Absorption Spectrometric Study on the Reaction System of Ce(Ⅲ) and HSA and Its Analytical Application

In a B-R buffer medium of pH 2.0-3.0, a blue colored coordination complex was formed by the reaction of p-acetyl-carboxyazo (p-ACA) with Ce(Ⅲ), having values of absorption maxima of the complex and the reagent p-ACA at wavelengths of 727 nm and 577 nm respectively. Upon additon of definite amount of human serum albumin (HSA) to the reaction system, color-fading was observed, leading to derease in absorbance as measured at 727 nm. It was found that linear relationship was kept between the magnitude of decrease in absorbance (ΔA) and mass concentration of HSA in the range of 10-120 mg·L-1. Apparent molar absorptivity of the reaction system in respect to HSA found was 5.14×105L·mol-1·cm-1. TX-100 solution was added to raise the sensitivity of the reaction system 45% higher. The above procedure was applied to the analysis of 3 human serum samples, giving values of HSA in consistency with the results obtained by the method of CBB G250.