Mass-dependent and mass-independent isotope effects of zinc in chemical exchange reactions using liquid chromatography with a cryptand stationary phase

Abstract

Zinc isotopes were fractionated using liquid chromatography with a cryptand(2_B,2,2) polymer stationary phase. The breakthrough operation was performed at 293 or 313 K with a feed solution of concentrated ZnCl₂ in HCl. In the front end of the elution curve, a mass-dependent isotope effect was predominantly observed. A mass-independent isotope effect appeared with increase of the concentration of zinc in the effluent. The mass-independent isotope effect was well explained by using nuclear size and shape and nuclear spin effects. In the middle of the elution curve, the nuclear mass effect and the field shift effect were calculated separately. The field shift effect was 1.1–1.3 times as large as the nuclear mass effect in absolute value and showed the opposite sign.