Determination of microamounts of proteins by resonance light scattering with copper phthalocyanine tetrasulfonic acid

Based on the strong enhancement effect of proteins on the resonance light scattering of copper phthalocyanine tetrasulfonic acid, a method for the determination of microamounts of proteins has been developed. Under the experimental conditions (2.0 x 10(-6) mol/L copper phthalocyanine tetrasulfonic acid, pH 2.60, ionic strength 0.001 mol/L NaCl), the linear range of this assay is 0.06 - 4.0 mu g/mL for bovine serum albumin (BSA), 0.1 - 2.0 mu g/mL for human serum albumin (HSA), 0.0 - 2.0 mu g/mL for human gamma-IgG, and 0.2 - 6.0 mu g/mL for ovalbumin. The detection limits (3 delta) are 16.8 ng/mL for BSA, 23.4 ng/mL for HSA, 37.6 ng/mL for human gamma-IgG, and 48.3 ng/mL for ovalbumin, respectively. This method has been applied to the analysis of total proteins in human serum samples collected from the hospital, and the results were in good agreement with those reported by the hospital.