Spectral anion sensing and γ-radiation induced magnetic modifications of polyphenol generated Ag-nanoparticles

• Polyphenols obtained from peanut skin extract have been used for the bio-synthesis of silver nanoparticles.
• Effect of low dose γ irradiation during the synthesis was studied.
• Variable time exposure to γ-irradiation results in an exponential decay of ferromagnetic component.
• A freshly prepared AgNP shows selective spectral changes towards trace I− among a series 16 other competing anions.

A fast one step bio-synthesis for in situ preparation of silver nanoparticles is proposed. The method involves reduction of AgNO3 with an aqueous extract of peanut skin, which is a good source of polyphenols. The silver nanoparticles thus synthesized were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), UV–Vis absorption spectroscopy, Fourier Transform infrared (FTIR) spectroscopy and magnetic measurements. Effect of low dose γ irradiation during the synthesis was studied and their physico-chemical properties were compared with those produced without irradiation. On the contrary to the diamagnetic behavior of bulk silver, the silver nanoparticles thus prepared show a significant ferromagnetic moment component. Variable time exposure to γ-irradiation results in an exponential decay of ferromagnetic component. A freshly prepared solution of silver nanoparticles shows selective spectral changes towards iodide ions at trace concentration (below 50 μM) among a series of 16 other competing anions. The prepared nanoparticles are therefore suitable for anion sensing application.

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