Grantee Research Project Results

Final Report: The Application of MASC Technology to the Problem of Contaminant Monitoring for the Water and Wastewater Industries

EPA Contract Number: 68D02009
Title: The Application of MASC Technology to the Problem of Contaminant Monitoring for the Water and Wastewater Industries
Investigators: Orser, Cindy S.
Small Business: Arete Associates
EPA Contact: Richards, April
Phase: I
Project Period: April 1, 2002 through September 1, 2002
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2002) RFA Text |  Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , SBIR - Monitoring , Small Business Innovation Research (SBIR)

Description:

The principles of Modeling of Active Site Chemistry (MASC) are based on a technological adaptation of natural organisms and their biological properties. Through evolution, many organisms have developed highly sensitive and selective mechanisms for sensing and responding to their local environment. These highly adaptive processes often are enzyme mediated, and thus extraordinarily sensitive to a very narrow range of targets. Adapting these sensory enzymes into electronic monitoring devices, at least conceptually, represents an ideal technology for environmental monitoring. The primary obstruction in utilizing these enzymes as a detector is their inherent lability once they are removed from their cellular environment.

The focus of this research project is to use chemical systems to emulate the function of these active sites without their inherent fragility. There are several advantages to this technology. First, using chemical compounds extends both the active life and shelf life of these detectors. Second, chemical synthesis is much more amenable to manufacturing and mass production. The cost for producing these sensors would make them more cost-effective than the devices currently employed in the water and wastewater industries. This proof-of-concept project utilized the enzyme nitrate reductase as the enzyme to be mimicked.

Summary/Accomplishments (Outputs/Outcomes):

Areté Associates found the sensor to be both selective and sensitive for the target analyte, nitrate. The miniaturization of the sensor was successful. The optimal conditions for the sensor were discovered and utilized to achieve a range of detection from 2 ppm to 500 ppm nitrate-nitrogen. Consistent calibration curves were achieved, and deviation from the known values of check standards was minimal. Repeat analysis of standards and samples demonstrated exceptional reproducibility. The sensor also was easily maintained in peak working conditions, and could make more than 30 readings before a 20-second reconditioning was needed, which restored the sensor to its original condition. Using the sensor in an in-line capacity also proved successful, demonstrating very quick reaction to nitrate concentration in a continuous monitoring application.

Conclusions:

The results from this Phase I research project of the MASC sensor demonstrate that the sensor is sensitive (< 2 ppm N-NO3), accurate to 96.7 percent, selective, and highly reproducible (Coefficient of Variation = 1.12%), and thus merits continued research and development support and funding of the concept. The sensor demonstrates remarkable selectivity in the first round of examinations. Thirteen different commonly encountered contaminates (such as nitrites, sulfates, sulfites, potassium, and sodium) were tested, and none of them were found to interfere with the detection of nitrate. One point that would bear further investigation and streamlining is the manufacture of the sensor element itself. Although the concept has been proven to be correct, there is a small level of inter-sensor variation. Refinements of the manufacturing process should eliminate this effect. A final area for further development is continuous flow monitoring for nitrate-nitrogen. Initial experiments and results demonstrated the feasibility of this effort, but more work is needed on standardization and collection.

Supplemental Keywords:

nitrate analysis, continuous flow monitoring, wastewater industry, modeling of active site chemistry, MASC, contaminants, nitrogen, SBIR., RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Water, Toxics, POLLUTANTS/TOXICS, National Recommended Water Quality, Chemical Engineering, Mercury, Environmental Chemistry, Engineering, Chemistry, & Physics, Wastewater, Monitoring/Modeling, Arsenic, Drinking Water, Environmental Engineering, Environmental Monitoring, Water Pollutants, community water system, biosensors, field detection, Chromium, field portable monitoring, industrial wastewater, measurement, MTBE, field portable systems, chemical contaminants, environmental measurement, monitoring, chemical detection techniques, analytical methods, drinking water system, drinking water contaminants, drinking water regulations, environmental contaminants, field monitoring, MASC technology, cyanide, analytical chemistry, risk management, arsenic exposure, detection