Goethite (α-FeOOH) nanoparticles wrapped on reduced graphene oxide nanosheet for sensitive electrochemical detection of arsenic(III)

The goethite (alpha-FeOOH) nanoparticles were wrapped on the reduced graphene oxide (rGO) to synthesize the alpha-FeOOH/rGO nanocomposites. The nanocomposites (NCs) were initially examined for their optical, structural, and morphological properties. The XRD data obtained the crystallite size of the alpha-FeOOH, showed that the average crystal size for pristine alpha-FeOOH and alpha-FeOOH/rGO nanocomposites were about 85 and 90 nm, respectively. The transmission electron microscope confirmed the nanoparticles (NPs) were evenly distributed throughout the reduced graphene oxide sheets. The nanocomposites improved glassy carbon electrodes (GCE), making them efficient sensors for detecting the arsenic(III) (As+3) in a pH 5 phosphate buffer solution with an Ag/AgCl reference electrode. The detection limit for As+3 was 0.07 mu gL-1 and the resulting sensitivity was 0.39 mu A-1 mu gL-1 in the linear dynamic range of 0.1-10 mu gL-1. The alpha-FeOOH/rGO/GCE was more sensitive than its original and showed a synergistic effect due to the influence of alpha-FeOOH on the properties of rGO. The alpha-FeOOH/ rGO NCs-modified GCE electrode performed as a promising sensor, by separating the common interfering ions. Moreover, the modified electrode exhibited remarkable stability, repeatability, and potential real-time appli-cation towards the detection of arsenic(III). Additionally, the proposed approach has been successfully applied to the detection of As+3 in the real water sample.