[Study on the spectra of Cal-Red-Cu(II) complex with bovine serum albumin and its analytical application]

The Resonance light scattering (RLS) spectra, fluorescence spectra, and absorption spectra of Cal-Red-Cu(II) metal complex with bovine serum albumin (BSA) were studied. As the Cal-Red-Cu(II)-BSA complex formed, the RLS spectra and fluorescence spectra enhanced, but the absorption spectra weakened and the absorption peak at 594 nm disappeared. At pH 5.65-5.75, the enhanced RLS of Cal-Red-Cu(II) metal complex with BSA system was characterized by the maximum scattering at 317 nm, and the RLS intensity is proportional to the concentration of BSA. Under optimal conditions, the linear range of calibration was 0.75-10 microg x mL(-1), the linear regression equation was I=150. 88+201.48c(BSA, microg x mL(-1))with r=0.9973, and the limit of detection was 5.62 x 10(-2) microg x mL(-1). The method was applied to the determination of BSA in synthetic samples satisfactorily. A mechanism of electrostatic force was suggested for the interaction between BSA and Cal-Red-Cu(II).