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

Abstract

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 99 Tc , a pure β −-emitter, in spinach plants. The actual leaf concentration of two technetium species, i.e. 99 TcO − 4 and 99 TcX (plant-formed Tc species), is determined as a function of incubation time with 99 TcO − 4 in the substrate. Addition of 95 m TcO − 4 or 99 m TcO − 4 , both containing a γ-emitting radioisotope of technetium, to the substrate allows easy radiotracing, while addition of 99 m TcO − 4 or 95 m TcX 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.