Characterization of SuperLig® 620 solid phase extraction resin was performed in order to develop an automated on-line process monitor for 90Sr. The main focus was on strontium separation from barium, with the goal of developing an automated separation process for
90Sr in high-level wastes. High-level waste contains significant 137Cs activity, of which 137mBa is of great concern as an interference to the quantification of strontium. In addition barium, yttrium and plutonium were
studied as potential interferences to strontium uptake and detection. A number of complexants were studied in a series of
batch Kd experiments, as SuperLig® 620 was not previously known to elute strontium in typical mineral acids. The optimal separation was found using a 2 M nitric
acid load solution with a strontium elution step of ~0.49 M ammonium citrate and a barium elution step of ~1.8 M ammonium
citrate. 90Sr quantification of Hanford high-level tank waste was performed on a sequential injection analysis microfluidics system coupled
to a flow-cell detector. The results of the on-line procedure are compared to standard radiochemical techniques in this paper.