Publications Details
Control of the reactant ion chemistry for the analysis of explosives by ion mobility spectroscopy
Changes in the reactant ion composition in the ion mobility spectrometer (IMS) can result in a change in the ionization processes occurring in the ionization region, ultimately leading to an altered instrumental response for the analyte, and exacerbating the problem of qualitative and quantitative analysis. Some species are very susceptible to changes in reactant ions, while other species are relatively unaffected. These types of behavior are observed for two common explosives, namely, hexahydro-1,3,5-trinitrol,3,5-triazine (RDX) and 1,3,5-trinitrotoluene (TNT), respectively. To control the reactant ion composition, and hence the gas phase chemistry, it is necessary to control the composition of gases present in the ionization region of the IMS. A series of modifications are described for the PCP Phemto-Chem 100 IMS that afford the requisite control. The effectiveness of these modifications for analysis of RDX and TNT are described and contrasted with that observed for the unmodified system.