Spectroelectrochemical Sensor for Pertechnetate Applicable to Hanford and Other DOE Sites

Heineman, William R. ; Seliskar, Carl J. ; Bryan, Samuel A. ; Hubler, Timothy L.

关键词: CATIONS;    DETECTION;    FLUORESCENCE;    HEAVY METALS;    MODULATION;    PERTECHNETATES;    SENSITIVITY;    TANKS pertechnetate;    technetium;    chemical sensor;    spectroelectrochemical sensor;    Hanford site;   

DOI  :  10.2172/967361
RP-ID  :  DOE/ER/63655-Final
PID  :  OSTI ID: 967361
Others  :  TRN: US201010%%425

学科分类：环境科学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

During the period of this grant several significant milestones have been passed pursuant to designing a fluorescence sensor for pertechnetate (TcO4-). They are as follows: Fluorescence spectroelectrochemistry and less than picomolar limit of detection for a model non-radioactive analyte have been demonstrated. The spectroelectrochemical sensor and associated instrumentation for fluorescence mode of operation have been made, are portable, and easily transported to and used at DOE sites. The sensor has sufficient selectivity for its application to complex samples, even including tank waste, that exist at DOE sites such as the Hanford Site. Pertechnetate has been preconcentrated in sensor films and electrochemically reduced. This is the first critical step in operation of a spectroelectrochemical sensor for TcO4-. New Tc complexes have been made that fluoresce and these complexes have been preconcentrated and electrochemically modulated in a sensor film leading to fluorescence modulation, which is the second critical step in operation of the spectroelectrochemical sensor for TcO4-. We have determined that fluorescence offers a means of dramatically improving the limit of detection. Based on measurements on our new fluorescent complexes of Tc, we estimate the limit of detection for the sensor to be 5 x 10-12M. In related work, we have shown that the sensitivity of the spectroelectrochemical sensor for some metal cations can be improved by forming a metal complex with better optical and electrochemical properties. In addition, some heavy metals can be detected with the spectroelectrochemical sensor by depositing them directly as metals on the sensor surface.