title: Suppressing exchange effects in diffusion-ordered NMR spectroscopy.
abstract: In diffusion-ordered spectroscopy (DOSY) the aim is to separate signals from different molecular species according to their different diffusion coefficients. Each species has its individual diffusion coefficient (that may accidentally coincide with that of another species, e.g. if they are of very similar size). In exchanging systems, however, there is a serious complication in that the apparent diffusion coefficient of an exchanging signal will be a compromise that depends, among other factors, on the diffusion coefficients of the exchange partners and the rate of exchange between them. The DOSY spectrum will be much harder to interpret and can often give the appearance of extra (spurious) components in the mixture. Here a new and surprisingly simple experiment is described that suppresses the effects of exchange on apparent diffusion coefficients, restoring the simplicity of interpretation enjoyed by non-exchanging systems.
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom. Electronic address: j.a.aguilar@durham.ac.uk.
authors.forename: Juan A
authors.initials: JA
authors.lastname: Aguilar
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom. Electronic address: ralph.adams@manchester.ac.uk.
authors.forename: Ralph W
authors.initials: RW
authors.lastname: Adams
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom; Dept. of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark. Electronic address: mathias.nilsson@manchester.ac.uk.
authors.forename: Mathias
authors.initials: M
authors.lastname: Nilsson
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom. Electronic address: g.a.morris@manchester.ac.uk.
authors.forename: Gareth A
authors.initials: GA
authors.lastname: Morris
keywords: Chemical exchange; DOSY; Diffusion; Spin echo