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, sensitiv e and accurate method for determining total proteins. The method is based o n 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 w ith excitation 555 nm, was linearly related to protein concentration from 1 .3 to 24.5 mu g ml(-1). The detection limit was 0.3 mu g ml(-1). The method was satisfactorily applied to the determination of total proteins in diffe rent serum samples.