Chemical synthesis of gold nanoparticles using fluoroquinolone and their characterizations

We report synthesis of water-soluble gold nanoparticles (Au-NPs), having an average diameter of ca. 20 nm, by reducing AuCl3 using ciprofloxacin (CF) as a reducing/stabilizing agent. The synthesized Au-NPs have been characterized by scanning electron microscopy (SEM), EDS, TEM, UV-visible spectroscopy, X-ray diffraction and cyclic voltammetry. TEM and SEM combined with EDS confirmed that spherical shaped Au-NPs were formed. Uv-vis spectra of Au-NPs show two absorption bands corresponding to the capping agent ciprofloxacin and surface plasmon absorption bands at 274 nm and 535 nm, respectively. The Au-NPs are used to modify a glassy carbon electrode (GCE) and it's electrochemical and electrocatalytic properties are investigated. The Au-NPs show excellent electrocatalytic activity toward the oxidation of methanol at +0.33 V in alkaline solution, which was not observed on unmodified GCE. Further, Au-NPs modified electrode showed excellent electrocatalytic properties for reduction of oxygen at lower potential. Here, CF was used as a reducing agent to synthesis of Au-NPs. The synthesized Au-NPs are highly stable, can be stored for more than three months in air at room temperatures.