Separation and collection of anion complexes for subsequent radiochemical analysis

We have developed a method to separate anion complexes of radioactive sulfur, iodine, and phosphorus to enable determination by radiochemical techniques. This method involves ion-chromatographic separation of the anion complexes from other highly emitting radioactive species such as 137Cs and 90Sr which interfere with radiochemical analysis. We essentially use the ion chromatograph as a sample pretreatment method. The samples are injected onto a cation-exchange column which allows the anions to pass through while retaining the positively charged species. If more than one negatively charged radio nuclide is present, the sample is injected onto an anion-exchange column and the individual anions are separated from each other as well as from the cations. These anions are collected in the column effluent and measured by nuclear counting methods. The method was developed to enable measurement of trace radionuclides in radioactive waste and in environmental samples. Trace radionuclides that are present in concentrations of only a few hundred disintegrations-per-minute per milliliter can be separated and then analyzed using liquid scintillation counting analysis. This paper establishes the separation and collection protocol, collection efficiencies for sulfur, iodine, and phosphorus anion standards, and overall efficiencies and detection limits for the separation and subsequent radiochemical analysis of 129I from both environmental level and high-salt waste samples