This is a great review showcasing the capabilities of DNP-enhanced NMR spectroscopy for metabolomic studies.
Jones, Oliver A. H. “Illuminating the Dark Metabolome to Advance the Molecular Characterisation of Biological Systems.” Metabolomics 14, no. 8 (August 2018).
Background The latest version of the Human Metabolome Database (v4.0) lists 114,100 individual entries. Typically, however, metabolomics studies identify only around 100 compounds and many features identified in mass spectra are listed only as ‘unknown compounds’. The lack of ability to detect all metabolites present, and fully identify all metabolites detected (the dark metabolome) means that, despite the great contribution of metabolomics to a range of areas in the last decade, a significant amount of useful information from publically funded studies is being lost or unused each year. This loss of data limits our potential gain in knowledge and understanding of important research areas such as cell biology, environmental pollution, plant science, food chemistry and health and biomedical research. Metabolomics therefore needs to develop new tools and methods for metabolite identification to advance as a field.