| Abstract: | A new resonance light scattering (RLS) probe for determining proteins is presented. The weak RLS of pyronine Y–SDS can be enhanced substantially by adding proteins in the presence of H2SO4, resulting in a strong and wide RLS band in the region 310–425 nm. The interaction of pyronine Y–SDS with proteins was studied on the basis of this behavior and a new quantitative method was developed for determining proteins. The enhanced RLS intensity is proportional to the concentration of proteins in the range 0.15–3.6 μg mL−1 for bovine serum albumin (BSA) and 0.06–4.8 μg mL−1 for human serum albumin (HSA), with detection limits of 21.0 and 12.0 ng mL−1, respectively. This method is characterized by high sensitivity, rapidity of reaction, and simplicity. Four synthetic samples were determined satisfactorily and recovery was 99.5–101.5%. Results for human serum and urine samples were in agreement with those obtained by the Bradford method, with relative standard deviations (RSD) of 1.5–3.1%. |
