The work exploits use of eco-friendly method to synthesis GNPs and tuning the optimum parameters using juice of Citrus lemon. The optimum yield of gold nanoparticles (GNPs) was obtained when 100 ppm aurochlorate was treated with lemon extract at pH 2.5 and heated it to 1000C. The results were verified using UV-Vis spectroscopy, XRD and Transmission electron microscopy. The GNPSs were monodisperse and found to be 10-100 nm in size. The stability of the GNPs synthesised using biological protocols was found to be extremely high then the chemically synthesised GNPs when tested with 5M NaCl solution. The reason for high stability can be partly attributed to the encapping of GNPs with citrate.
