| Research Abstract |
We have studied for distribution and behavior siderophile and chalcophle elements in the mantle. For this purpose, we have developed : (1)new analytical methods for determination of platinum group elements (PGEs) ; (2)the new analytical methods for siderophile, chalcophile and lithophile elements except for PGEs ; (3)the new analytical method for precise determination of Re and Os isotope ratios for application to Re-Os isotope systematics.
We first developed the new sample digestion method for determination of PGEs. In this study, we have designed an utterly new digestion vessel, which is cheap, simple and applicable up to 300C. We have proposed the patent. If this patent is accepted, this will be used all over the world, although the patent was just proposed in Japan, because of the lack of money. There was a reply from the Japanese Patent Office, and we replied and modified the patent.
We also developed the new determination method for Bi,Tl,In,Li,Be,Rb,Sr,Y,Cs,Ba,La,Ce,Pr,Nd,Eu,Gd,Tb
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,Dy,Ho,Er,Tm,Yb,Lu,Pb,Th and U using Q-pole type ICP-MS (ICP-QMS). We developed isotope-dilution internal standardization method (ID-IS). In this method, when the sample is digested with Sm spike, then, the elemental analysis is performed without knowing the exact dilution factor. We developed pseudo-FI method, in which only 0.1mL of sample solution is required for determination of these elements. Furthermore, we developed the determination method for Na,Mg,Al,P,Ca,V,Mn,Fe,Co,K,Sc,Ni,Cu,Zn and Ga using the same sample solution by sector type ICP-MS (ICP-SFMS). These methods are submitted to Geostandards and Geoanalytical Research. In addition, precise determination methods for B,Ti,Zr,Nb,Mo,Sn,Sb,Hf and Ta using ID-IS and pseudo-FI methods by ICP-QMS and ICP-SFMS were developed and submitted.
We also developed new analytical methods for Re and Os isotope analysis using multiple collector ICP-MS (MC-ICP-MS). In this study, Os and Re of <1pg can be measured precisely, which can only be achieved by N-TIMS. This study has been accepted Analytical Chemistry (in press).
Unfortunately, the development of analytical technique required far longer time than we had expected, thus the analysis of mantle samples are in future. Although, we have developed analytical methods, application will not take long time to accomplish. Less
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