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Technology Development, Implementation and Evaluation for Collection and Analysis of Explosives Trace Chemical Evidence

NCJ Number
Date Published
August 2000
58 pages

This report describes the development and performance of a method for sampling surfaces to detect the presence of trace amounts of organic explosives.


The goal of this research project was to provide scene investigators and forensic chemists with an alternative method for organic explosives sampling and analysis that does not require the use of solvents. The research has resulted in the development of a dry surface-wipe method of debris sampling that uses abraded Teflon as the sample-collection material. Teflon was identified as the wipe material-of-choice after surveying a number of commercial polymers. The resistance of Teflon to tearing on rough surfaces and edges of debris from a bomb blast and its stability under gentle heating made it the ideal material for this application. For analysis, an innovative approach was developed that involved heating the Teflon wipe to 170 degrees C in the sample inlet of the instrument. This allows the explosive to be removed from the wipe and introduced directly into a conventional gas chromatograph. The method developed uses commercially available polymers and laboratory instruments; it requires only the addition of a single inexpensive valve to the chromatograph's exterior ($20 and 5 minutes to install). Appended published papers on this research

Date Published: August 1, 2000