Isotope effects of copper in Cu(II) malate ligand exchange system studied by using ion exchange displacement chromatography

The ion exchange chromatography technique was used for studying copper isotope effects in Cu-malate ligand exchange system (LXS) in the temperature range 288–353K. A highly acidic cation exchange resin (TITECH-3, 37–88 μm) was used. It had been found that the heavier isotope, 65Cu, was enriched at the front boundary, while the lighter isotope, 63Cu, was enriched at the rear boundary of the copper band at all temperatures. Such finding means that the heavier isotope, 65Cu, is preferentially fractionated into the malic complex form in the solution phase. The values of the single stage separation coefficients, ϵ=S−1, of the 63Cu/65Cu isotopic pair have been calculated and found to decrease with the increase in temperature as 2.87×10−4, 2.39×10−4, and 2.13×10−4 at 288, 333, and 353K, respectively. The height equivalent to the theoretical plate (HETP), at every temperature, was also calculated.