posted on 2018-02-26, 00:00authored byRobert Evans, Guilherme Dal Poggetto, Mathias Nilsson, Gareth A. Morris
Diffusion-ordered
NMR spectroscopy (DOSY) is increasingly widely
used for the analysis of mixtures by NMR spectroscopy, dispersing
the signals of different species according to their diffusion coefficients.
DOSY is used primarily to distinguish between the signals of different
species, with the interpretation of the diffusion coefficients observed
usually being purely qualitative, for example to deduce whether one
species is bigger or smaller than another. In principle, the actual
values of diffusion coefficient obtained carry important information
about the sizes of different species and on interactions between species,
but the relationship between diffusion coefficient and molecular mass
is in general a very complex one. Here a recently proposed analytical
relationship between diffusion coefficient and molecular mass for
the restricted case of small organic molecules is tested against a
wide range of data from the scientific literature and generalized
to cover a range of solvents and temperatures.