar derivatization method for electrospray ionization mass spectrometry (ESI-MS) was developed and applied to the sensitive analysis of 5α-dihydrotestosterone (DHT) in prostate and plasma. Rat prostate was dissolved with alkaline solution and DHT in the prostate was extracted by solid phase extraction, and derivatized to the N-methylpyridinium-DHT as a polar derivative. The N-methylpyridinium derivative of DHT was purified by solid-phase extraction using Bond Elut C18, and determined by a semimicro-LC/ESI-MS with selected reaction monitoring (SRM). Linear responses of the N-methylpyridinium derivative of DHT were observed for analyte concentration from 5 to 100 pg/tube. DHT values were 12.0±3.8 ng/g tissue in rat prostates, 171.7±127.2 pg/mL in rat plasma and 286.2±123.5 pg/mL in human plasma.抄録全体を表示PDF形式でダウンロード (728K)
速報
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Hydrogen-Attachment Dissociation (HAD)高山 光男2002 年 50 巻 6 号 p. 337-349
発行日: 2002年
公開日: 2007/10/16
ジャーナル フリーIn-source decay (ISD) combined with matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometer (TOF MS) has been described by comparing with conventional mass spectrometric degradation (MSD) methods such as collision-induced dissociation (CID) and post-source decay (PSD). The ISD characteristic is the formation of c- and (z+2)-ions originated from the N-Cα bond cleavage on the peptide backbone, while the CID and PSD processes are the CO-NH bond cleavage which brings about b- and y-ion. Furthermore, the ISD processes occurring with 337 nm laser photon irradiation for peptide or protein proceed resulting in the formation of hyper-valent radical species via intermolecular hydrogen transfer between matrix and analyte molecules following the non-ergodic N-Cα bond cleavage. The non-ergodic N-Cα bond cleavage occurs in the MALDI ion source within nanosecond order, as an α-cleavage initiated with radical site at the carbonyl carbon. The MALDI-ISD method has been applied to three peptides and five proteins.抄録全体を表示PDF形式でダウンロード (2160K) -
渡辺 誠, 江口 大介, 佐藤 哲也, 平岡 賢三2002 年 50 巻 6 号 p. 350-352
発行日: 2002年
公開日: 2007/10/16
ジャーナル フリーSecondary ions produced by 400 eV He+ ion impact on Ar, Kr, and Xe thin films deposited on a silicon substrate at 8 K were measured as a function of film thickness using a time-of-flight secondary-ion mass spectrometer. For Ar, the cluster ions Arn+ up to n=4 as well as the monomer ion (n=1) were observed and they showed characteristic film-thickness dependence with increase of the film thickness up to ~200 monolayers. This is due to the momentum transfer in the elastic collision between the incident He+ ion and the matrix Ar atoms and also to the relaxation of electronic excitations (e.g., holes and excitons) to phonons resulting in the film erosion. In contrast, neither dimer nor cluster ions were detected for solid Kr and Xe films. This is due to the less efficient momentum transfer in the elastic collision between He+ and Rg's (Rg=Kr and Xe) and also to the efficient electronic energy migration in solid Kr and Xe. The C+ ions originating from the carbonic contaminants on the silicon substrate were found to be sensitized by the deposition of rare gas films. The penetration depths of the primary ion He+ through the rare gas films increase in the order of Ar<Kr<Xe.抄録全体を表示PDF形式でダウンロード (158K)
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