Selective colorimetric sensing of Zn(II) ions using green-synthesized silver nanoparticles: Ficus benjamina extract as reducing and stabilizing agent

Abstract In this paper, we present a greener synthesis of silver and gold nanoparticles using an aqueous extract of Ficus benjamina leaves. The metal nanoparticles were synthesized via conventional heating and microwave-assisted methods using the aqueous extract as reducing and capping agent. It was observed that the use of a Ficus benjamina leaf aqueous extract via microwave-assisted heating represent a faster, greener and easier method than a conventional heating procedure for the synthesis of silver and gold nanospheres, also leading to narrower nanoparticle size. The sensing characteristics of the microwave-assisted silver nanoparticles were evaluated for the specific determination and semiquantification of Zn(II) ions. The colorimetric semiquantification of Zn(II) ions was achieved by UV–vis spectroscopy, using an empirical model in a concentration range between 0.2 and 2.0 mM, reaching total precipitation at concentrations higher than 2.0 mM.