Vapor Detection of TNT and RDX Using Atmospheric Pressure Chemical Ionization Mass Spectrometry with Counter-Flow Introduction(CFI).

Abstract

To enable vapor detection of TNT and RDX, we have combined atmospheric pressure chemical ionization (APCI) mass spectrometry with counter-flow introduction (CFI) of sample vapors. The chemical ionization source, which enables high ionization efficiency and highly selective ionization, was attached to a quadrupole mass spectrometer. Using this modified mass spectrometer, we obtained negative mass spectra and detection chromatograms of trinitrotoluene (TNT) and 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) vapors at room temperature. The explosives detection could be done within 5 s. Our test results from this prototype system demonstrate that this technique is suitable for practical on-line explosives detection.