NEW FLUORESCENT COMPOUNDS DEVELOPED BY A RESEARCH GROUP AT MASSACHUSETTS INSTITUTE OF TECHNOLOGY may soon be used to sniff out some of the estimated 120 million unexploded land mines hidden around the world. The polymers, which glow yellow, are described in the Nov. 25 issue of the Journal of the American Chemical Society. They are sensitive enough to detect extremely dilute trace vapors of TNT, which waft into the air directly above a buried land mine.
When these highly sophisticated chemical sensors bind to TNT, the polymers' fluorescent intensity decreases significantly. The binding of just one molecule of TNT is enough to cause a measurable dimming of the polymers. That means they can be used to detect TNT in concentrations as dilute as 10 to 100 parts per billion.
Timothy M. Swager, the lead author of the study, believes these novel polymers could be used in low-cost, handheld mine detectors. He is working with a Stillwater (Okla.)-based company called Nomadics Inc. to develop a prototype. In the future, the polymers, and the portable detection devices that will contain them, could also find a home at airport security checkpoints, alerting inspectors to hazardous chemicals, firearms, and drugs such as cocaine and heroin, all of which give off trace vapors.