Modular Ion Mobility Spectrometer for Explosives Detection Using Corona Ionization

Abstract

Ion mobility spectrometry (IMS) has become the most widely used technology for trace explosives detection. A key task in designing IMS systems is to balance the explosives detection performance with size, weight, cost, and safety of the instrument. Commercial instruments are, by and large, equipped with radioactive (63)Ni ionization sources which pose inherent problems for transportation, safety, and waste disposal regulation. An alternative to a radioactive source is a corona discharge ionization source, which offers the benefits of simplicity, stability, and sensitivity without the regulatory problems. An IMS system was designed and built based on modeling and simulation with the goal to achieve a lightweight modular design that offered high performance for the detection of trace explosives using a corona ionization source. Modeling and simulations were used to investigate design alternatives and optimize parameters. Simulated spectra were obtained for 2,4,6-trinitrotoluene (TNT) and cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX) and showed good agreement with experimentally measured spectra using a corona ionization source. The reduced mobilities for TNT and RDX obtained with corona ionization were 1.53 and 1.46 cm(2)/(V s), respectively, and this agreed well with literature values.

A novel driving mode for ion shutter based on alternating current superposition and its application to ion mobility spectrometry

“…The reduced ion mobility of RDX ions under the C 1 and C 2 driving modes were calculated as 1.48 cm 2 V −1 s −1 and 1.44 cm2 V −1 s −1 , respectively, which are very close to the reported values of 1.47 cm 2 V −1 s −1 [21], 1.46 cm 2 V −1 s −1 [22] as measured by corona discharge IMS.…”

Broadscale resolving power performance of a high precision uniform field ion mobility-mass spectrometer

“…Taken collectively, these observations suggest that the present instrumentation performs at optimal resolving power for a wide dynamic range of ion species under similar operational conditions. This may be a general observation for all ion mobility instrumentation, as quantitative investigations of the conditional resolving power to date have focused only on small analytes with reduced mobility values greater than 1.2 cm 2 /V·s, 13,18,31,32 although this study also represents the first test of conditional resolving power theory for reduced pressure IMS, so these results may also be specific to sub-ambient pressure operation around 4 Torr.…”

Computational fluid dynamics-Monte Carlo method for calculation of the ion trajectories and applications in ion mobility spectrometry

“…With the development of computer technology and simulation technique, many simulation models have been developed to describe the ion motion in electric field [33][34][35][36] or gas flow field [37,38], separately. Some simulation packages also have been developed, such as ITSIM [9,[39][40][41], GEMIOS [42,43], microDMX [44] and SIMION [45] for the ion trajectory simulation.…”