Resonance light scattering technique for the determination of protein with rutin and cetylpyridine bromide system

A new resonance light scattering (RLS) assay of protein is presented. In Tris-NaOH (pH = 10.93) buffer, the RLS of rutin-cetylpyridine bromide (CPB) system can be greatly enhanced by protein, including bovine serum albumin (BSA) and human serum albumin (HSA). The enhanced RLS intensities are in proportion to the concentration of proteins in the range of 5 × 10−9 to 2.5 × 10−6 g ml−1 for BSA and 2.5 × 10−8 to 3.5 × 10−6 g ml−1 for HSA. The detection limits (S/N = 3) are 3.0 ng ml−1 for BSA and 10.0 ng ml−1 for HSA. Samples are determined satisfactorily.