| Co-Investigator(Kenkyū-buntansha) |
INOKUCHI Toshio Maruto Ltd.Technical Planning Division Technical Research Advisor, 技術企画室, 研究技術顧問
OGATA Kiyosh Hitachi, Ltd.Materials Process Department Production Engineering Research Labora, 第2部24研, 研究員
KOMATSU Teruhisa The University of Tokyo Ocean Research Institute Research Associate, 海洋研究所, 助手 (60215390)
NAKAI Izumi Science University of Tokyo Department of Applied Chemistry Associate Professor, 理学部, 助教授 (90155648)
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| Research Abstract |
After the investigation for three years, the following results have been obtained.
1.Sample Preparation : Methods of sample preparation for synchrotron radiation X-ray fluorescence microprobe analysis was developed. For the fish otolith preparation, sagaital plane with otolith core of 30mum thick was revealed to be suitable for the analysis.
2.Investigation of finger-print elements : ICP-AES analysis of otoliths of various fishes of different origin disclosed that they contain Sr, Zn, Fe, Mg, Mn and Al as trace components, among which Sr is found to be most suitable for the indicator of the salinity change of their environmental water.
3.Application of Synchrotron Radiation : Two-dimensional distributions of Ca, Sr and Fe were clarified by synchrotron radiation X-ray fluorescence microprobe. Measurements were made at Photon Factory, High Energy Accelerator Research Organization. Samples were excited by an X-ray of 17 keV generated by a Si (111) double-crystal monochromator. Two dimensional analysis of trace elemenls such as iron (average : around 100 ppm) was successfully carried out by using X-ray microbeam under the following condition : beam size, ca 100x1OO um2 and counting time of 10
sec/step. Thus we have established the XRF imaging technique as a new important tool for characterization of the trace elements in the otoliths.
4.Instrumentation : We have developed a new X-ray fluorescence imaging system for routine analysis of the trace elements in the hard tissues by using conventional laboratory X-ray source. This system utilizes monochromatic Mo Ka X-ray obtained by a curved Graphite monochoromator, which enables us to carry out high sensitivity analysis.
5.Validation of the methods : To verify the method developed here, otoliths of the freshwater eel, masu salmon and lantern fish were analyzed. As the results, the individual migratory history was well demonstrated and thus, we conclude this method was sufficiently verified.
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