Reducing False Alarms in Ion Mobility Spectrometry Detectors: Determination of Accurate and Precise Reduced Mobility Values
Technical Report,01 Sep 2012,30 Sep 2017
ARMY EDGEWOOD CHEMICAL BIOLOGICAL CENTER APG MD ABERDEEN PROVING GROUND United States
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Ion mobility spectrometry IMS is a widely used analytical technique for field detection of chemical warfare agents CWAs, narcotics, and explosives. Detection is based on the reduced mobility K0 of the compound of interest COI. The detection windows for COIs have historically been as small as - 2 of the predicted COI K0 value K0 COI, which resulted in false-positive alarms when an interferent appeared within these wide detection windows. Accurate K0 values that are an order of magnitude better than the values given in literature lower the propagation of error when they are used to predict the drift time of an ion and reduce the width of the detection windows. An IMS instrument was constructed and interfaced with an existing time-of-flight mass spectrometer, and select K0 COI values were measured as a function of multiple instrumental parameters. This initial database of accurate K0 COI values will be expanded in the future to include additional COIs, namely CWAs toxic chemicals and explosives. The database of accurate K0 values will be used to calibrate IMS-based field instruments and reduce their rates of false-positive alarms without increasing their false-negative responses or modifying hardware.
- Chemical, Biological and Radiological Warfare
- Atomic and Molecular Physics and Spectroscopy
- Test Facilities, Equipment and Methods