Advanced explosives detector sniffs out previously undetectable amounts of TNT

Yushan Yan and colleagues point out that TNT and other conventional explosives are the mainstays of terrorist bombs and the anti-personnel mines that kill or injure more than 15,000 people annually in war-torn countries. In large, open-air environments, such as airports, train stations and minefields, concentrations of these explosives can be vanishingly small -- a few parts of TNT, for instance, per trillion parts of air. That can make it impossible for conventional bomb and mine detectors to detect the explosives and save lives.

They describe development of a preconcentrator that increases the levels of TNT and related explosives by 1,000 times in less than one minute. The scientists made a "molecular sieve" membrane on the surface of holes about as big as a speck of dust. Molecules of explosives get trapped in these holes and concentrated enough that security agents could detect previously undetectable levels of explosives.

The authors acknowledge funding from the National Science Foundation and the China Scholarship Council.