Shape separation of nanometer gold particles by size-exclusion chromatography

The shape separations of suspended gold nanoparticles were investigated using size-exclusion chromatography. The separations in shapes were identified by examining the 3-D chromatograms obtained by employing a diode-array detection system and were further confirmed by analyzing TEM images of fractional collection of particles. This shape separation was achieved by adding a mixed-surfactant system containing sodium dodecyl sulfate and poluoxyethylene (23) dodecanol (Brij-35) into the eluent, which apparently affects the adsorption behaviors of both rodlike and spherical Au nanoparticles onto the column packing materials. While the overall particle gross sizes of these two shapes were similar, the baseline resolution was unfortunately not obtainable. However, the absorption spectra from the diode-array detector could be utilized to interpret the shapes of Au nanoparticles. The potential capability for the size separation of Au nanoparticles by size-exclusion chromatography with diode-array detection was also demonstrated.