Web cameras see chemistry anywhere

With an eye on making environmental, medical, food quality, and other chemical-based analyses cheap and easy wherever a computer can run, scientists in Italy and Sweden have co-opted standard liquid-crystal display monitors and webcams to serve as optical systems for detecting chemicals (Angew. Chem. Int. Ed. 2006, 45, 3800). With Internet connections, the technique could lead to distributed sensing applications such as "mapping outbreaks of flu and environmental disturbances in a way that is impossible today," suggests Ingemar Lundström of Linköping University, in Sweden. As a proof of principle, he and his colleagues exposed semitransparent films of gas-sensitive porphyrin-based compounds to low concentrations of pollutants including carbon monoxide and nitric oxides. Using a programmed sequence of 50 colors on an LCD monitor, the researchers illuminated the gas-bearing films while detecting the transmitted light with a Web camera. With software of their own design running on the same computer driving the monitor and webcam, the researchers showed that they could extract optical fingerprints for each pollutant. In time, the researchers say, the world's computer network could become a tool for chemical surveillance on any scale.