Zinc isotope effects by chromatographic chelating exchange resin

Isotope effects of neodymium in different ligands exchange systems studied by ion exchange displacement chromatography

The isotope effects of neodymium in Nd-glycolate ligand exchange system were studied by using ion exchange chromatography. The separation coefficients of neodymium isotopes, ε's, were calculated from the observed isotopic ratios at the front and rear boundaries of the neodymium adsorption band. The values of separation coefficients of neodymium isotopes, ε's, for the Nd-glycolate ligand exchange system were compared with those of Nd-malate and Nd-citrate, which indicated that the isotope effects of neodymium as studied by the three ligands takes the following direction Malate > Citrate > Glycolate. This order agrees with the number of available sites for complexation of each ligand. The values of the plate height, HETP of Nd in Nd-ligand exchange systems were also calculated.

Chromatographic Zinc Isotope Separation by Chelating Exchange Resin

Zinc isotope separations were studied by displacement chromatography using the chelating properties of malate, citrate and lactate exchange resin and EDTA as ligands. After each chromatographic operation, the heavier zinc isotopes were found to preferentially fractionated into the carboxylate complex solution phase. The separation coefficients (ε) for zinc isotope separation had the largest value and were obtained for the isotopic pairs ⁶⁸Zn/⁶⁴Zn (7.16 × 10⁻⁴) and ⁶⁶Zn/⁶⁴Zn (3.08 × 10⁻⁴), respectively, at 298 ± 1 K. The separation coefficient per unit mass differences (ε/ΔM) for the isotopic pair of ⁶⁸Zn/⁶⁴Zn was found to range around 1.55 × 10⁻⁴.