Effect of reaction time and stability properties of gold nanoparticles synthesized by p-aminobenzoic acid and p-aminosalicylic acid

Abstract

In this work, we determined the influence of reaction time in the synthesis of gold nanoparticles (AuNPs) by p-aminosalicylic acid and p-aminobenzoic acid as reducing agents. Besides working as a reducing agent, the p-aminobenzoic acid and p-aminosalicylic acid also simultaneously played a role as a capping agent/stabilizing agent. Gold ions were first mixed with the pH adjusted p-aminobenzoic acid and p-aminosalicylic acid. The mixture was then heated in boiling water at 86 °C. The formation of AuNPs was indicated by the appearance of red color and analyzed with UV/Vis spectrophotometry to evaluate their surface plasmon resonance (SPR) absorption in the wavelength range of 400–800 nm. The reducing ability of the reducing agents was affected by its structure. Gold nanoparticles that were synthesized with p-aminosalicylic acid were more stable, formed faster and had a smaller size than its counterpart that were synthesized with p-aminobenzoic acid. The stability test over a period of 5 months showed that the AuNPs were relatively stable.