Fenitrothion sensing with reduced graphene oxide decorated fumed silica nanocomposite modified glassy carbon electrode

Abstract

In this study, a nanocomposite was prepared via reducing graphene oxide on fumed silica (FS) surface to develop a modified electrode for the determination of fenitrothion (FNT). Reduced graphene oxide (RGO) decorated FS (FS@RGO) was used to modify glassy carbon (GC) electrode. The modified electrode decreased the overpotential of FNT (80 mV) and increased prominently the reduction peak current of FNT (9 times). Scanning electron microscopy, energy dispersive X-ray, X-ray diffraction and Raman spectroscopy analyses revealed that the FS@RGO nanocomposite was successfully synthesized. The presence of FS on FS@RGO structure prevented the agglomeration and allowed the homogeneous distribution of the nanocomposite in water, which was a drawback for RGO. Moreover, the presence of FS brings additional functionality to FS@RGO nanocomposite, which increases the adsorption and electron transfer rate of FNT. The GC/FS@RGO electrode showed a linear response in a wide range of FNT concentration (0.005-1.0 mu M) and a very low limit of detection (0.00019 mu M). The performance of the GC/FS@RGO electrode was evaluated by performing recovery studies in river water, urine, raisin extract, tomato extract and orange extract. Acceptable recovery values between 92.3% and 112.2% were obtained during the analysis of FNT-spiked samples.