Method Validation and Approval: An Outsider's Perspective

Oral Presentation

Prepared by E. Campbell
NECi, 334 Hecla Street, at 217 Calumet St, Lake Linden, MI, 49945, United States


Contact Information: ellenr@nitrate.com; 906.296.1000


ABSTRACT

NECi was founded in 1993 based on a paper published in Nature on an immobilized enzyme system for taking nitrate out of water and converting it to nitrogen gas. As academics, our work had previously shown that one of the enzymes in this system, nitrate reductase, could be used to detect nitrate in complex matrices – in this first case, plant tissue extracts. NECi’s first customer for nitrate reductase was Sigma Chemical Company, followed by biomedical research product companies who purchase enzyme to incorporate into their own kits for measuring picomoles of nitrate in biological fluids. Results have to be accurate – researchers are developing medicines and therapies based on this data. Initial funding for assay development came from the USDA’s SBIR program, for onsite tests kits to determine nitrate in soil and hay. Accuracy here determines crop yield, or protects livestock from nitrate toxicity.
Moving to nitrate in water was the next logical step. Nitrate reductase (NaR) reduces nitrate to nitrite. The reaction is fast and irreversible, at gentle temperatures in aqueous solutions. Enzymes are keyed to their substrates and react with them at low concentration in complex mixtures. NaR seemed like the ideal replacement for cadmium-based reduction. Detection of the nitrite produced reacts with the same Griess reagents; the change in the method is straightforward. NECi is grateful to Charles Patton at the USGS, and some of the manufacturers of discrete analyzers, for championing this alternative method.
The barriers to adoption of superior new methods are surprising when regarded from this viewpoint. There is no argument with the regulated community’s need for reliable and reproducible data quality. In today’s world, there IS need for methods that generate less waste, and are gentler and safer for lab personnel. How do we create better pathways to quicker method validation and acceptance? Who blinks first?