Spectroelectrochemical Sensor for Pertechnetate, TcO4-, Applicable to Hanford and Other DOE Sites
EMSL Project ID
24491a
Abstract
The general aim of our work currently funded by DOE (formerly by EMSP) is the design and implementation of a new sensor technology that offers unprecedented levels of specificity needed for analysis of the complex chemical mixtures found at DOE sites nationwide. This project involves a very successful collaboration between scientists at the University of Cincinnati (UC) and several at the Pacific Northwest National Laboratory (PNNL) and the Environmental Molecular Sciences Laboratory (EMSL). The goal of the work described in this proposal is the continued development of a sensor for 99Tc that is applicable to characterizing and monitoring the vadose zone and associated ground water. The single focus of this proposal is pertechnetate, TcO4-, which is considered to be the dominant species in the vadose zone and ground water. The sensor will have the capability for on-site monitoring, either by immersion in subsurface water for continuous monitoring or for the immediate analysis of collected samples. The project will build on the substantial progress of a well-established UC-PNNL collaboration which provides the wide range of expertise needed for success: spectroscopy, electrochemistry, device fabrication, thin film technology, synthetic inorganic chemistry, experience with Tc, and facilities for handling radioactive isotopes. The sensor will consist of an innovative fluorescence-based spectroelectrochemical configuration that we have developed under our EMSP grants: a waveguide with an optically transparent electrode that is coated with a thin chemically-selective film. It is now absolutely clear from our previous work that the fluorescence spectroelectrochemical sensor can reach limits of detection of at least 10-12 M given even a low-to-moderate quantum yield fluorescent material. We find this result very exciting since the limit of detection for an analogous Tc-based fluorescent species would need to be about 10-10 M to reach regulatory limits.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2007-06-01
End Date
2008-06-01
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members