PARENT SESSION
PM26 - Environmental Chemistry in Ecological Assessments
Monday, 18 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P456) Preliminary design, construction and operation of a sensor for the detection of nerve agent analogs.
Boyd, Jonathan*,1, Chiodo, Louis1, Murray, George1,2, Cobb, George1, 1 Texas Tech University, Lubbock, TX, U. S. A.2 The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, U. S. A.
ABSTRACT- A sensor prototype is presented for passive detection of isopropyl and pinacolyl methylphosphonate, the hydrolysis products of the nerve agents, sarin and soman. This sensor combines liquid core waveguide and molecularly imprinted polymer (MIP) technologies. The waveguide consists of Teflon ®AF 2400 filled with dilute aqueous NaOH. The MIP incorporates a functionality-imprinted copolymer containing a coordinatively bound luminescent lanthanide ion. The chemical of interest (COI), in this case sarin or soman, diffuses across the exposed teflon membrane into the liquid core, where it hydrolyzes to allow selective and reversible binding to the lanthanide complex within the MIP. The COI-MIP complex is excited by a light emitting diode in the 470-nm range and produces a narrow luminescence band in the 610-nm region of the lanthanide spectrum. The teflon waveguide propagates emitted light to a metal package photomultiplier for detection. Reversible binding of the hydrolysis product allows the sensor to be washed, ultimately resetting the sensor. Due to the inherent sensitivity and fast response time of the liquid core waveguide in conjunction with the selectivity of the MIP, this sensor has the potential to respond within seconds to a chemical release at or below the time-weighted average/airborne exposure limit (TWA/AEL), which is in the low part-per-trillion range for the nerve agents in question. We are currently evaluating the response time and detection limits of this novel sensor.
Key words: sensor, nerve agent, liquid core waveguide, molecularly imprinted polymer