Suppression of 13C satellites in 1H DOSY spectra

Abstract

Diffusion-ordered spectroscopy (DOSY) is a valuable tool for the analysis of intact mixtures, since it can separate the signals of components according to their apparent diffusion coefficients. However, DOSY experiments are acutely sensitive to spectral quality, and especially to signal overlap, which can lead to misleading apparent diffusion coefficients. Here, we introduce a new NMR experiment to reduce signal overlap in mixtures with a wide range of concentrations, by removing one-bond ¹³C satellites. In such high dynamic range mixtures, ¹³C isotopomer signals from major components can overlap with signals from minor components, causing problematic distortions in the diffusion domain of a DOSY spectrum. The new method, Oneshot-iDISPEL, is a combination of the Oneshot and DISPEL experiments, and its performance has been demonstrated on a Greek alcoholic beverage, ouzo, which contains small amounts of anise flavour components and sucrose. Ethanol is a major component, and the suppression of its ¹³C satellites reduces signal overlap with minor components, offering significant improvement in DOSY spectra.

Keywords: (13)C satellites; DISPEL; DOSY; Diffusion; NMR; Oneshot; Ouzo.