In an acid medium of HCl, H₂SO₄ or HNO₃, bile salts, such as sodium taurocholate, sodium tauroglycocholate, sodium deoxycholate and cow sodium cholate, were able to self-aggregate to form large particles to produce new enhanced resonance Rayleigh scattering (RRS) signals. The RRS peaks were similar in the same medium for the four reaction products. But their spectral characteristics were a little different in the three media. The maximum RRS peak was at 349 (HNO₃), 359 (H₂SO₄) and 369 nm (HCl), respectively, while the intensity of ΔI_RRS was directly proportional to the concentration of bile salt in a certain concentration range. Their detection limits for the different kinds of bile salt systems are between 12.0～21.8 ng/mL. It was shown that this method has not only high sensitivity and good selectivity, but also simplicity and rapidity. It was applicable to the determination of the commercial bile salts and serum samples with satisfactory results. In addition, the reaction mechanism and the reasons for the enhancement of RRS were discussed.

Key words: sodium taurocholate, sodium tauroglycocholate, sodium deoxycholate, sodium cholate, resonance Rayleigh scattering spectrum