All issues
Volume 54 (2006)
- Issue 6 Pages 227-
- Issue 5 Pages 183-
- Issue 4 Pages 127-
- Issue 3 Pages 75-
- Issue 2 Pages 39-
- Issue 1 Pages 1-
Volume 54, Issue 2
Displaying 1-3 of 3 articles from this issue
- |<
- <
- 1
- >
- >|
REGULAR PAPER
-
Mitsuo TAKAYAMA, Masaru TACHIBANA, Takashi UCHIDA, Hironori KAWAMOTO, ...2006 Volume 54 Issue 2 Pages 39-44
Published: 2006
Released on J-STAGE: April 07, 2006
JOURNAL FREE ACCESSIntact soot exhausted from diesel engines from a large cargo ship and from a farm tractor, which work with heavy and light oil respectively, has been analyzed using laser desorption/ionization (LDI) mass spectrometry. Caged carbon clusters (or fullerene family) were detected as molecular ions M+· with relatively intense peaks at m/z 600, 720, and 840 corresponding to C50, C60, and C70, respectively. There were also other even number carbon clusters C2n (n=20-142 or higher). Small carbon clusters Cn (n=7-29) with the magic number n=7, 11, 15, 19, 23, and 27 were also observed in the LDI mass spectra. The LDI mass spectra of a fullerene C60 (99%) and intact soot showed definite metastable ion peaks originating from successive C2 loss from molecular ions. It was confirmed that under the same LDI conditions the laser vaporization of graphite never gives any products of the fullerene family or even number carbon clusters.View full abstractDownload PDF (383K)
NOTE
-
Yuki SUGIURA, Shuichi SHIMMA, Mitsutoshi SETOU2006 Volume 54 Issue 2 Pages 45-48
Published: 2006
Released on J-STAGE: April 07, 2006
JOURNAL FREE ACCESSDirect tissue analysis and imaging using mass spectrometry can extract a mass of information directly from complex biological samples. To carry out successful profiling and mapping of biomolecules, though, techniques for correct sample preparation are required. This article focuses on the influences of tissue thickness on mass spectra. We obtained the mass spectra and imaging results as a function of thickness from 2 to 40 μm, then evaluated the spectrum quality. The peak intensity and number of observed peaks drastically increased as the sections became thinner (<10 μm). Significant images of high molecular weight proteins were acquired only from the thinner slices. We thus concluded that the thickness of biological tissue slices was an important factor in obtaining high quality mass spectra. There could be two reasons for inefficient analyte ionization of thicker slices: electrical nonconductive properties and impurities in thick tissue sections. In conclusion, this investigation extends the capability of imaging mass spectrometry, especially for high molecular weight protein imaging, by optimizing the thickness of the tissue samples.View full abstractDownload PDF (685K)
TECHNICAL REPORT
-
Chiyomi NAKAO, Keiji GAMOH, Katsumi HISHIDA, Hiroo WADA2006 Volume 54 Issue 2 Pages 49-56
Published: 2006
Released on J-STAGE: April 07, 2006
JOURNAL FREE ACCESSA technique was developed for ligand-exchange liquid chromatography/mass spectrometry (LC/MS) of mono- and oligosaccharides. A mixture of seven monosaccharides, four disaccharides, and two trisaccharides was successfully analyzed by using an improved ligand-exchange column comprising a semi-rigid styrene-divinylbenzene copolymer-based Ca-type cation-exchange resin (ULTRON PS-80C/10S) in conjunction with electrospray-ionization mass spectrometry (ESI-MS). Water was used as a mobile phase to separate the saccharides within 12 min. The ESI interface was used in negative-ion mode for LC/MS and produced reasonable signals from negative molecular ions ([M-H]-) of the saccharides. The effect of aqueous ammonia used as an additive in the eluent was also examined. The detection sensitivities of the saccharides increased when aqueous ammonia was used as an additive at a concentration of 2 vol%. The effects of separation and ionization parameters, column temperature, and cone voltage on the sensitivity and linearity were examined. Linear plots of peak area versus concentration were obtained for MS detection over the range 5-1000 μM (r2=0.951-0.999) for each saccharide. The detection limits of the target saccharides calculated at a signal-to-noise ratio of 3 ranged from 3.7 to 17.1 ng. The reproducibility of the retention times was 0.66-1.2% and that of the peak areas was 0.96-2.86%. A comparison of these results with those obtained with a normal-phase semimicro aminopropyl column confirmed the usefulness of ligand-exchange LC/MS of mono- and oligosaccharides. The newly developed method was applied in the determination of mono- and oligosaccharides extracted from seaweed and hydrolyzed by a hydrothermal reaction.View full abstractDownload PDF (903K)
- |<
- <
- 1
- >
- >|