Highly Selective Mercury Detection

Partially oxidized graphene flakes (po-Gr) were obtained from graphite electrode by an elec-trochemical exfoliation method. As-produced po-Gr flakeswere dispersed inwater with the assistance of poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonate) (PEDOT:PSS). The po-Gr flakes and the po-Gr/PEDOT:PSS nanocomposite (po-Gr/PEDOT:PSS) were charac-terized by Raman spectroscopy, Fourier transform-infrared spectroscopy (FT-IR), UV–Vis spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). In addi-tion, we demonstrated the potential use of po-Gr/PEDOT:PSS electrode in electrochemical detection of mercury ions (Hg2C) in water samples. The presence of po-Gr sheets in PEDOT:PSS film greatly enhanced the electrochemical response for Hg2C. Cyclic voltam-metry measurements showed a well-defined Hg2C redox peaks with a cathodic peak at 0.23V, and an anodic peak at 0.42V. Using differential pulse stripping voltammetry, detec-tion of Hg2C was achieved in the range of 0.2–14mM(R2 D0.991), with a limit of detection of 0.19mM for Hg2C. The electrode performed satisfactorily for sensitive and selective detection of Hg2C in real samples, and the po-Gr/PEDOT:PSS film remains stable on the electrode surface for repeated use.Therefore, our method is potentially suitable for routine Hg2C sensing in environmental water samples.