Fluorescent microplate analysis of amino acids and other primary amines in soils

► We adapt a common fluorescent amino acid assay for use on 96-well microplates. ► Reducing incubation from 1 min to 1 h improves microplate performance of assay. ► The assay is able to determine leucine standard concentrations as low as ∼0.5 μM. ► The assay measures a broader range of soil compounds than previously assumed.