Kalousek, P
1991
Hand-Portable Gas Chromatography/Ion Mobility Spectrometry: The "Poor Man's" CB System?
Meuzelaar, H.L.C.; Kim, M.-G.; Arnold, N.S.; Kalousek, P. and Snyder, A.P.
US Army Research Office Workshop on Spectrometry and Spectroscopy for Biologicals, Cashiers, NC, 1991. Funded by US Army/Chemical Research Development and Engineering Center and US Department of Defense/Army Research Office.
The capabilities of ion mobility spectrometry (IMS) with regard to the detection and identification of chemical warfare agents are widely recognized. Tens of thousands of IMS based CAM® (Chemical Agent Monitor) systems manufactured by Graseby Ionics (Watford, U.K.) are currently in use by NATO forces, including US Army Marine Corps.
The hand-held, battery powered CAM draws approx. 500 ml. min-1 of ambient air over a heated silicone rubber membrane covering the entrance to the ionization chamber (a Ni-63 source) and the IMS drift tube region both of which are being operated slightly below ambient pressure. A Faraday cup detector registers the arrival time of mobile ion species traversing the drift tube at different velocities after being admitted into the drift tube region by gating pulses at 20 msec intervals. Typical drift times ("mobilities") of ion species representing volatile organic compounds are in the 5-10 msec range. The CAM can be operated in either positive or negative ion detection mode (switch selectable).
In spite of the successful development and application of the CAM for detecting chemical warfare agents, several remaining shortcomings inherent to IMS based detection devices (e.g., limited ability to distinguish between individual components in complex mixtures as well as low dynamic range and lack of linear response), seriously hamper its application as a quantitative detection tool. Moreover, only organic species that readily pass through the silicone rubber membrane can be detected. This prevents the use of the CAM for detection of nonvolatile materials such as most biological warfare agents.
1990
Man-Portable Gas Chromatography/Ion Mobility Spectrometry System: GC/CAM
Meuzelaar, H.L.C.; Kim, M.-G.; Arnold, N.S.; Urban, D.T. ; Kalousek, P.; Snyder, A.P. and Eiceman, G.A.
US Army Chemical Research Development and Engineering Center Scientific Conference on Chemical Defense Research, Aberdeen Proving Grounds, Maryland, 1990. Funded by US Army Chemical Research Development and Engineering Center.
Currently there is widespread interest in extending the capabilities of ion mobility spectrometry (IMS) to various military as well as nonmilitary fields of application, including chemical demilitarization, treaty verification, drug enforcement, explosives detection and environmental monitoring. Characteristic features of IMS are high sensitivity, fast response, low weight, small size, low power requirements, and relatively low cost. An attractive approach is to add a front-end module capable of performing "transfer line gas chromatography" (TLGC). In its present form the TLGC/IMS system consists of a special automated air sampling valve, a short (1-2 m long) capillary GC column with isothermal oven, a Chemical Agent Monitor (CAM) and a small laptop PC. The IMS system is operated below ambient pressures.
Kalousek, P
1991
Hand-Portable Gas Chromatography/Ion Mobility Spectrometry: The "Poor Man's" CB System?
Meuzelaar, H.L.C.; Kim, M.-G.; Arnold, N.S.; Kalousek, P. and Snyder, A.P.
US Army Research Office Workshop on Spectrometry and Spectroscopy for Biologicals, Cashiers, NC, 1991. Funded by US Army/Chemical Research Development and Engineering Center and US Department of Defense/Army Research Office.
The capabilities of ion mobility spectrometry (IMS) with regard to the detection and identification of chemical warfare agents are widely recognized. Tens of thousands of IMS based CAM® (Chemical Agent Monitor) systems manufactured by Graseby Ionics (Watford, U.K.) are currently in use by NATO forces, including US Army Marine Corps.
The hand-held, battery powered CAM draws approx. 500 ml. min-1 of ambient air over a heated silicone rubber membrane covering the entrance to the ionization chamber (a Ni-63 source) and the IMS drift tube region both of which are being operated slightly below ambient pressure. A Faraday cup detector registers the arrival time of mobile ion species traversing the drift tube at different velocities after being admitted into the drift tube region by gating pulses at 20 msec intervals. Typical drift times ("mobilities") of ion species representing volatile organic compounds are in the 5-10 msec range. The CAM can be operated in either positive or negative ion detection mode (switch selectable).
In spite of the successful development and application of the CAM for detecting chemical warfare agents, several remaining shortcomings inherent to IMS based detection devices (e.g., limited ability to distinguish between individual components in complex mixtures as well as low dynamic range and lack of linear response), seriously hamper its application as a quantitative detection tool. Moreover, only organic species that readily pass through the silicone rubber membrane can be detected. This prevents the use of the CAM for detection of nonvolatile materials such as most biological warfare agents.
1990
Man-Portable Gas Chromatography/Ion Mobility Spectrometry System: GC/CAM
Meuzelaar, H.L.C.; Kim, M.-G.; Arnold, N.S.; Urban, D.T. ; Kalousek, P.; Snyder, A.P. and Eiceman, G.A.
US Army Chemical Research Development and Engineering Center Scientific Conference on Chemical Defense Research, Aberdeen Proving Grounds, Maryland, 1990. Funded by US Army Chemical Research Development and Engineering Center.
Currently there is widespread interest in extending the capabilities of ion mobility spectrometry (IMS) to various military as well as nonmilitary fields of application, including chemical demilitarization, treaty verification, drug enforcement, explosives detection and environmental monitoring. Characteristic features of IMS are high sensitivity, fast response, low weight, small size, low power requirements, and relatively low cost. An attractive approach is to add a front-end module capable of performing "transfer line gas chromatography" (TLGC). In its present form the TLGC/IMS system consists of a special automated air sampling valve, a short (1-2 m long) capillary GC column with isothermal oven, a Chemical Agent Monitor (CAM) and a small laptop PC. The IMS system is operated below ambient pressures.