Efficient screening of cation exchange resins for radiolanthanide separations

This study presents a rapid analysis method for characterizing ion exchange resins used in radiolanthanide separations. Fourier Transform Infrared Spectroscopy (FTIR) analysis, combined with manufacturer-reported bead size, allows for the prediction of resin separation efficiency. Via FTIR, four subclasses ( type A-D) of commercially available strong cation exchange resins with a polystyrene-divinylbenzene (PS-DVB) polymer base were identified, with variations in the 1000–1300 cm −1 region indicating the presence or absence of sulfonate functional groups and sulfone bridges. Type A resins with functional sulfonate groups showed superior separation resolution in the three-lanthanide system (dysprosium, terbium and gadolinium) as compared to other subclasses. Type B resins showed evidence of sulfone bridges , which reduce the availability of sulfonate functional groups and resulted in reduced lanthanide separation resolution . Type C and D resins showed minimal sulfonate functional groups and this corresponded to reduced analyte retention. Additionally, the DVB density of ion exchange resins was found to correlate with the process time of their chromatographic separation, although separation resolution appeared unaffected by cross-linking. This novel method of resin evaluation combining bead size and FTIR enables a reduction in the time, cost and waste generated relative to chromatographic evaluation. Thus, this approach offers a significant improvement in practical efficiency for evaluating the utility of PS-DVB resins in chromatographic separations. • FTIR can be used as a screening method for selecting cation exchange resins for radiolanthanide separations. • FTIR decreases evaluation time, materials used, and waste generated relative to chromatography. • Different crosslinking methods affect the accessibility of sulfonate groups in cation exchange resins impacting separation performance.