Exploring lanthanide separations using Eichrom's Ln Resin and low-pressure liquid chromatography

Analytical methods for separating individual lanthanide elements from each other are needed to support various scientific fields. This work reports a systematic evaluation of analytical separations using Eichrom Industries Ln resin and simple peristaltic pump fed low-pressure chromatography columns. Systematic studies of isocratic elutions over a range of acid concentrations (0.10 to 0.25 M HNO3) and column lengths (15 to 45 cm) show that with careful selection of the separation conditions baseline separation of the majority of the lanthanide elements can be achieved, with the exception Nd, Pr, Pm and Ce which co-elute at low acid concentrations. The employment of a novel Ce3+/Ce4+ oxidation-reduction approach using NaBrO3 and ascorbic acid enables isolation of Ce, however baseline separation of Nd, Pr and Pm could not be accomplished using Ln resin, simple acids, and low-pressure chromatography. A method for rapid separation and preconcentration of fission product lanthanides is also reported based upon the optimized conditions identified in this work; the separation approach enables isolation of lanthanide isotopes in high purity and chemical yield, with final elution fraction volumes of 4 mLs

Automated summary

This study systematically evaluated the analytical separations of lanthanide elements using Ln resin and low-pressure chromatography columns, showing that most elements can be baseline separated with careful selection of conditions. However, Nd, Pr, Pm, and Ce co-elute at low acid concentrations. A novel Ce3+/Ce4+ oxidation-reduction approach enables the isolation of Ce, but baseline separation of Nd, Pr, and Pm remains a challenge using the current methods.