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A new type of radio frequency identification (RFID) sensor for gaseous molecules has been created based on a standard RFID tag coated with a chemically sensitive film at low cost. The use of multivariate analysis allows these new RFID sensors to be used to identify and quantify vapours important to industrial, in health, law enforcement, and of security applications. Radislav Potyrailo and William Morris of the Materials Analysis and Chemical Sciences Technology at General Electric Global Research Center, in Niskayuna, New York, explain the benefits of their new technology in a forthcoming issue of the journal Analytical Chemistry. "Distributed sensor networks are critical for numerous applications such as monitoring of transport of pollution plumes across the perimeters of industrial plants, leak detection from storage tanks, health monitoring of buildings, large-area tracking of contamination sources in natural water supplies, and spatially resolved combinatorial screening of materials," they explain. Fibre-optic distributed and multiplexed point sensors as well as so-called "smart dust" sensors, and wireless sensor networks have all found their place in such applications. However, all such approaches have inherent problems and costs. The GE team has turned to RFID as an emerging technology that might provide a novel, low cost alternative. The cost of RFID tags has plummeted recently, as often happens with new electronics technology. Potyrailo and Morris realised that simply coating an RFID tag with a chemically sensitive polymer layer would allow them to build an inexpensive distributed sensor network. Multianalyte chemical identification and quantitation of the data from the network of coated RFID tags would allow them to measure four parameters at once from a single RFID sensor. They have now demonstrated proof of principle on several important vapours of interest to industry and various agencies: ethanol, methanol, acetonitrile, and water. "With a careful selection of the sensing film and measurement conditions," the researchers say, "we achieved parts-per-billion vapor detection limits in air." Related links:
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