Effect of Reducing Agent Type on the Morphology, Size, and Stability of Gold Nanoparticles (AuNPs): A Comparative Study of Sodium Citrate and Ethylenediaminetetraacetic Acid (EDTA)

Abstract

Gold nanoparticles (AuNPs) were successfully synthesized using two types of reducing agents (sodium citrate and EDTA) to investigate the effect of reducing agent type on the physicochemical properties of the resulting nanoparticles. The citrate-mediated synthesis yielded optimal results at pH 4 with the addition of 0.25 mL of 0.25% citrate solution, whereas the EDTA-mediated synthesis was optimal under the same pH conditions with 0.50 mL of 0.25% EDTA solution. Transmission Electron Microscopy (TEM) analysis revealed that citrate-AuNPs were spherical with an average size of 56 nm, while EDTA-AuNPs exhibited a hexagonal morphology with an average size of 27 nm. Furthermore, EDTA-AuNPs demonstrated superior stability during long-term storage compared to citrate-AuNPs. These results suggest that the type of reducing agent significantly affects the morphology, size, and stability of synthesized AuNPs.