Analytical Sciences


Abstract − Analytical Sciences, 23(3), 331 (2007).

Determination of Lysozyme at the Nanogram Level by a Resonance Light-Scattering Technique with Functionalized CdTe Nanoparticles
Juan LI,* Xi-Wen HE,* Yun-Li WU,* Wen-You LI,* and Yu-Kui ZHANG*,**
*Department of Chemistry, Nankai University, Tianjin 300071, China
**National Chromatographic Research & Analysis Center, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian 116011, China
Nanoparticles of cadmium telluride coated with mercaptoacetic acid were prepared in the water phase. Further, an assay of lysozyme with a sensitivity at the nanogram level is proposed. At pH 7.28, lysozyme with positive charges can interact with CdTe nanoparticles. The resonance light-scattering (RLS) signals of functionalized nano-CdTe were greatly enhanced by lysozyme in the region of 300 - 600 nm, characterized with peaks located at 367, 470 and 533 nm. A linear relationship could be established between the enhanced RLS intensity and the lysozyme concentration in the range of 0.06 - 4.0 µg mL-1. The limit of detection was 9.5 ng mL-1. The contents of lysozyme were determined with recoveries of 95.6 - 104.8% and RSD of 1.5 - 2.3%, respectively. This method is sensitive, rapid, accurate and simple, and provides a new and reliable means for the quantity determination of lysozyme.