High-resolution homonuclear 2D NMR of carbon-13 enriched metabolites and their mixtures

► 2D TOCSY spectra of 13C-labeled metabolites could be decoupled along both dimension. ► Indirect covariance processing of constant-time 2D NMR spectrum provides resolution enhancement. ► High-resolution 13C-13C TOCSY spectra of complex mixtures display reduced cross-peak overlaps.