Determination of Chitosan in Serum Albumin-Cu(II)-Chitosan Ternary System Using Resonance Rayleigh Scattering Spectra

In Britton-Robinson (B-R) buffer solution (pH 6.5), serum album (SA) and chitosan reacted with each other, and the resonance Rayleigh scattering (RRS) spectrum of the system seemed to be very weak. After adding Cu2+ to make the concentration ratio of Cu2+ to SA being 10:1, which would react to form a ternary complex, its RRS intensity was significantly enhanced. The enhanced intensity of RRS was directly proportional to the concentration of chitosan. In this study, the reaction conditions and the formation mechanism of the ternary complex of BSA (or HSA) with Cu2+ and chitosan were studied. The maximum RRS wavelengths are observed at 350 nm and 480 nm for BSA system, and at 340 nm for HSA system. The linear ranges and the detection limits are 0.01–4.0 g ml–1 and 3.66 ng ml–1 for BSA system, and 0.01–6.0 g ml–1 and 11.0 ng ml–1 for HSA. The RSD is less than 4.0%. It is obvious that the BSA system has a higher sensibility. So, a sensitive, simple, and fast method for the determination of trace amounts of chitosan by RRS technique has been developed. The influences of coexisting substances were investigated, and it is shown that the method has a good selectivity. This method has been applied for the determination of chitosan in hygienical capsule samples and self-made chitosan raw samples, and satisfactory results have been obtained.