Ion Mobility Spectrometry (IMS)
In the traditional method of Ion Mobility Spectrometry (IMS), the testing substance is heated and the molecules would gasify before going through a permselective semipermeable membrane and entering the drift tube. Then, those different kinds of molecules would be ionized by ionization source into molecular ion groups, which, under the effect of the electric field in the drift tube, would migrate through the tube to the detector with different speed, produce current pulse in the detector and finally form an Ion Mobility Spectra with migration time as the horizontal axis and current intensity as the vertical axis. As the migration speed is based on the ion’s mass, size and charge, different substances can be distinguished from the peaks in different position in the spectra.
Besides the IMS technology, new orientation including Field Asymmetric Ion Mobility Spectrometry (FAIM) has been developed with the development of technology.
As IMS-based technology inspection methods are featured by its advantages including being able to work under barometric pressure, high detection sensitivity, short analysis time, small size light in weight and low power consumption, it is the most practical trace detection method, which has been applied in various fields such as the detection of narcotics and explosives, testing of chemical warfare agent and monitoring of toxic gas from factories.