Spectroscopy is an important area of research in the search for better
methods to detect explosives. As the quote above mentions, it is becoming
increasingly important to develop technologies which will give authorities
the ability to identify explosives or people who have been near explosives
in order to keep the public safe from these threats.Some major hindrances to the goal of "stand off" detection are outlined below (21):
http://www.chemsoc.org/exemplarchem/entries/2004/
bristol_hook/applications/
Low Vapor PressuresMost explosives have very low vapor pressures at room temperatures. This makes it very difficult to detect explosive particles in the air because very few of the particles will vaporize. It may be necessary to collect very large volumes of air in order to pull in enough of an explosive sample to detect.
Usually Hidden
With the natural tendency to conceal the explosive weapon, even less vapor particles may escape the package as they would likely be trapped inside a complex container.
Interference
Some explosives may have a chemical signature resulting from common components used to create them. These common materials may lead to false positives.
Spectroscopic methods are already used in identifying explosives. Current research is attempting to improve methods to decrease the necessary sample size and to allow for non-contact sampling. (20,21) Though FTIR and Raman have succeeded in detecting explosives in trace amounts, this has only occurred when the samples are on a surface. The weak Raman effect makes it very difficult to consider this method for vapor sampling where SERS cannot be used. Small portable Raman devices, however, still make it a viable resource for detecting explosives in certain situations and for studying the scene of a crime after the explosion occurred. (22)
