Discrimination of new and aged post-blast explosives residues

The main objective of this project is to study the difference between aged and un-aged post-blast residues and nonblasted explosives. Sand from the post-blast scenes was subjected to accelerated aging (temperature, light and addition of water) over a period of 20 weeks. The samples were aged as matrix-free pure compounds and as post-blast sand. Several explosive materials were detonated over sand-filled containers and selected residues were separated and detected with HPLC/UV. Separation and detection methods using GC/MS and LC/UV were developed. This screening study of aged post-blast residues revealed that most of the residues reached low or undetectable concentration within a period of eight weeks of aging. This degradation rate theory can be applied both for the temperature- and UV-aged samples. The half-life degradation time (t 1/2 ) was estimated and most of the detected residues reach t 1/2 within five weeks. No trends with significant difference can be seen between the UV- and temperature-aged samples.