Radiochemical sensor system for the analysis of 99Tc(VII) in groundwater

Direct determination of 99Tc in groundwater using a sensor device represents a substantial challenge due to the short range of beta-particles, the presence of radiological interferences, and low-level detection requirements. This paper describes a radiochemical sensing method for selective detection of 99Tc(VII) in water. The sensing approach uses a dual- function compositesensor microcolumn that incorporates both selective sorption and scintillating properties. Analyte detection is carried out in a reagentless equilibration sensing regime using chemically unmodified groundwater. The sensor method was implemented in a prototypical probe device that integrates the sensor element, scintillation detection, data acquisition, and instrument controlcomponents in a single functional instrument compatible with a 3.5" well casing geometry. The feasibility of rapid 99Tc analysis in Hanford groundwater ( Hanford Site, USA) below regulatory drinking water level of 33 Bq/l was demonstrated.