Sequential separation of actinides by ion chromatography coupled with on-line scintillation detection

The separation and measurement of actinides by ion chromatography (IC) coupled with on-line scintillation detection was investigated. Separation of 237Np, 239Pu, 241Am, 244Cm, 230Th, and 233U was accomplished using a Dionex CG5 guard column, CS5 separation column, and an elution program utilizing oxalic, diglycolic, and nitric acid eluents. Np(V) was eluted as a weak anionic oxalate complex or as free NpO2+ cation, Am(III) and Cm(III) as anionic oxalate complexes, Pu(IV) and Th(IV) as non-ionic diglycolate complexes, and U(VI) as a free uranyl cation. Response of the flow-cell detector was linear over the full range of activities tested (4-1500 Bq). The minimum detectable activities for the investigated analytes ranged from 3.6 Bq for 244Cm to 5.4 Bq for 230Th and 239Pu. The corresponding minimum detectable concentrations based on a 1-L sample ranged from 3.6 to 5.4 KBq m-3 (96 to 150 pCi L-1).