Analysis of explosives using corona discharge ionization combined with ion mobility spectrometry–mass spectrometry

Corona discharge ionization combined with ion mobility spectrometry–mass spectrometry (IMS–MS) was utilized to investigate five common explosives: cyclonite (RDX), trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), cyclotetramethylenetetranitramine (HMX), and 2,4-dinitrotoluene (DNT). The MS scan and the selected ion IMS analyses confirmed the identities of the existing ion species and their drift times. The ions observed were RDX·NO3−, TNT−, PETN·NO3−, HMX·NO3−, and DNT−, with average drift times of 6.93ms, 10.20ms, 9.15ms, 12.24ms, 11.30ms, and 8.89ms, respectively. The reduced ion mobility values, determined from a standard curve calculated by linear regression of (normalized drift times)−1 versus literature K0 values, were 2.09, 1.38, 1.55, 1.15, 1.25, and 1.60cm2V−1s−1, respectively. The detection limits were found to be 0.1ng for RDX, 10ng for TNT, 0.5ng for PETN, 5.0ng for HMX, and 10ng for DNT. Simplified chromatograms were observed when nitrogen, as opposed to air, was used as the drift gas, but the detection limits were approximately 10 times worse (i.e., less sensitivity of detection). [Display omitted] •Five explosives were investigated using corona discharge ionization combined with ion mobility spectrometry–mass spectrometry (IMS–MS).•The MS scan and the selected ion IMS analyses confirmed the identities of the existing ion species and their drift times.•The reduced ion mobility values were determined using normalized drift times and literature K0 values.•The detection limits were found to be 0.1–10ng.•When nitrogen, as opposed to air, was used as the drift gas, the detection limits were approximately 10 times worse.