Capillary electrophoretic separation and characterizations of CdSe quantum dots

Abstract

We have developed a capillary electrophoresis method to characterize the QD surface ligand interactions with various surfactant systems. The method was demonstrated with 2-5 nm CdSe nanoparticles surface-passivated with trioctylphosphine oxide (TOPO). Water solubility was accomplished by surfactant-assisted phase transfer via an oil-in-water microemulsion using either cationic, anionic, or non-ionic surfactants. Interaction between the QD surface ligand (TOPO) and the alkyl chain of the surfactant molecule produces a complex and dynamic surface coating that can be characterized through manipulation of CE separation buffer composition and capillary surface modification. Additional characterization of the QD surface ligand interactions with surfactants was accomplished by UV-VIS spectroscopy, photoluminescence, and TEM. It is anticipated that studies such as these will elucidate the dynamics of QD surface ligand modifications for use in sensors. © 2010 Versita Warsaw and Springer-Verlag Wien.