*** 96-60740 Vasudevan This Small Business Innovation Research (SBIR) Phase I Project will test a new method of detecting aromatic hydrocarbons, with particular application to monitoring subsurface concentrations of these compounds in both vapor (vadose zone) and liquid phases. Bioremediation has emerged as the method of choice to treat these contaminants. This is an opportunistic process, wherein the different aromatic compounds are degraded sequentially at varied rates. Current methods can be used to monitor the total hydrocarbon concentrations in situ, but they cannot differentiate between individual aromatic compounds. In addition, the sensitivity of current techniques (low parts per million range) is inadequate to meet current regulatory standards. Hence, new methods are required that improve sensitivity and selectivity. The Phase I sensor will provide parts per billion sensitivity for four important aromatic species, independently. Called BTEX compounds, these are benzene, toluene, ethyl benzene, and the xylenes (all isomers). The sensor will detect changes in the refractive index of a substitute cladding on a fiber-optic cable. The substitute cladding used here will be a polymer that is sensitized to bind selectively individual BTEX compounds, using a chemical method that does not change other material properties, thus imparting selectivity to an otherwise inert polymer. More than 1.5 million sites exist, in the U.S. alone, that are contaminated with petroleum hydrocarbons, to which this technology could be applied. Additional environmental sensing applications could be developed rapidly using this design methodology. ***
