Trace explosives sampling for security applications (TESSA) study: Evaluation of procedures and methodology for...

Area of Science:

• Forensic Science
• Analytical Chemistry
• Materials Science

Background:

• Trace explosive detection is crucial for security in high-traffic areas like airports and train stations.
• Current screening methods rely on collecting particulate residue using traps, but residue collection is a bottleneck.
• Standardized evaluation of sampling media is needed to improve explosive detection efficiency.

Purpose of the Study:

• To establish a standardized methodology for evaluating the collection efficiencies of different sampling media.
• To compare the performance of various traps in collecting explosive residues from different surfaces.
• To identify factors influencing the efficiency of contact sampling for explosive detection.

Main Methods:

• A multi-institutional study was conducted using standardized testing parameters.
• Dry residues of RDX, C-4, and PETN were collected from ABS plastic, ballistic nylon, and aluminum surfaces.
• Muslin, Texwipe cotton, and stainless-steel mesh traps were used, with analysis via liquid chromatography-mass spectrometry.

Main Results:

• Dry transfer efficiencies (DTE%) to surfaces exceeded 75%, with ABS plastic showing the lowest transfer.
• Collection efficiencies (CE%) varied significantly; nylon surfaces yielded the lowest CE% (approx. 10%).
• Stainless steel mesh traps exhibited the lowest CE% among the tested traps (approx. 20%).

Conclusions:

• Sampling media and surface material significantly impact the collection efficiency of explosive residues.
• Nylon surfaces and stainless steel mesh traps are less effective for collecting explosive residues.
• Further research is needed to understand and mitigate variables affecting contact sampling efficiency for improved explosive detection.