Nitrogen-doped Graphene Electrochemical Sensor for Selenium (IV) in Water

摘要

In this study, the electrochemical detection of Se(IV) on a glassy carbon electrode (GCE) modified withnitrogen-doped graphene (NG) is reported. NG was synthesized from graphene oxide (GO) by thermalannealing of GO in ammonia. Structural and morphological studies of the synthesized NG wereconducted using field emission scanning electron microscopy (FESEM), Raman spectroscopy, highresolution-transmission electron microscopy (HR-TEM), Fourier Transform -infrared spectroscopy (FT-IR) and a CHNS analyzer. Electrochemical characterization of the unmodified GCE and the NGmodified GCE (GCE-NG) was conducted using cyclic voltammetry (CV) and electrochemicalimpedance spectroscopy (EIS). The newly developed GCE-NG sensor demonstrated improvedelectrochemical properties when compared to the bare GCE. Square wave anodic stripping voltammetry(SWASV) was employed to optimize the proposed sensors’ detection parameters: 0.1 M HClO 4supporting electrolyte, -0.8 V deposition potential and 50 s deposition. The calibration graph of Se(IV)concentrations and current response demonstrated linearity during the calibration of the sensor in theconcentration range 1 – 120 ppb, with a limit of detection (LOD) of 0.092 ppb. The proposedelectrochemical sensor was applied in the analysis of real water samples and inductively coupled plasma-optical emission spectroscopy (ICP-OES) was used to validate the results.