‘Reversed Turkevich’ method for tuning the size of Gold nanoparticles: evaluation the effect of concentration and temperature

In this study the influence of dicarboxy acetone (DCA), as an oxidation product of sodium citrate, was evaluated by ‘inversed Turkevich’ method. Gold nanoparticles (GNPs) were synthesized systematically at various sodium citrate to HAuCl4 molar ratio and temperature. The GNPs were characterized by UV-vis spectroscopy, DLS and TEM techniques. According to the results, GNPs were obtained in range of 12-51 nm by inverting the reagents addition order. All of GNPs samples were monodisperse and had the same pattern of narrow size distribution in contrast to traditional Turkevich method in which GNPs larger than 40 nm became unstable. Moreover, molar ratio of Sodium citrate to HAuCl4 and temperature had a significant role in size controlling and monodispersity of GNPs. By increasing sodium citrate to HAuCl4 molar ratio, the size of GNPs reduced drastically. Since, temperature had a central role on the production rate of DCA, its influence on monodispersity of GNPs was more considerable than their size.