Determining Size and Concentration of Gold Nanoparticles via Ultraviolet-Visible Spectrophotometer

by Sanim Rahman

Submitted : Fall 2015

The concentration and size of gold nanoparticles (GNPs) that were produced through the Turkevich method were determined by utilizing the absorption at the Surface Plasmon Resonance (SPR) peak. By using a Perkin Elmer Lambda 35 UV/Vis spectrophotometer, the wavelength and absorption at the SPR peak were determined.

With the absorption, the concentration of GNPs suspended in solution was calculated through Beer-Lambert’s law. With the UV-VIS data, the average diameter of the GNPs in the solution was determined. The ratio of the absorption at the SPR peak and the absorption at 450 nanometers was used to calculate the average size of the produced gold nanoparticles. The recorded sizes were then compared to an SEM scan of the produced GNPs and values from Sigma-Aldrich.

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