Chemists at the University of Maryland, College Park, have developed a new, highly selective way to detect chemical weapons. The system uses molecules that are fluorescent in the presence of even small amounts of lethal phosphate esters.
The research is outlined in the December 2 edition of the peer reviewed Journal of the American Chemical Society, which is published by the world's largest scientific society, based in Washington, D.C.
The most common chemical weapons attack acetylcholine esterase, an enzyme in the human body which controls muscle contraction. Many current detectors employ the enzyme itself and are very sensitive. However, they also detect benign chemicals that inhibit acetylcholine esterase, including many pesticides.
To better target just dangerous substances, the new method uses molecules made to react specifically with volatile fluoro- and cyano- phosphate esters. They are the active ingredients in nerve agents like SARIN, which was used by terrorists in a 1995 Japanese subway attack. "Our molecules will selectively detect the phosphate esters that would injure you or me. Our molecules are more specific," claims University of Maryland chemist Robert S. Pilato, Ph.D.
For safety, Pilato's laboratory is testing the molecules against chemical weapon mimics. These phosphate esters react identically to warfare agents, but have vapor pressures too low to amass a lethal dose. The scientists engineered their molecules so that reaction with those gases produced another molecule that fluoresces.
In order to detect the fluorescence, the sensor molecule is immobilized in a polymer matrix which could be used to coat fiber optics. Says Pilato: "The next step is to take those polymer immobilized molecules and screen them against the real McCoy."
A nonprofit organization with a membership of more than 155,000 chemists and chemical engineers, the American Chemical Society publishes scientific journals and databases, convenes major research conferences, and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.
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