An Ion Gating Strategy for a Miniaturized Planar Ion Mobility Spectrometer

In Ion Mobility Spectrometry, the identities of charged species are determined by measuring their mobility in an electric field and comparing the results to an established database. The charged species may be from a toxin, drug, or organic compound. Measurements are made on small packets of ions, since measurements on a continuous stream of ions does not provide drift time information. The performance of an Ion Mobility Spectrometer is largely determined by the effectiveness of the ion gating technique and the ability to emit and block ions from entering the drift region. A miniaturized version of an Ion Mobility Spectrometer is more easily integrated with other microfluidic devices and would be useful in portable applications. However, a customized gating strategy is required that is compatible with the design and fabrication of these miniaturized devices. This work examines a gating strategy and counter-electrode configuration for a 'planar-type' Ion Mobility Spectrometer with an electrospray ionization source. Numerical modeling and device testing confirms the static operation of the proposed strategy. Applications of Ion Mobility Spectrometry are in health care, biotechnology, and security.