Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Determining the core, corona, and total size of CdSeS/ZnS quantum dots by SEC/QELS and TEM



Leena M. Pitkanen, Andre Striegel


The size (hydrodynamic or Stokes radius, RH) of non-functionalized CdSeS/ZnS (core/shell) quantum dots (QDs) was characterized by size-exclusion chromatography with on-line quasi- elastic light scattering (SEC/QELS). Accurate determination of the size of QDs is important, because many of the optical properties of these materials are size dependent. A clear advantage of SEC/QELS over many batch techniques (e.g., QELS without separation) is the capability of the hyphenated technique to characterize the entire size range of a polydisperse sample, rather than merely providing a statistical average of the sizes present in the sample. Here, the SEC/QELS-determined RH values of CdSeS/ZnS QDs are compared to those determined by a traditional SEC experiment employing a polystyrene calibration curve, providing for the first reported study on SEC/QELS of non-functionalized QDs while also demonstrating the shortcomings of the popular calibration curve approach. Furthermore, combining the RH of the QDs obtained by SEC/QELS with core size measurements derived from transmission electron microscopy allowed further calculation of the size of the QDs' coronas. The latter result was found to be in close agreement to the previously measured dimension of the main corona constituent, as well as with the calculated size of this constituent.
Analytical and Bioanalytical Chemistry


quantum dots, size-exclusion chromatography, quasi-elastic light scattering, hydrodynamic radius, transmission electron microscopy, core and corona dimensions


Pitkanen, L. and Striegel, A. (2016), Determining the core, corona, and total size of CdSeS/ZnS quantum dots by SEC/QELS and TEM, Analytical and Bioanalytical Chemistry, [online],, (Accessed April 12, 2024)
Created May 20, 2016, Updated October 12, 2021