Detecting explosives

We're hearing a lot about Improvised Explosive Devices (IEDs) these days but what are they made from and how can we detect them?

All about TNT?

We're not always looking for trinitrotritoluene (TNT). A lot of the time sniffer dogs searching for landmines are actually detecting other molecules, like DNT (dinitrotoluene) and DNB (dinitrobenzene). DNTs are a regular impurity in TNT, which arise because some of the toluene molecules were not completely nitrated. Because it is a lighter molecule, the vapour pressure of DNT at room temperature is about 20 times that of TNT, so it's much more detectable.