Using a silicon chip and parts from an inexpensive CD player, chemists at the University of California, San Diego have developed a portable nerve-gas sensor capable of detecting "G-type" nerve agents, such as sarin, soman and GF.
The achievement should eventually permit the development of a large number of small and inexpensive sensors that could be deployed by soldiers across a battlefield or by police after a terrorist explosion to rapidly detect the presence of certain nerve agents and to track the movements of the deadly plumes.
"With multiple sensors that have a radio transmitter attached to them, you can tell how big the cloud is and where it is moving and relay that information to a base station," says Michael J. Sailor, a professor of chemistry and biochemistry at UCSD. He will provide details of his group's achievements today at the 220th national meeting of the American Chemical Society in Washington, DC.
The innovative silicon sensor was constructed by a team that included William C. Trogler, a professor of chemistry and biochemistry, and postdoctoral associates Sonia Letant and Honglae Sohn. It works by selectively detecting compounds with a phosphorus-fluorine chemical bond, such as sarin, at very low concentrations.
To accomplish this, the scientists used a catalyst that Trogler and his co-workers had developed for the Army to detoxify materials containing nerve agents and other deadly chemicals with phosphorus-fluorine bonds. This catalyst breaks the phosphorus-fluorine bond in "G"-type nerve agents, resulting in the production of hydrogen fluoride, which is used commercially to etch and frost glass.
The sensor detects the presence of hydrogen fluoride through a silicon interferometer-a stamp-sized silicon wafer, similar to a computer chip, with an optical coating containing the catalyst. The rainbow-colored optical coating, which is akin to the sheen left by a thin film of oil on water, changes color when mole
Contact: Kim McDonald
University of California - San Diego