Determination of proteins in serum by fluorescence quenching of rose bengal using the stopped-flow mixing technique.

The stopped-flow mixing technique was used to develop a very fast, sensitive and accurate method for determining total proteins. The method is based on the lower fluorescence of Rose Bengal caused by binding of the dye to the proteins. The decrease in the fluorescence intensity, measured at 572 nm with excitation 555 nm, was linearly related to protein concentration from 1.3 to 24.5 micrograms ml-1. The detection limit was 0.3 microgram ml-1. The method was satisfactorily applied to the determination of total proteins in different serum samples.