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Volume 31 (1997)
- Issue 4 Pages 193-
- Issue 3 Pages 133-
- Issue 2 Pages 69-
- Issue 1 Pages 1-
Volume 31, Issue 3
Displaying 1-6 of 6 articles from this issue
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Review in series “New Approaches to Geochemistry”
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Jun-ichi KIMURA, Nobutaka TSUCHIYA, Sakae SANO, Norichika CHUMAN, Take ...1997 Volume 31 Issue 3 Pages 133-151
Published: August 04, 1997
Released on J-STAGE: December 21, 2016
JOURNAL FREE ACCESSRecent advances in inductively coupled plasma source-mass spectrometry (ICP-MS) has enabled us to determine trace and ultra-trace elements contained in various geochemical samples. Due to the high sensitivity and rapid mass scanning features of ICP-MS, multiple element analysis for trace elements can be performed without any pre-concentration procedure. The high sensitivity also permits direct spot analysis of solid geochemicl samples using laser ablation (LA) or laser probe (LP) sampling techniques. Spatial resolution as fine as 5-15μm has been achieved in the LP system. However, despite the great analytical ability of ICP-MS, some care should be taken in quantitative analyses. Spectroscopic interferences such as oxide molecular ions (MO+), doubly charged ions (M++), and polyatomic ions (i. e., ArX+) affect the accuracy of measurements for the certain elements.Non-spectroscopic interferences, known as the matrix effect, also affect the analytical accuracy. There are two causes of the matrix effect: one originates in the plasma equilibrium and the other is the mass discrimination effect in an ion beam known as the "space charge effect". Differences in both the major chemical composition and introduction volume of analyte shift the aspect of the matrix effect. In order to attain high precision and accuracy in the analysis, optimization of the facility setting and analytical procedure is required to minimize those interferences. The problem in LA analysis is elemental fractionation mainly due to thermal heating of the sampling site during the laser ablation. This paper presents the facilities, functions, and analytical techniques of ICP-MS. Actual examples of terrestrial water analysis, rock analysis using solution samples, and micro analysis of minerals and bulk-rock analysis using LA-ICP-MS are also presented in this paper.View full abstractDownload PDF (2054K)
Review
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Hodaka KAWAHATA1997 Volume 31 Issue 3 Pages 153-162
Published: August 04, 1997
Released on J-STAGE: December 21, 2016
JOURNAL FREE ACCESSVariations in the ocean's carbon system through time are of fundamental interest for chemical oceanography and paleoclimatology. Since the North Pacific (NP) contributes more than 25% of the world ocean volume, variations in the NP Ocean system may have profound effects in redistributing carbon within the world ocean, which eventually causes the variations of the ocean-atmosphere carbon flux. However, paleoceanographic studies in the high-latitude NP have less progressed than those in the North Atlantic. A benthic δ13C record from high latitude NP sediments suggests that the ventilation of the deep Pacific would have actually been decreased during glacial times. In contrast, seismic reflection profiles and occurrence of oxidized brown clays suggest enhanced advection of Antarctic bottom water or formation of deep water locally in the NP during glacial periods. Benthic δ13C patterns at Pacific intermediate water core sites are contradictory with regard to changes in the intermediate circulation of the Pacific. The NP benthic δ13C record suggests that the NP deep water were continuously more corrosive to carbonate than deep waters in the North Atlantic. However, carbonate deposition at the deep NP core sites was enhanced during glacial times. This paradox may be explained by an increase in alkalinity in the global NP deep water.View full abstractDownload PDF (1148K)
Original Paper
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Yoshio ISHIKAWA, Yoshimi SUZUKI, Tetsuo HIRAGA1997 Volume 31 Issue 3 Pages 163-170
Published: August 04, 1997
Released on J-STAGE: December 21, 2016
JOURNAL FREE ACCESSThe carbonate chemistry plays an important role in the carbon cycle, but still not specified quantitatively. To know the change and cycle of calcium concentration is essential to the oceanic carbonate chemistry. A high precision titration method using Zincon indicator reagent and an autooptical sensor was used for the determination of concentration of calcium in sea water. The optimal conditions for the determination was examined. It was found that for the highest precision titration, better than ± 0.05% for 10.20mmol Ca l-1 in sea water, the best pH is 9.76 to 9.84 and the amount of Zincon is 0.5 to 0.7ml. The end point of this method was determined by an optical sensor with a filter of 620nm. This method was applied to sea water samples taken around a coral reef in Miyako Island. The temporal change of calcium concentration was observed to range from 9.98 to 10.2 mmol Ca l-1. The lower concentration of calcium in coral reef waters was found during day time. It was confirmed that the present method provides precise data of calcium concentration in sea water.View full abstractDownload PDF (794K) -
Yasuhiro SUZUKI, Seiya NAGAO, Yuzuru NAKAGUCHI, Takeshi MATSUNAGA, Sus ...1997 Volume 31 Issue 3 Pages 171-180
Published: August 04, 1997
Released on J-STAGE: December 21, 2016
JOURNAL FREE ACCESSThe spectroscopic properties of fluorescent substances in the waters samples collected from the Kuji River system were investigated by three-dimensional excitation emission matrix (3-DEEM) spectroscopy without concentration. The river water samples were collected at seven sites in the Kuji River and at three sites in the tributary rivers. The 3-D EEM spectra were characterized by two broad excitaion/emission maxima at excitation (Ex.) 220±5/emission (Em.) 425±15nm and Ex. 325±10/Em. 430±15nm. The peak positions of excitation/emission maxima and peak height ratios in the water samples were in good agreement with those of soil fulvic acid extracted from the Ando soil, which is distributed in the Kuji River basin from the middle stream to the lower stream. The results suggest that fluorescent substances in the Kuji River waters mainly consist of fulvic-like substances which are supplied from the basin of the river system.View full abstractDownload PDF (992K) -
Takashi KASAMATSU, Takeo KANEKO, Takeshi SAITO, Kensei KOBAYASHI1997 Volume 31 Issue 3 Pages 181-191
Published: August 04, 1997
Released on J-STAGE: December 21, 2016
JOURNAL FREE ACCESSAbiotic formation of amino acid precursors in ice mantles of interstellar dusts was quantitatively estimated for the first time through laboratory simulation. Mixtures of carbon monoxide (or methane, or methanol), ammonia and water were irradiated with protons, electrons or gamma-ray. Amino acid precursors, which gave amino acids such as glycine after acid-hydrolysis, were detected in each product. Using the G-values of glycine experimentally obtained, G-value of glycine in ice mantles of interstellar dusts, whose major components were water, carbon monoxide and ammonia (100:10:1) was estimated as ca. 6×10-6. It is suggested that comets, aggregates of interstellar dusts, contain ca. 20nmol/cm3 of glycine precursors. Bioorganic compounds delivered to the primitive earth by comets or their fragments (interplanetary dusts) are quite important sources for building blocks of the first life on earth, as well as endogenous bioorganic compounds.View full abstractDownload PDF (1002K)
Abstract of doctoral thesis
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Naomi Harada1997 Volume 31 Issue 3 Pages 192-
Published: August 04, 1997
Released on J-STAGE: December 21, 2016
JOURNAL FREE ACCESSDownload PDF (165K)
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