9613556 Thompson This proposal seeks to develop fluorescence-based sensors for chemical analytes of environmental interest, including mercury, cadmium, nickel cyanide, nitrate, sulfide, and others. The sensors incorporate optical fibers for remote sensing in process and wastewater monitoring applications. They can also be designed to be handheld and used in field work. In both cases the sensors offer significant advantages over current technology, which mostly involves sampling followed by subsequent analysis in a distant laboratory. These sensors are fluorescence-based, and employ a biomolecule as the transducer element in which the biomolecule exhibits a change in its fluorescence lifetime or anisotropy upon recognition of the target chemical. To optimize the sensing properties, site-directed mutagenesis will be used to develop new variants of the biomolecule. For the fiber optic sensors, the biomolecules will be incorporated into existing sensor apparatus for testing. For the anisotropy-based sensors, the applicants will construct a new solid state mini-fluorometer. The mini- fluorometer is intended for field use. Additional advances in components may enable it to achieve one hundred-fold better precision, and thereby improve accuracy and detection limits. The significance of the proposed effort is three-fold. These new sensors are intended to make monitoring of process water recycling, wastewater outflows, and ground water simpler, safer, more precise, less costly, and more automated. Improved sensors may not only make processes more efficient and fail-safe, but, in the case of nitrates, they may reduce the cost to the farmer and reduce pollution by preventing over-fertilizing. These new sensors also may be precise enough to provide results comparable with current Environmental Protection Agency (EPA) standard methods.
