In Situ Microfluidic-based Nutrient Analyzer for Long-term Deployment in Environmental Waters

Eutrophication of environmental waters from the influx of nutrients can result in ecosystem degradation caused by excessive plant and algae growth. Identification and prevention of the nutrient loading problem can be addressed with measurements from deployed instrumentation only if that instrumentation is reliable and inexpensive to use. This project will investigate the feasibility of using a deployed, micro total analysis system for the in situ measurement of nutrients in environmental waters. The system will use a microfluidic liquid handling network to yield a device that is small, light-weight, easy to deploy, and cost efficient to own and maintain. The proposed Phase I feasibility work involves the assembly of a first-generation prototype using available components and creation of a suitable interface and subsequent testing for an extended period of time to evaluate analytical figures of merit and the effects of biofouling. The Phase I study will be limited in scope and will only focus on phosphate (orthophosphate) detection using standard colorimetric methods. Our goal is to use these results to expand the scope of work in the second phase to include detection capabilities for other nutrients and to overcome or minimize any biofouling effects. Eventually we want to produce an instrument that can near-simultaneously analyze ammonium, nitrate/nitrite, phosphate, and silica. In the Phase I study the early prototype unit will be designed for deployment in a protective enclosure near a body of environmental water. In later phases, the unit will be developed for submersible deployment in both fresh and saltwater environments.