Isn't exactly a new idea.... (Score 1)

This company (http://www.biosensor.se/) has been producing a similar product for a couple of years now. It's used by the German and Australian customs officials for the detection not only of explosives, but also drugs (oh well). The existing tech as used in US airports has a dismal detection rate and also throws out several false positives. If you're going to have a system, then you might at least have one that works.