Fluorescence enhancement of the protein-curcumin-sodium dodecyl benzene sulfonate system and protein determination.

Protein can greatly enhance the fluorescence of curcumin (CU) in the presence of sodium dodecyl benzene sulfonate (SDBS). Experiments indicate that under the optimum conditions, the enhanced intensity of fluorescence is proportional to the concentration of proteins in the range of 0.0050-20.0 microg mL(-1) for bovine serum albumin (BSA), 0.080-20.0 microg mL(-1) for human serum albumin (HSA), and 0.040-28.0 microg mL(-1) for egg albumin (EA). Their detection limits (S/N = 3) are 1.4 ng mL(-1), 20 ng mL(-1), and 16 ng mL(-1), respectively. The method has been satisfactorily used for the determination of proteins in actual samples. In comparison with most of fluorimetric methods, this method is quick and simple, has high sensitivity and good stability. The interaction mechanism is also studied.