An Innovative Ultramicroelectrode Array for Field-Deployable Trace Metal Analysis

60900 The need to accurately monitor the movement of radioactive and toxic metal waste in the environment has pushed the DOE to the forefront of sensor microfabrication designed for trace metal analysis. Recent advances in electroanalytical stripping analysis using novel electrode conditioning procedures has led to great improvements in sensitivity and resolution for trace metal monitoring. However, long term field deployment of these sensors is not practical because of electrode instabilities and limited sensitivities. This project will develop and field test a novel ¿submersible micro lab,¿ using a microband electrode array with individually addressable sensor elements, for long term remote monitoring and characterization of ground water sites contaminated with hazardous metal waste. In Phase I, an electrochemical microband sensor array was successfully designed and tested for the simultaneous detection of trace metal contaminants. 10-mm diameter electrodes were fabricated using lithographic and contact printing approaches. The electrodes exhibited superior adhesion and electrical properties, and the long-term stability and chemical specificity of the electrodes was demonstrated. Furthermore, ppb levels of Cr(VI) detection were achieved for groundwater samples obtained from the 100D Area of the DOE Hanford site. Phase II will optimize the fabrication methods, increase the sensitivity of electrochemical detection, and build a working unit for in situ field testing of a conducting polymer-based sensor array. Commercial Applications and Other Benefits as described by the awardee: The number of contaminated sites in the U.S. has been estimated in the hundreds of thousands. Characterization of these sites can cost between 0% and 40% of the total remediation cost, with the average being 15%. In a $ 12 billion market, this equates to $1.8 billion sales for monitoring technologies