Preparation, optical characterization and stability of gold nanoparticles by facile methods

The influence of synthesis method, cycles quantity and sonication time in the gold nanoparticles size and plasmon resonance were analyzed to establish the synthesis with smaller nanoparticle size and higher absorbance. Gold nanoparticles were analyzed by UV-Vis spectrophotometry, dynamic light scattering (DLS) and surface electron microscopy (SEM). The results indicate that the nanoparticles obtained by microwave have bigger size but higher absorption. These nanoparticles were analyzed one year after its synthesis and it was found that the plasmon resonance signal remains almost unchanged. Finally, two equation were derived from the analyzes for estimate molar extinction coefficient, molar concentration and nanoparticle average diameter.