NCJ Number
211275
Journal
Journal of Forensic Sciences Volume: 50 Issue: 5 Dated: September 2005 Pages: 1028-1038
Date Published
September 2005
Length
11 pages
Annotation
This collaborative study evaluated the use of Raman spectroscopy on colored fibers and on dye powders to determine the quality of the spectra obtained.
Abstract
Raman spectroscopy has already been applied in different types of forensic science samples, such as inks, automotive paints, drugs, lipsticks, and explosives. In this collaborative study from the European Fibres Group (EFG) (considered one of the largest studies ever done on colored fibers and dye powders), Raman spectra were recorded with nine different laser sources to observe the influence of the excitation wavelength on the spectral quality of colored fibers and dye powders. The evaluation consisted of nine dye powders and three colored fibers (two red acrylics and one red wool). Raman instruments from six different manufacturers were tested as well as nine different laser wavelengths ranging from blue to near infrared. The results indicate that red laser at 633 and 685 nm very often showed fluorescence problems and they could not be recommended for this sample set. Blue (458 nm), green (514 nm), and near infrared lasers (785, 830 and 1064 nm) provided average results. However, blue (488 nm) and green lasers (532 nm) globally gave the best quality spectra. Globally, Raman spectroscopy enabled the identification of the main dye present in a fiber sample given that the spectrum obtained was of good quality (no fluorescence) and the corresponding dye spectra was available. In addition, SERRS or Surface Enhanced Resonance Raman Scattering techniques gave an improvement of the dye’s spectral intensity. However, no spectral improvement was seen for the two red acrylic and red wool fibers tested. Tables, figures, and references