Amazing trace: Tracking nerve agent attacksNew approach to chemical testing could help track down terrorists who use chemical agents or explosives
By Doug Page
Government scientists are reporting development of a unique tracking technology that could help law enforcement officials trace the residues from terrorist attacks involving nerve gas and other chemical agents back to the companies or other sources where the perpetrators obtained ingredients for the agent.
The development, from the Pacific Northwest National Laboratory, could one day help track down perpetrators of nerve agent attacks.
Called impurity profiling, the technique identifies impurities in chemical agents like sarin at a crime scene and matches them to the impurities in the source chemicals, pinpointing the likely source. The researchers found that up to 88 percent of the impurities in source chemicals used to make sarin can wind up in the finished product, and that these impurities are unique, like fingerprints.
The technique requires only standard laboratory gas chromatography/mass spectrometry instruments to perform impurity profiling.
“This means potentially tracing a chemical threat agent like sarin to the specific lot number and commercial manufacturer that produced the precursor used to make the sarin collected from a crime scene,” said PNNL chemist Carlos Fraga.
Even though sarin is made by only three North American chemical manufacturers, and then not often, Fraga said that this new piece of evidence could provide useful leads that complement those obtained by traditional crime-scene evidence like latent fingerprints, trace DNA and camera footage.
Previously, there has been no practical way of tracing a chemical agent back to its source ingredients, even though traces of these agents remain after such attacks.
Fraga said that what’s most remarkable is that the chemical impurity profiles can be recovered mostly intact from the sarin samples, even after multiple processing procedures, such as distillation and two solvent-extraction steps.
Fraga told Homeland1 he hopes that this and similar work will deter future chemical attacks by letting terrorists know there are now ways to track them down.
“Second, by developing a forensic capability, we have a greater chance of finding perpetrators of chemical attacks or their sources of materials before they can strike again,” he said.
“And third, our work can potentially be applied to other chemical threats such as illicit drugs and homemade explosives.”