 The most common NMR techniques used when discriminating chiral compounds are 1H-NMR, 19F-NMR and 13C-NMR.1H-NMR is the primary technique used to assign absolute configuration.19F-NMR is almost exclusive applied to optical purity studies, and 13C-NMR is primarily used to characterize substrates that do not have protons that are directly bonded to an asymmetrical carbon atom.