Analysis of bulk organic explosives for forensic laboratories

Program Code: 

A/Prof Charles Harb (

Description of Work: 


Analysis of bulk organic explosives is a straightforward task for well-equipped forensic laboratories, but it is more difficult for them to analyse trace amounts of organic explosive residues; this usually requires an elaborate sequence of solvent extraction from swabs and some form of chromatographic or electrophoretic separation. Suitable detection techniques include ion mobility spectrometry (IMS), mass spectrometry and thermal energy analysis, however, such analytical systems lack the sensitivity to analyse explosive residues in vapour samples because of the very low vapour pressures. We aim to develop a cavity-enhanced spectroscopic instrument as a high-throughput screening tool for trace explosive detection, and potentially for other threats such as biological or chemical hazards. The method that we shall use to achieve this aim is cavity ringdown spectroscopy (CRDS), which is a laser-based direct-absorption technique. CRDS offers a significant increase in sensitivity, sufficient to permit detection of organic explosives in the vapour phase.

Description of Work:

  • Design and build the CRDS System;
  • Design and build the detection and modulation/demodulation systems;
  • Make measurements on different substances of interest, and catalog the data.
  • Investigate algorithms to pattern match the database with unknown samples.