Biosynthesis of Silver Nanoparticles Using Leaves of Acacia Melanoxylon and their Application as Dopamine and Hydrogen Peroxide Sensors

In this work, we described a cost-effective and environmentally friendly technique for green synthesis of colloidal silver nanoparticles from aqueous extract of fresh leaves of Acacia melanoxylon and its application as a dopamine and hydrogen peroxide sensor. The prepared silver nanoparticles were characterized by UV-Visible absorption spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta-potential analysis, thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), etc. This method was found to be cost-effective, eco-friendly when compared to that of chemical and physical methods of nanoparticle synthesis. Silver nanoparticles modified carbon paste electrode (CPE) was fabricated for the detection of dopamine and hydrogen peroxide. The fabricated electrode showed an excellent sensitivity towards the oxidation of both dopamine (DA) and hydrogen peroxide (H2O2) in 0.1M phosphate buffer (PBS) solution at a pH 7. The effect of the scan rate, the concentration of the modifier and the analyte were studied by the cyclic voltammetric technique. The result exhibits good electrocatalytic activity, diffusion-controlled process and linear increase in peak current with different concentrations of dopamine and hydrogen peroxide.