Lab Report
Lab Report Summary of the data collected
Our gold colloid solution Performed by Dr. Geoff Waterhouse, senior lecturer for the School of Chemical Sciences at the University of Auckland
The Transmission electron microscopy analysis
indicates that the majority of the gold colloids are of size less than 10 nm (< 10 nm). Overall, the colloid solution appears very stable and the colloids free from aggregation. Transmission Electron Microscopy (TEM) TEM analysis was used to evaluate the size and shape of the gold colloids. A selection of TEM images taken at different magnification is shown below. The size of the gold colloids can be determined by comparison with the scale bar on each image. Most colloids have a diameter of < 10 nm (~ 5 nm); very few particles show to be slightly larger (~ 15 to 20 nm in size). The gold colloids are of spherical or elliptical shape.
V –Visible Absorbance Spectroscopy
The gold colloid solution showed an absorption band at 522 nm, which is typical for gold colloids of size less than 20 nm. This absorption band is the green part of the visible spectrum, and hence the gold solution appears red when viewed under white light (i.e. we see the other wavelengths of the visible light not absorbed by the gold colloid solution).