Vol.9 No.2 2016

Research paper : Development and utilization of geochemical reference materials (T. OKAI)−63−Synthesiology - English edition Vol.9 No.2 (2016) situation, the first samples, G-1 and W-1, were analyzed globally and a large amount of data was collected. The values were determined at a global research level. In addition, the number of geochemical reference materials was small at that time, and these materials were analyzed globally immediately after issuance. In other words, during that time, a large number of global-level analytical values could be obtained from reference materials based on rocks in Japan that were released to the research community. Based on the thinking of current reference material development, this may seem strange. However, in the initial stage, sample preparation and the assigning of values had large research and developmental importance, and these goals were established as the main target. In addition, the rocks that constitute a country (types and chemical compositions) are different for each country, and the necessity and priority of each rock type were also different; therefore, to prioritize the preparation of samples necessary for research and development domestically, it was desirable to make the samples in Japan. It was much easier to obtain materials produced within the country rather than having to import materials from foreign countries, and it was meaningful to promote their use in Japan and raise the standard of analytical techniques.3.1.2 Basic conceptThe first problem to be considered was the rock types for which reference materials should be prepared. The intentions of the manufacturing organization are normally reflected strongly in this selection. In reference to the preceding significance, the basic concept determined was that the first rock types to be prepared should be “rocks that represent Japan.” This decision also had practical significance because the rocks that represent Japan were well represented in geological research documents (petrological descriptions, geological ages, chemical analyses, etc.) and many studies and analyses had been conducted. Consequently, these materials had many opportunities to be used for research, and the prepared reference materials would be used frequently; thus, good analytical values could be collected more easily and the use of the reference materials would be widespread.3.1.3 Examination of underlying technologies and strengths of GSJThe necessary technologies underlying the preparation of reference materials are roughly divided into sample selection, grinding methods, and standard value determination methods (described in Chapter 4). The advantages of GSJ for these underlying technologies and the development of reference materials are shown in Fig. 3. Understanding the need is the most important aspect for selecting samples, and reference materials are prepared by geochemical researchers who need them the most. In addition, because there were notable researchers in each field regarding various types of geological materials, an environment for making the best choices was established, and this included the perspective of using rocks that represent Japan. Because GSJ is the geological survey organization representing Japan, it was able to secure a variety of types of samples domestically. Rocks that represent Japan exist in significant abundance, so there was no problem securing necessary amounts of samples. In addition, the chemical analysis technology of GSJ that existed at the time was highly appraised worldwide, therefore, the initial analytical value (analyzed by GSJ) when reference materials were prepared and distributed was highly reliable and believed to contribute to the further utilization of reference materials.3.2 Evaluation and development of reference materials3.2.1 Japan’s first geochemical reference materialsWith the basic concept and the advantages of GSJ described above, the development of geochemical reference materials began in Japan in 1964 (research topic: “study of geochemical reference material”), and the first two reference materials, JG-1 (1967, granodiorite, Sori, Gunma Prefecture) and JB-1 (1968, basalt, Sasebo, Nagasaki Prefecture), were prepared. Fig. 3 Underlying technology for geochemical reference materials and strengths of GSJ Accurate evaluationHigh reliability of initial analytical valuesVarious types of samples can be obtained domesticallySelection of rocks that represent JapanSample selection based on needThere is accurate chemical analysis technologyGeological survey organization to represent the nationThere are researchers who represent Japan in each field relevant to the various geological samplesPrepared by geochemists who are also users3. Standard value determination method (publication method for data)2. Grinding method (preventing contamination)1. Sample selectionElements to be examined for preparationStrengths of GSJ (characteristics)・What type of rock should be used?・Which area should the sample to be used be collected from? (securing necessary amount)


page 7