NCJ Number
227706
Journal
Journal of Forensic Sciences Volume: 54 Issue: 4 Dated: July 2009 Pages: 846-850
Date Published
July 2009
Length
5 pages
Annotation
This paper describes the application of attenuated total reflection (ATR)-Fourier transform infrared (FTIR) spectromicroscopy for the detection of explosive particles in fingerprints.
Abstract
The findings indicate that it is feasible to detect and identify explosive particles in fingerprints by using ATR-FTIR spectromicroscopy. The particles of explosive and fingerprint residues cannot normally be differentiated by their morphology alone; however, their infrared spectra can differentiate between them. Particles as small as 20 mm in fingerprints can be analyzed by the ATR-FTIR spectromicroscope. Although the analyzed particles are pressed by the ATR-FTIR probe, this does not disturb the line pattern of the fingerprint, because the region over which the probe contacts the specimen is much smaller than the width and spacing of the fingerprint lines. The explosive particles can be identified by searching their spectra in an infrared spectral library, in order to find matching spectra of known materials. The particles in the contaminated fingerprints can be a mixture of explosive and finger residue. Any interference from finger residue must be isolated from the spectrum of the explosive before attempting a match in the infrared spectral library. The study examined the fingerprints obtained after depositors had handled three different types of explosives or potential explosives. The substrate used for the fingerprints was stainless steel. The three explosives were trinitrotoluene (TNT), trinitrobenzene (TNB) and ammonium nitrate (AN). Purities were 99 percent or above. 7 figures and 16 references