| Abstrakt: |
In post-blast explosions, only trace amounts of residual explosives are present and their analysis is based on the identification of unreacted explosives. Exhibits from post-blast explosion scenes may be contaminated with interfering materials, thus cleanup procedures have to be used prior to the analysis stage. The type of explosive material involved can greatly assist the intelligence and investigation units in connecting different incidents, in connecting a specific suspect with a crime scene, and in tracking terrorists or other criminal activity. The detection of post-blast high explosives in the Israel Police laboratory is usually performed by extracting the exhibits with organic solvents (mainly acetone) and after evaporation of most of the solvent, injecting the concentrated liquid into a gas chromatography/mass spectrometry (GC/MS) instrument for analysis. A main challenge is that acetone dissolves many other materials such as fatty acids, plastic, oils, and so forth. These materials may be present in large amounts, which may cause a decrease in the resolution or sensitivity in the GC/MS, and, as a result, might screen the target explosive materials. In this paper, we present an effective, simple, and environmentally friendly procedure of extraction of post-blast high explosives using hot water followed by liquid-liquid extraction with a very small amount of organic solvent: dichloromethane. This method has already been successfully tested on dozens of cases received for examination. [ABSTRACT FROM AUTHOR] |
