NCJ Number
191314
Journal
Journal of Forensic Sciences Volume: 46 Issue: 5 Dated: September 2001 Pages: 1053-1069
Date Published
September 2001
Length
17 pages
Annotation
This article examined the use of Raman spectroscopy in the identification and analysis of some of the components of paint, specifically automotive paint pigments.
Abstract
This article examined the applications of Raman spectroscopy in forensic sciences involving the analysis of paints. The paints examined included U.S. automobile original (OEM) finishes (1974 to 1989) from the Reference Collection of Automotive Paints, more recent finishes from paint manufacturers, and paints removed from vehicles. Because Raman data are complimentary to infrared data, infrared spectra were also presented for the pigments and paints and features for both spectra were compared and contrasted. In this study, a dispersive CCD Raman spectrometer (785 nm) was used in a configuration that collected scattered light from an excitation region 3mm long and 80 u.m wide, instead of from a focused spot. Ramon spectra (of light-colored non-metallic finishes) revealed prominent peaks of rutile. The rutile peaks were readily distinguished from those of anatase. In addition, Raman spectroscopy also provided an unequivocal means to distinguish chrome yellow from molybdate orange. Because no sample preparation was required, Ramon spectroscopy provided an excellent means to screen reference panels for the presence of certain pigments and some examples of the differences in Raman spectra that occurred for paints having similar colors were presented. Graphs and references