Assessment of ligand extraction properties: an intercomparison campaign amongst EUROPARTners

An intercomparison campaign was organized at the beginning of the European FP6 EUROPART Integrated Project, among the partners involved in the assessment of the extracting properties of novel ligands, in order to check their accuracy and reliability when determining metal cation distribution ratios. Three different extracting systems, presenting various selectivity and affinity towards trivalent actinides were selected: (i) CMPO, (ii) TPTZ and (iii) BTP. Although some differences could be pointed out in the implementation of liquid–liquid extraction tests, the distribution ratios measured by the nine partners were fairly reproducible (<20% deviation) for the first two extracting systems. However, large discrepancies occurred when testing the third extracting system, due to its strong hydrolytic instability, thus pointing out the difficulty of assessing extraction properties of instable ligands.