Optical photos of the obtained gold colloids, the diluted samples and their corresponding UV-vis spectra. (A) Photos of gold colloids prepared from a solution of 0.25 mM to 2.0 mM HAuCl4 3H2O (corresponding to 0.1 mg/ml to 0.8 mg/ml, respectively) and their diluted samples at a content of 0.25 mM Au. (B) The corresponding UV-vis spectra of the diluted samples. (Baseline was adjusted artificially).
Li et al. Nanoscale Research Letters 2011 6:440 doi:10.1186/1556-276X-6-440