Vapor Pressure of Linear Nitrate Esters Determined by Transpiration Method in Combination with VO-GC/MS

摘要

Gas phase detection of explosives is an ongoing trend in the detection sciences. The conception of gas phase detection devices requires knowledge about gas phase concentration of the target analytes. Nitrate esters are well performing explosives with a high potential for misuse in improvised explosive devices that need to be detected at vulnerable infrastructures. With respect to this the six nitrate esters, ethyl nitrate (1), ethylene glycol dinitrate (2), glycerol trinitrate (3), meso-erythritol tetranitrate (4), d-mannitol hexanitrate (5) and pentaerythritol tetranitrate (6) were investigated in terms of detectability by vacuum outlet-GC/MS as potential components in improvised explosive devices. All compounds besides 5 could be detected using vacuum outlet GC/MS and their limits of detection were determined according to DIN 32645 : 2008. The vapor pressure of 2-4 was measured using the transpiration method. It was observed that the introduction of a CHONO2 unit lowers the vapor pressure of the nitrate esters by about two orders of magnitude. For compound 4 the saturation concentration (73 ng L-1) was compared with a vapor pressure based estimation of its concentration in diffusion equilibrium (0.385 pg L-1).