One common route is the reduction of HAuCl4 to gold ions.
First used by Turkevitch in the early 1950s to produce gold nanospheres using sodium
citrate as a reducing agent4,5 , the reduction method has been adapted by
numerous researchers to synthesize nanoparticles of various sizes5
It was initially used to synthesize isotropic nanoparticles approximately 15 nm in
diameter, the procedure involves the reaction4-5
: