Environmentally Benign Automated Nitrate Analysis

Nitrate is a serious water quality issue in many rural and agricultural areas. NECi, The Nitrate Elimination Co. Inc. proposes to demonstrate the feasibility of using purified and stabilized plant NADH:Nitrate Reductase (NaR) as a direct replacement for the cadmium columns used for nitrate determination in standard air segmented continuous flow (CF) and flow injection (FI) methods. While cadmium-based methods are accurate and reliable, the extreme toxicity of cadmium poses challenges to worker safety and environmental hygiene. NECi will partner with the Methods R&D Program Laboratory of the National Water Quality Laboratory, U.S. Geological Survey, to begin development of automated NaR-based analytical methods for nitrate in water. We will investigate reagent systems using soluble NaR and also develop immobilized NaR formulations. Formulations exhibiting reproducible and linear response to nitrate in NECi's hands will be sent to the USGS lab partner for validation on a commercial CF analyzer. Nitrate standards and natural water samples will be analyzed. The most promising formulation(s) will be further developed in Phase II. The long-term goals are 1) development of immobilized enzyme columns that can directly replace cadmium columns in standard autoanalyzer equipment: and 2) development of an economical and field-deployable nitrate analyzer.