Study on the Resonant Scattering Spectrum of the Protein-Bromothymol Blue System and Its Analytical Application

A new method for the determination of protein was described in this paper,based on the enhancement of intensity of resonant scattering spectrum of bromothymol blue by protein. The increase of magnitude of the intensity was found to keep linear relationship with the concentration of protein in the ranges of 0.04-2.4,0.04-2.4,0.04-1.6 and 0.04-1.8 mg·L-1 for human serum albumin,bovine serum albumin,human γ-immunoglobulin and ovalbumin respectively,with their corresponding detection limits of 23.9,23.0,25.0 and 30.4 μg·L-1. The measurements were made at the wavelength of 365 nm. In the application of this method to the determination of total protein in human serum and urine samples,RSD′s (n=6) obtained were 1.5% and 3.3% respectively,and the results were in consistency with the results obtained by the method of CBB G-250.