Using SEC for Analyzing the Sizes of Au/Pt Core/Shell Nanoparticles

This paper describes the use of size-exclusion chromatography (SEC) to characterize the sizes of fabricated Au/Pt core/shell nanoparticles (NPs), which were monitored using a polymer-based SEC column (pore size: ca. 400 nm) and a mobile phase of 10 mM sodium dodecyl sulfate (SDS). The plot of the retention time with respect to the logarithm of the size of the Au NPs was very linear (R ² = 0.999) for NP diameters falling in the range from 5.3 to 59.9 nm. The relative standard deviation (n = 5) of these retention times was less than 0.20%. When using SEC to analyze synthetic products, we found that the sizes of the fabricated Au/Pt core/shell NPs could be controlled via modification of the volumes of the seed, SDS, and sodium hydroxide solutions. A good correlation existed between the sizes determined through SEC and those determined using transmission electron microscopy. Thus, polymer-based SEC appears to be a useful technique for monitoring the sizes of NPs—and nanomaterials in general.