Location and detection of explosive-contaminated human fingerprints on distant targets using standoff laser-induced breakdown spectroscopy

• Explosive remnants left behind by fingerprints have been detected from afar.
• Operating in scanning mode, LIBS boasts high ability to locate traces over a surface.
• Effectiveness in trace detection plainly depends on the scanning spatial resolution.
• The detection capability of LIBS shrinks as the fingerprints deteriorate over time.

Detection of explosive-contaminated human fingerprints constitutes an analytical challenge of high significance in security issues and in forensic sciences. The use of a laser-induced breakdown spectroscopy (LIBS) sensor working at 31 m distance to the target, fitted with 2D scanning capabilities and designed for capturing spectral information from laser-induced plasmas of fingerprints is presented. Distribution chemical maps based on Na and CN emissions are used to locate and detect chloratite, DNT, TNT, RDX and PETN residues that have been deposited on the surface of aluminum and glass substrates. An effectiveness of 100% on fingerprints detection, regardless the substrate scanned, is reached. Environmental factors that affect the prevalence of the fingerprint LIBS response are discussed.