Thiols, compounds that contain sulfhydryl group, are powerful reducing agents capable of acting as antioxidants, enzyme cofactors, and neuromodulators. The SensoLyte® 520 Thiol Quantitation Assay Kit provides a convenient, highly sensitive fluorescent assay for measurement of thiol concentrations. The novel reagent supplied in the kit, upon reaction with thiols, generates fluorescence which can be easily detected at excitation/emission=490/520 nm. The assay has a linear range of 0.04-160 µM thiol. Kit Size: 500 assays (96-well plate).