GAS-CHROMATOGRAPHIC SEPARATION OF PAIRS OF ISOTOPIC MOLECULES

Nine pairs of isotopic (hydrogen/deuterium) molecules have been comple tely separated and quantitatively determined by gas chromatograph usin g a DB-5 column. All pairs exhibited an inverse isotope effect. The di fferences of enthalpy, entropy and free energy changes have been calcu lated for the chromatographic process. The data show that deuterium on the aliphatic part of a molecule makes more of a contribution to the inverse isotope effect than those on aromatic rings.