Advances in the analysis of explosives

During last decades, the forensic opportunity to detect and identify explosives became more and more important both to protect the safety of citizens and to support the investigations against terrorists and organised crime. The analytical chemistry of explosives has a long tradition of spot test and more traditional approaches, such as chromatography, but has also new tools, such as electro-optical ones, allowing both point detection and remote sensing. In this chapter, four spectroscopic laser based techniques are presented highlighting working principles and capabilities in discriminating explosive compounds at trace level, in field operation, locally or remotely. For each techniques, the detection limits and drawbacks are reported in the application to trace sensing. Such electro-optics tools do not aim to replace the traditional laboratory methods, rather to support them in security applications and in narrowing the area under investigation, reducing the number of samples selected for laboratory analysis. More traditional approaches are then presented and discussed to illustrate the latest development with respect to on-site testing, sampling and analysis by chromatography, electrophoresis and mass spectrometry.