Syntheses and separating properties of triazacrown and AM18C6 bonded Merrifield peptide resins

Separation of lithium and magnesium isotopes by cation exchange elution chromatography was carried out with a synthesized 1,13,16-trioxa-4,7,10-triazacyclooctadecane (N3O3)-4,7,10-trimerrifield peptide resin and with a 2′-aminomethyl-18-crown-6 (AM18C6) bonded Merrifield peptide resin. The resins have a capacity of 0.1 and 2.3 meq/g dry resin. A single stage separation factor of lithium isotopes, 1.018 was obtained by the Glueckauf theory from the elution curve and isotopic assays. The heavier isotope, 7Li was concentrated in the resin phase, while the lighter isotope, 6Li concentrated in the solution phase. On the other hand, the heavier isotopes of magnesium were concentrated in the solution phase, while the lighter isotopes were concentrated in the resin phase. The separation factors of 24Mg–25Mg, 24Mg–26Mg, and 25Mg–26Mg isotope pair fractionations were 1.012, 1.022, and 1.012, respectively.