Determination of the concentration of explosives in air by isotope dilution analysis

The concentrations in air of dinitrotoluene (DNT), trinitrotoluene (TNT), nitroglycerin (NG), ethylene glycol dinitrate (EGDN), and pentaerythritol tetranitrate (PETN) were measured at 25 degrees C under equilibrium conditions, and that of cyclomethylene trinitramine (RDX) was measured at elevated temperature by means of an isotope dilution technique. Isotopically multi-labeled compounds were synthesized and used as diluents. Field ionization mass spectrometry was used to measure the abundance ratios of the unlabeled materials. The concentrations in air at 25 degrees C of DNT, TNT, NG, EDGN, PETN, and RDX are 184, 4, 31, 37,000, 7, and 0.8 ppb v/v, respectively. The data obtained may be used for the assessment of the required sensitivity of air-monitoring detection systems.