Detection of explosives - Studies on thermal decomposition patterns of energetic materials by means of chemical and physical sensors

- Proven feasibility of lirary free discrimination between energetic and non-energetic materials.
- Simple experimental setup.
- Potentially time and cost efficient, but still reliable detection of explosives.

The present study investigates the feasibility of library free discrimination between energetic and non-energetic materials, based on the behavior of the substance rather than its chemical composition. This allows the evaluation of explosion hazard even for novel, previously not encountered materials. The setup is designed for solid samples in the lowest milligram range and utilizes rapid heating for thermal activation of the analyte. The reaction is monitored by a pressure sensor, photodiodes and metal oxide semiconductor (MOX) gas sensors. Key features are the application of readily available physical and chemical sensors, utilization of ambient air as a carrier gas, regulation of sample weight by the geometry of the heater and easily understandable read out. The acquired data from physical sensors is analyzed for specific thresholds to separate high reactive energetic materials and propellants. The remaining analytes are investigated with MOX gas sensors in the second step to discriminate less reactive energetic materials from benign ones. The rate of correct assignments for the developed setup is 93,2% with a total of 11 false negatives and 2 false positives out of 190 experiments. For high reactive energetic materials principal component analysis (PCA) shows potential for the identification of the analytes.