NCJ Number
226892
Journal
Journal of Forensic Sciences Volume: 54 Issue: 3 Dated: May 2009 Pages: 564-570
Date Published
May 2009
Length
7 pages
Annotation
This study used high-energy synchrotron radiation x-ray fluorescence spectrometry (SR-XRF), with 116 keV x-rays, in order to characterize titanium dioxide (TiO2) pigments (rutile) and automotive white paint fragments for forensic examination.
Abstract
The trace elements derived from TiO2 pigments were useful indicators for characterizing finish coat layers of automotive white paint fragments. This technique allowed for the analysis of K lines of 9 trace elements in 18 titanium dioxide pigments and 10 trace elements in finish coat layers of 7 automotive white paint fragments. 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 distinguished by this technique. High-energy SR-XRF has advantages for the analysis of a greater number of elements, including heavy elements in the energy region above 20 keV with good sensitivity. The sample size necessary for this technique is as small as 0.1 mm x 0.1 mm, which is particularly useful for forensic identification. The 18 TiO2 pigments with a rutile structure, which had been produced by either the sulfuric acid method or the chlorine method, were obtained from the pigment manufacturers. Fragments of seven automotive white paints produced by three manufacturers were taken from the vehicles involved in accidents. In order to compare finish coat layers by the portions of the binders and the pigments, Fourier transform-infrared spectroscopy (FT-IR) analysis was performed. The sample preparation for high-energy SR-XRF analysis is described along with the features and procedures of the system used. 3 tables, 6 figures, and 29 references