Determination of proteins by fluorescence quenching of erythrosin B

Erythrosin B (EB) binding to proteins causes a decrease in the fluorescence maximum of EB at 550 nm. Based on this, a new, fast and simple fluorescence quenching method for the determination of proteins is developed. The linear range of this assay is 1.36–20.4 μg ml−1. The method has very few interferences, most of which can be minimized by dilution. In the detection of proteins in human serum, this method gave values close to that of the Coomassie brilliant blue method.