Trace Elemental Analysis of Titanium Dioxide Pigments and Automotive White Paint Fragments for Forensic Examination Using High-Energy Synchrotron Radiation X-Ray Fluorescence Spectrometry
High-energy synchrotron radiation x-ray fluorescence spectrometry (SR-XRF) utilizing 116 keV x-rays was used to characterize titanium dioxide pigments (rutile) and automotive white paint fragments for forensic examination. The technique allowed analysis of K lines of 9 trace elements in 18 titanium dioxide pigments (rutile), and 10 trace elements in finish coat layers of seven automotive white paint fragments. High-field strength elements (HFSE) were found to strongly reflect the origin of the titanium dioxide (TiO2) pigments, and could be used as effective parameters for discrimination and classification of the pigments and paint fragments. A pairwise comparison of the finish coat layers of seven automotive white paint fragments was performed. The trace elements in the finish coat layers detected by the high-energy SR-XRF were especially effective for identification. By introducing the trace element information of primer and electrocoat layers, all the automotive white paint fragments could be discriminated by this technique.
Keywords: automotive white paint fragments; forensic science; high-energy synchrotron radiation x-ray fluorescence spectrometry; high-field strength elements; titanium dioxide pigments (rutile); trace elements
Document Type: Research Article
Affiliations: 1: Forensic Science Laboratory, Hyogo Prefectural Police Headquarters, 5-4-1 Shimoyamate-dori, Chuo-ku, Kobe, Hyogo 650-8510, Japan. 2: Japan Synchrotron Radiation Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan. 3: Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Sinjuku-ku, Tokyo 162-8601, Japan.
Publication date: May 1, 2009