concentrations in the environment and thus provide information
on the fates of hydrocarbons in that context (Pond et al.,
2002).
Isotope fractionation during evaporation is driven by the
molecular forces between molecules rather than the breaking
of chemical bonds within a molecule, and this phenomenon
has been explained in terms of binding energies (Grootes et
al., 1969) and molecular structure (Bradley, 1954). Most
studies to date have focused on isotope fractionation in the
context of natural attenuation, and it has become apparent
that the extent of fractionation often increases over time, but
there is little quantitative information on the rates at which
the isotope fractionation proceeds.
In the present study, we conducted experiments to
investigate the H isotope fractionation of n-alkanes; in particular,
we focused on isotope fractionation rates during the
evaporation process because this subject has received relatively
little attention to date. The objectives of our studies were
(1) to apply CSIA to investigate the behavior of organics by
measuring the fractionation of H isotopes from n-alkanes and
(2) to develop a diagnostic tool for studying the environmental
attenuation of organic matter.