Vol.9 No.2 2016

Research paper : Development and utilization of geochemical reference materials (T. OKAI)−61−Synthesiology - English edition Vol.9 No.2 (2016) around the world and are contributing globally to improve the reliability of chemical analyses. 2 Background and history of development2.1 Technological background and history of development during the 1940sIn traditional chemical analysis of geological materials, the wet method is used to separate elements (components) chemically, and gravimetric, volumetric, and colorimetric methods are used for quantification. This method is extremely accurate when such analysis is appropriate, but complex operations are required to separate and quantify elements; thus, the method requires experience and a large investment of time. Under such Fig. 1 Geochemical reference materials published by GSJFrom left: JA-1a, JB-2a, JB-3a, JZn-1, and JCu-1Powdered samples are packed in bottles and distributed.Volcanic rocksJA-1JA-1aJA-2JA-2aJA-3JB-1JB-1aJB-1bJB-2JB-2aJB-3JB-3aJF-1JF-2JG-1JG-1aJG-2JG-2aJG-3JGb-1JGb-2JH-1JP-1JP-2JR-1JR-2JR-3JSy-1Andesite (1982)Andesite (2002)Andesite (1985)Andesite (2013)Andesite (1986)Basalt (1968)Basalt (1984)Basalt (1996)Basalt (1982)Basalt (2004)Basalt (1983)Basalt (2003)Feldspar (1985)Feldspar (1986)Granodiorite (1967)Granodiorite (1984)Granite (1985)Granite (2015)Granodiorite (1986)Gabbro (1983)Gabbro (1991)Hornblende (1992)Dunite (1984)Dunite (2011)Rhyolite (1982)Rhyolite (1983)Rhyolite (1990)Syenite (1993)Sedimentary rocksJLs-1JCp-1JCt-1JDo-1JSl-1JSl-2JCh-1SedimentsJLk-1JSd-1JSd-2JSd-3JSd-4JSd-5JMS-1JMS-2JMS-3Coal fly ash and soilJCFA-1JSO-1JSO-3Ores and mineralsJMn-1JZn-1JZn-2JCu-1Limestone (1987)Coral (1999)Giant Clam (2002)Dolomite (1987)Slate (1988)Slate (1989)Chert (1989)Lake sediment (1987)Stream sediment (1988)Stream sediment (1989)Stream sediment (1989)Stream sediment (2005)Stream sediment (2006)Marine sediment (1999)Marine sediment (2000)Marine sediment (2007)Coal fly ash (1995)Soil (1997)Soil (2009)Manganese nodule (1994)Zinc ore (2000)Zinc ore (2008)Cupper ore (2001)conditions, a method for the analysis of the major components of silicate rocks through spectroscopic analysis (emission analysis) using a DC arc was developed, and the era of instrumental analysis began. Compared to the traditional wet method, which requires experience and a large amount of time, instrumental analysis increased the efficiency of chemical analysis significantly. However, instrumental analysis is fundamentally a comparative analysis of physical quantities such as intensity or absorption of light, and it requires criteria. In addition, for samples with complex elemental compositions, such as geological materials, the effects of existing forms of elements and interference by other elements are significant, which caused some problems. To solve these problems, it is useful to create criteria from natural rocks having the same composition as the samples. Based on this idea, Fairbairn at the Massachusetts Institute of Technology (MIT) led the preparation of reference materials from volcanic rocks, and in 1949, the USGS published two references: G-1(Granite) as the representative reference for acidic rocks with high silicon dioxide content and W-1(Diabase) as the representative for basic rocks with less silicon dioxide.[1]2.2 The world’s first collaborative analysis and evaluationThese two samples were distributed to research institutions, including notable universities and geological surveys (GS) around the world, and collaborative analysis was conducted to decide the standard values for the reference. This was an important effort in the sense that it was the first international collaborative analysis of geological materials using common samples. The results of the collaborative analysis, which were reported by Fairbairn et al. in 1951,[2] were shocking. Despite the fact that those who participated in the collaborative analysis were top analysts with first-class techniques from the various countries, the results were not as consistent as predicted. The analytical results for silicon dioxide in G-1 and W-1 are shown in Fig. 2. The differences among the reported results were too large, so a standard value for instrumental analysis could not be decided. The cause for these large differences was that differences among analytical methods were too significant, which thus resulted in a new challenge: the improvement of analytical methods. Subsequently, studies to improve analytical methods were conducted around the world, and finally, in the early 1960s, the desired standard value (recommended value) was reported.[3][4][5] In addition to improvements in analytical methods for major components using the same samples, the development of analytical methods for trace components was actively pursued. The analysis of trace components is strongly affected by major components; however, because collaborative analysis had accurately determined the values of the major components, these samples became ideal materials for examination of trace component analysis worldwide. Furthermore, to establish a standard, many reported analytical values must be compiled. Statistical Table 1. Geochemical reference materials published by GSJ


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