Whether it’s an airport screening station or in-the-field terrorism investigations, trace detection of explosives – which are chemical compounds – generally involves the collection of vapor or particulate samples from these chemicals and analyzing them using a sensitive sensor system.
Explosive trace detection (ETD) is a challenging task. As the name suggests, ‘trace’ refers to quantities of materials difficult to see with the naked eye. In ETD, this quantity can be considered to be < 1mg.
Various factors, such as wide variety of compounds that can be used as explosives, the vast number of deployment means, and the lack of inexpensive sensors providing both high sensitivity and selectivity, have made trace detection a complex and costly task.
Source: Nano Werk