Highly efficient size separation of CdTe quantum dots by capillary gel electrophoresis using polymer solution as sieving medium

Abstract

In this paper, we present a new method for highly efficient size separation of water-soluble CdTe quantum dots (QDs) based on CGE using polymer solution as sieving medium. CdTe QDs were synthesized in aqueous phase by a chemical route with mercaptopropionic acid as a ligand. In the alkaline solution, CdTe QDs possess negative charges and migrate to the anode in the electric field. In linear polyacrylamide sieving medium, the migration time of CdTe QDs was increased with the size of CdTe QDs. The effects of some factors, such as types, concentrations, and pH of sieving media, on the separation of CdTe QDs were investigated systematically. Highly efficient separation of CdTe QDs was obtained in linear polyacrylamide sieving medium, and collection of fractions was automatically accomplished by CGE technique. Our preliminary results show that CGE technique is an efficient tool for characterization and size-dependent separation of water-soluble nanoparticles. In addition, the fraction collection in CGE may be useful in certain special applications such as fabrication of nanodevices in the future.

Nanomaterials in fluorescence-based biosensing

“…Successful separations of gold/silver nanoparticles or QDs based on their sizes or surface charges have been achieved using slab-gel electrophoresis, isoelectric focusing, or capillary electrophoresis (CE) [96][97][98][99][100][101][102]. While the slab-gel technique provides the ability to collect the purified nanoproducts, CE offers fast separation speed and low sample consumption, allowing in situ monitoring of the synthesis process for better product quality control.…”

Application of capillary zone electrophoresis for separation of water‐soluble gold monolayer‐protected clusters

“…For instance, it has been employed to separate Au [32,33,35,38,39,43], Ag [40,42], Au/Ag (core/ shell) [46], silicate nanoparticles [37], latex and polystyrene particles [29,30,36,44], and other metal oxides particles [31,34]. However, most of them were focused on the separation of larger core nanoparticles (diameter .5 nm) [29-34, 36-42, 44, 46] rather than MPCs, or the mixture [29-31, 34, 36, 37, 41]/two-component mixture [38,39,44,47] of commercial available nanoparticles rather than real sample of polydisperse product of nanoparticles, or separation of a polydisperse product of nanoparticle with poor resolution [32,33,35,[40][41][42]. In addition, the migration order of nanoparticles in CZE with bare capillary in some reports is quite contradicting whilst some claimed that the earlier-migrating peak was the larger core-size nanoparticles [32,33,36] and others suggested it was the smaller ones [29, 30, 37-39, 41, 42, 46, 47].…”

“…Electrophoretic separation of micrometer-and nanometer-sized particles by gel electrophoresis [26][27][28], continuous free-flow electrophoresis [2], CZE [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46], and CGE [47] have been reported. Although the first two methods were successful in isolating the monodisperse product, online monitoring was impossible for both.…”

Investigation of the size–property relationship in CuInS2quantum dots

“…Therefore, post-processing steps are necessary to narrow the PSD. Possible techniques for size fractionation are gel electrophoresis, 17,18 exclusion chromatography, 19 reversed micelle preparation, 20 size-selective precipitation (SSP) [21][22][23] or flow-field fractionation (FFF). [24][25][26] Detailed summaries of techniques used for separation of nanoparticles by their size and/ or shape are provided in reviews by Kowalczyk 27 and Mori.…”