Rapid and selective detection of explosives has become one of the most pressing issues concerning homeland security, military applications, forensic investigations, and mine-field analysis. Tons of explosives are found in many unexploded land mines worldwide. Nitro-aromatics such as 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (2,4-DNT), and 2,4,6-trinitrophenol (TNP) are common ingredients of industrial explosives which have contaminated soil and groundwater at large. Hence, the detection of nitro-aromatics present in soil and groundwater is very crucial for environmental monitoring near ordnance bases. Trinitrotoluene (TNT), Trinitrophenol (TNP or picric acid), and Dinitrotoluene (DNT) are all nearly related chemical compounds with different vapor pressures and volatility, which can be investigated by headspace analysis and direct injection using zNose®. This technical paper covers topics such as:

• Direct injection method to detect TCA

• Analysing chemistry of TNT vapors at room temperature

• Comparison of direct injection and headspace vapors