Abstract: The binding reactions of the dye Eosin Y with proteins have been studied. In the presence of SDS and in the citricacid-NaOH buffer medium （pH3.05）, the Eosin Y combined with the proteins by intermolecular forces to form complexes,causing an enhancement of resonance light scattering （RLS） at maximum wavelength of 365nm. A novel method for the determinationof proteins based on the enhancement of RLS was developed. The sensitivity raisesd 2.6 times in the presence of SDS. The linearranges were 0.05～3.7 mg/L for the bovine albumin and 0.105.6 mg/L for human γ-IgG. The detection limits were 12 and 18μg/L, respectively .The method has been applied to determine proteins in human serum, milk, soybean milk and protein, samplein urine. The results obtained with this method were in accordance with the authentic brilliant blue method.

Key words: resonance light scattering(RLS), Eosin Y, protein, sodium dodecanesulphonate(SDS)