a, After sample preparation, small molecules, with the addition of chiral derivatization reagents (CDRs), can be enantiomerically resolved using nuclear magnetic resonance (NMR) spectroscopy. The intensity between d and l peaks on the NMR spectrum reflects the enantiomeric excess. b, After sample preparation, enzymatic probes with enantiomeric selectivity are added to samples to form conjugated molecules. Fluorescent imaging of a colorimetric assay is used to determine the concentration of the targeted enantiomers. H0, magnetic field.