[The high-sensitivity determination of protein concentration by the enhancement of resonance light scattering of chlorophenol red].

A new resonance light scattering (RLS) assay is presented in this paper. At the optimum pH = 4.0, the weak RLS of chlorophenol red can be greatly enhanced by the addition of proteins due to the interaction between protein and chlorophenol red. A new quantitative determination method for proteins has been developed. The linear range is 0-1.0 mg.L-1 for BSA, and 0-0.75 mg.L-1 for HSA with detection limit of 20.3 micrograms.L-1 for BSA, and 20.4 micrograms.L-1 for HSA, respectively. Besides high sensitivity, the method is characterized by good reproducibility, rapidity of reaction, good stability and few inferring substances. The determination results of the proteins in human serum samples by this method are very close to those obtained using biuret spectrophotometric method, with relative stand deviation of 1.17%-2.42%.