Development of an analytical strategy for the determination of 228Th and 232Th in ivory based on the combined use of ICP-MS and α-spectrometry
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Elephants are endangered due to the value of their ivory tusks. Therefore, a reliable method for age determination of ivory is of interest for the law enforcement against elephant poachers. The ratio of the specific activities 228Th/232Th can be used for the age assessment of ivory. In this report, the combination of two complementary detection techniques, namely inductively coupled plasma-mass spectrometry (ICP-MS) and α-spectrometry, for the determination of 228Th and 232Th in ivory is presented. Using ICP-MS in addition to α-spectrometry, the uncertainty of the 232Th determination could be reduced significantly which enabled a more accurate and effective ivory dating.
KeywordsIvory dating Thorium radioisotopes Inductively coupled plasma mass spectrometry α-spectrometry
The authors thank the zoological garden of Wuppertal and the German Federal Agency for Nature Conversation, which supported this work with ivory samples.
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