An engineered nanocomposite for sensitive and selective detection of mercury in environmental water samples

Abstract

We report on a novel carbon-based nanocomposite made of reduced graphene oxide/titania nanotubes (RGO/TNT) with excellent conductivity and absorptivity for the sensitive electrochemical determination of Hg(II) as a water pollutant. Field emission scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction, FTIR spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy were used to characterize the morphological, structural, and electrochemical properties of the fabricated modifier. Square wave anodic stripping voltammetry was applied for the analytical measurements. The parameters influencing the peak current response were studied and optimized. The linear response of detection toward Hg(II) was found to be in the range of 2.5 × 10⁻¹⁰–5 × 10⁻⁶ M with a high regression coefficient (0.999). The limit of detection was found to be 4 × 10⁻¹¹ M. The investigated sensing platform was tested for Hg(II) simultaneously in the presence of Cu(II) and Mn(II) and proved to have high sensitivity, selectivity, and reproducibility. Finally, the modified electrode was used for the trace level detection of Hg(II) in real environmental water samples, showing promising results.