Scientists at the University of California at San Diego have developed a tiny, inexpensive sensor chip able to detect trace amounts of hydrogen peroxide, a chemical used in the most common form of homemade explosives. The scientists believe the sensor could have widespread applications in improving industrial workers’ health, by providing an inexpensive tool to monitor toxic hydrogen peroxide vapors from bleached pulp and other products to which factory workers are exposed.
The sensor monitors the variability of electrical conductivity through thin films of metal phthalocyanines. When exposed to hydrogen peroxide, an oxidant, the metal phthalocyanine films behave differently depending on the metal used. Films made of cobalt phthalocyanine show decreases in current, while those made from copper or nickel show increases in current. The scientists used this trait to build their sensor, which incorporates thin films of both cobalt phthalocyanine and copper phthalocyanine, to display a unique signature when traces of hydrogen peroxide are present.
“The detection capability of this tiny electronic sensor is comparable to current instruments, which are large, bulky and cost thousands of dollars each,†said William Trogler, a professor of chemistry and biochemistry at UCSD and one of its inventors. “If this device was mass produced, it’s not inconceivable that it could be made for less than a dollar.†Scientists hope the sensors can prevent tragedies such as the London transit bombings in July 2005, when bombs constructed of hydrogen peroxide killed more than 50 people and injured 700 more on two London subway trains and a bus during rush hour.
