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

A pretreatment protocol is presented that allows for the quantitative conversion and subsequent in situ spectroscopic analysis of [Re(CO)3]+ species in simulated Hanford tank waste. In this test case, the nonradioactive metal rhenium is substituted for technetium (Tc-99), a weak beta emitter, to demonstrate proof of concept for a method to measure a nonpertechnetate form of technetium in Hanford tank waste. The protocol encompasses adding a simulated waste sample containing the nonemissive [Re(CO)3]+ species to a developer solution that enables the rapid, quantitative conversion of the nonemissive species to a luminescent species which can then be detected spectroscopically. The [Re(CO)3]+ species concentration in an alkaline, simulated Hanford tank waste supernatant can be quantified by the standard addition method. In a test case, the [Re(CO)3]+ species was measured to be at a concentration of 38.9 μM, which was a difference of 2.01% from the actual concentration of 39.7 μM.