A dual radiotracer speciation technique with emphasis on probing of artefacts: a case study for technetium and spinach (Spinacia oleracea L.) Original Research Article

Speciation is required for obtaining information on chemical reactivity, toxicity and bioavailability of an element. In this work, a novel analytical speciation methodology, using a dual radiotracer technique is described. The approach is illustrated with the speciation of 99Tc, a pure β−-emitter, in spinach plants. The actual leaf concentration of two technetium species, i.e. 99TcO−4 and 99TcX (plant-formed Tc species), is determined as a function of incubation time with 99TcO−4 in the substrate. Addition of 95mTcO−4 or 99mTcO−4, both containing a γ-emitting radioisotope of technetium, to the substrate allows easy radiotracing, while addition of 99mTcO−4 or 95mTcX yield tracers during the analytical homogenisation procedure makes it possible to correct for procedural losses and redox conversions. For TcO−4 significant procedural losses were observed, while for TcX procedural recovery was nearly quantitative. Significant procedural conversions of TcO−4 or TcX were not observed. Speciation of other elements might benefit from this novel methodology.