Analytical Sciences

Resonance Light Scattering Spectroscopy of β-Cyclodextrin-Sodium Dodecylsulfate-Protein Ternary System and Its Analytical Applications

Zhanguang CHEN,* Jinbin LIU,* Xiaoming CHEN,** Taiyu ZHANG,* and Yali HAN*

*Department of Chemistry, Shantou University, Shantou 515063, P. R. China
**Institute of Chemistry, Xiangtan University, Xiangtan 411105, P. R. China

A simple, highly sensitive and dye-less assay for proteins was reported using a resonance light-scattering (RLS) technique based on the enhanced RLS intensity of β-cyclodextrin (β-CD)-sodium dodecylsulfate (SDS)-protein system. Under the optimum conditions, the enhanced RLS intensity is in proportion to the concentration of proteins in the range of 0.01 to 2.3 µg ml^-1 for bovine serum albumin (BSA), 0.01 to 2.0 µg ml^-1 for human serum albumin (HSA), 0.015 to 5.0 µg ml^-1 for γ-globulin (γ-G), 0.02 to 3.5 µg ml^-1 for egg albumin (EA), 0.02 to 4.0 µg ml^-1 for pepsin (Pep), and 0.02 to 3.6 µg ml^-1 for α-chymotrypsin (Chy). Their detection limits (S/N = 3) are 1.1, 1.6, 2.4, 6.7, 5.4 and 4.2 ng ml^-1, respectively. Synthetic samples and human serum samples were determined satisfactorily, and the results were in reasonable agreement with those obtained by a documented spectrophotometric (Bradford) method.

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