Fluorescence analysis of thiols with ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulphonate

Abstract

The fluorigenic reaction of thiols with ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulphonate (SBD-F) and the factors that affected the fluorescence of SBD-thiols were investigated. High pH, high temperature and organic solvents increased the reaction rates. The fluorescence intensity of the fluorophore was dependent on pH. Under suitable conditions (at pH 9.5 and 60 °C for 1 h), the detection limits for thiols such as cysteine, glutathione, captopril and bovine serum albumin were in the range 43–520 pmol ml^–1. The fact that blue shifts of the fluorophore were observed depending on the hydrophobicity of the added solvents indicated the possibility of its use for the environmental analysis of reactive thiols of macromolecules with SBD-F.