Detecting Terrorists' Explosive Of Choice

The explosive triacetone triperoxide (TATP) was used in the terrorist bombings on the London subway system in 2005 and by the infamous shoe bomber who tried to detonate his shoes on a trans-Atlantic flight in 2001. Although the explosive is easy to make, its detection has proved to be challenging, says Nathaniel S. Finney, a chemist at the University of Zurich. To remedy the situation, Finney and graduate student Sergey Malashikhin have developed the first fluorescence-based assay for TATP (J. Am. Chem. Soc., DOI: 10.1021/ja802989v). The assay detects the explosive down to 100-nM levels, which is more sensitive than existing colorimetric assays. The researchers first built a series of pyrene-sulfoxide chemical probes (one shown). When TATP is irradiated by UV light, it produces hydrogen peroxide, which interacts with methyltrioxorhenium in the assay to oxidize the nonemissive sulfoxide into a fluorescent sulfone. The researchers are now trying to increase the stability of the fluorophores and decrease the reaction time from an hour to minutes. "The success of this assay suggests the potential for broader application of aryl sulfoxides in fluorescence chemosensing," such as detecting metal ions in the environment, Finney notes.