土砂の法科学分析のためのレーザーアブレーションICP-MSによる火山ガラスの微量元素分析

The purpose of the present study is to develop a new method for forensic soil analysis by focusing trace element composition of volcanic glass in a soil determined by LA-ICP-MS. First, we have established the LA-ICP-MS analysis of trace-element compositions of the volcanic glass originated from the typical 8 tephra distributed in Japan. We succeeded in discriminating all tephra samples without ambiguity by applying linear discriminant analysis using 6 trace-element compositions of the analyzed volcanic glass shards. Finally, as a case-study experiment, we conducted forensic comparisons of soil samples collected in a certain forest in Japan (Sample A) and those collected in the car (Sample B) used for the collection process of Sample A. According to the trace element analysis of the volcanic glasses contained in each samples, it was estimated that both samples have the same origin. From these observations, we have demonstrated that volcanic glass can be a useful index for soil identification in Japan and LA-ICP-MS analysis is appropriate for this purpose.