Green synthesis of gold nanoparticles from Combretum indicum and their characterization

Abstract

Green synthesis of gold nanoparticles (AuNPs) facilitated by the use of an aqueous petal extract of the medicinal plant Combretum indicum (Madhumalti) as a bio-reducing agent has been performed in this work. In the absence of ammonia, the average diameter of synthesised gold nanoparticles ranged from 41nm to 79.40 nm whereas the range is 11.856 nm to 49.2 nm in the presence of ammonia. The formation of AuNPs is mediated by time that is monitored by Surface Plasmon behaviour using UV-Vis Spectroscopy at different stirring time intervals. The reaction shows a significant increase in absorbance with time with an absorbance peak in the range of 530-570 nm after one hour of stirring. Synthesis of nanoparticles is confirmed by the change of colour of auric chloride from yellow to dark brown. Synthesized AuNPs have been characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX).