The Development and Application of High Performance Liquid Chromatography Capabilities for Lanthanide Separations

Nuclear fission produces multiple lanthanide (Ln) isotopes, many of which yield valuable insights into the type and origin of nuclear material. The ability to carefully separate and analyze selected lanthanide radioisotopes can therefore be a key tool for nuclear forensic applications. An effective method for separation of lanthanide cations is High Performance Liquid Chromatography (HPLC). HPLC techniques have long been used to separate lanthanides, and our goal has been to modernize current capabilities through the development of both a new ‘non-rad’ test system and an expansion of the current rad capabilities. The chemistry is well developed, selective stripping of trivalent lanthanide cations from a cation exchange resin using α-hydroxyisobutyric acid (HIBA), but instrumentation advances yield scope for process improvements. Recently, a new HPLC system has been installed comprising of quaternary pumps, column and a Diode Array detector that allows for post column on-line analysis. Addition of PAR (4(-Pyridylazo)resorcinol)) for post column derivatization facilitates accurate determination of lanthanide cation elution using the diode array detector. This new system then served as a template for the installation of a new multi-column radiological HPLC. The application of both capabilities towards the development of enhanced Ln separations will be described.