Spectroelectrochemical Sensor for Technetium: Preconcentration and Quantification of Pertechnetate in Polymer-Modified Electrodes

In Situ Quantification of [Re(CO)3]+ by Fluorescence Spectroscopy in Simulated Hanford Tank Waste

“…The pretreatment protocol is designed to accomplish several things simultaneously: (1) The developer solution contains a diamine sensitizing ligand in high enough concentration that allows for binding to the target [Re(CO) 3 ] + species. (2) The sensitizing ligand can be chosen based on its affinity for the target [Re(CO) 3 ] + species over other competing ligands in a waste sample.…”

“…Consequently, it has been declared a major EPA Superfund site that is undergoing cleanup. One aspect of the remediation efforts includes the separation of low- and high-level activity waste . The need to characterize and monitor various constituents of interest in these underground storage tanks presents a major scientific challenge, particularly concerning moving high-activity constituents, such as water-soluble radionuclides, prior to immobilization.…”

“…Optical spectroscopy is a quick nondestructive method that would be useful for detection of the [Tc I (CO) 3 ] + species. Previously, the quantitative measurement of various Tc species using both absorption and fluorescence spectroscopy, as well as the luminescence-based spectroelectrochemical detection of Tc­(II) species, both in solution and in film, have been demonstrated. One challenge with detecting the [Tc I (CO) 3 (L) 3 ] n − species is that it does not have a unique signature using routine optical spectroscopic techniques and is indistinguishable from other constituents stored in the waste tanks.…”

Further Investigations on a Poly(Vinyl Alcohol)— Polyelectrolyte Chemically Selective Optical Film

“…In the course of designing spectroelectrochemical sensors for radioactive waste materials, we have discovered that one polymeric film material, namely, that consisting of poly(vinyl alcohol) entrapped poly(vinylbenzyltrimethylammonium chloride), designated herein as PVTAC-PVA, shows very promising characteristics with respect to preconcentrating pertechnetate ( 99 TcO 4 Ϫ ), which is a substance of concern at nuclear waste sites nationwide. 13 It therefore became important to more carefully study the detailed physical and optical properties of this new film material for possible use in sensors at such sites. Because of the current direction of our work, it also became necessary to investigate both the chemical reversibility and the compatibility with fluorescence detection of the film.…”

Optically Transparent Thin-Film Electrode Chip for Spectroelectrochemical Sensing

“…Our group has demonstrated the use of optically transparent electrodes (OTEs) consisting of ITO deposited on a glass substrate for a variety of applications, including the spectroelectrochemical sensing of polycyclic aromatic hydrocarbons by fluorescence, , rhenium and technetium detection by absorption and fluorescence, ,, ruthenium in natural and drinking water, and ferrocyanide detection in the presence of interfering species in Hanford tank nuclear waste samples. − ITO has also recently been shown to be useful for nonspectroscopic techniques, such as cathodic stripping voltammetry to detect manganese where the positive potential limit and low background current are advantageous . An electrode chip consisting of an ITO working electrode, as well as planar auxiliary and reference electrodes, would combine the powerful techniques of spectroscopy and electrochemistry into a highly selective and versatile sensing platform for the detection of a number of hard-to-detect species.…”