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Volume 42, Issue 1
Displaying 1-3 of 3 articles from this issue
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REGULAR PAPERS
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Yasuhide NAITO, Masao INOUE1994 Volume 42 Issue 1 Pages 1-9
Published: 1994
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSWhen two ions with very small mass difference are analyzed by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry, the two peaks in the mass spectrum approach to each other by increasing the number of ions and finally merge into a single peak, even though the width of the peaks is sufficiently small compared to the distance between the peaks. It seems that Coulomb force between the two ion packets modulates their cyclotron motions produced by an rf electric field in the FT-ICR trap. We studied the phenomenon theoretically using a model of two charged particles which are confined in a plane perpendicular to a uniform magnetic field. In the case that the two ions appear as a single peak the two ion packets are coupled and rotate around the center of mass with oscillating radius and the position of the peak in the spectrum is determined by the frequency of rotation of the center of mass which corresponds to the weighted average of the mass of the two ion packets. It is found that there is an oscillating force acting between the two ion packets and when the force is resonant with the oscillating radius, the two ion packets are decoupled and appears as two separate peaks in the spectrum. Various factors which affect the phenomenon are discussed.View full abstractDownload PDF (514K) -
Naoki ASAKAWA, Hiroshi OHE, Yoshiya ODA, Nariyasu MANO, Yasushi SHIKAT ...1994 Volume 42 Issue 1 Pages 25-33
Published: 1994
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSIn the combination of liquid chromatography (LC)-fast atom bombardment mass spectrometry (FABMS), a new frit postcolumn addition of matrix (frit-PAM) system was designed to overcome the problems such as the diffusion of analytes and the ineffective ionization on FAB probe under the slow mobile phase flow. This system had a coaxial flow of LC effluent and FAB matrix in two separate tubes, and a frit to mix the both flows. The potential of this system was explored in the Frit-FAB LC/MS analysis of the tryptic digest of lysozyme as a test sample. This system can allow to use the mobile phases for the optimum separation in LC and the FAB matrix solution for the optimum ionization of analytes in FABMS, respectively, and can provide a high sensitivity.View full abstractDownload PDF (550K)
TECHNICAL REPORT
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Keisuke NAGAO, Tsuyoshi ABE1994 Volume 42 Issue 1 Pages 35-48
Published: 1994
Released on J-STAGE: July 20, 2007
JOURNAL FREE ACCESSA pulse Nd-YAG laser was applied to noble gas extraction from a small portion of primitive meteorite, Allende. Details of experimental methods using the laser microprobe have been described. The laser could make through-holes with diameters of 300 and 130μm by about 40 pulses with energy of 300 and 90 mJ/pulse in aperture-out and -in modes, respectively, in a thin plate of the Allende meteorite, 0.8 mm thick. Weights of fused material were estimated to be 200 and 40 μg for the pits produced in the aperture-out and -in modes, respectively, by approximating a cylindrical shape to the laser pits and the density of 3.5 g/cm3. The calculated noble gas compositions were compared with the reported values to examine outgassing efficiencies for noble gas elements from the laser pits. Heterogeneous distributions of radiogenic noble gases, 4He, 40Ar, and 129Xe, are compatible with previous observations.View full abstractDownload PDF (971K)
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