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dc.contributor.advisorJahed, N.
dc.contributor.advisorIwuoha, Emmanuel
dc.contributor.authorPokpas, Keagan William
dc.date.accessioned2016-03-29T13:13:00Z
dc.date.available2016-03-29T13:13:00Z
dc.date.issued2013
dc.identifier.urihttp://hdl.handle.net/11394/4829
dc.description>Magister Scientiae - MScen_US
dc.description.abstractElectrochemical platforms were developed based on pencil graphite electrodes (PGEs) modified with electrochemically deposited graphene (EG) sheets and Nafion-graphene (NG) nanocomposites in conjunction with an in situ plated bismuth-film (EG-PG-BiE and NG-PG-BiE). The EG- and NG-PG-BiEs were used as sensing platforms for determining Zn2+, Cd2+ and Pb2+ by square wave anodic stripping voltammetry (SWASV). EG sheets were deposited onto pencil graphite electrodes by cyclic voltammetric reduction from a graphene oxide (GO) solution, while a dip coating method was used to prepare the NG-PG-BiE. The GO and graphene, with flake thicknesses of 1.78 (2 sheets) and 2.10 nm (5 sheets) respectively, was characterized using FT-IR, HR-SEM, HR-TEM, AFM, XRD and Raman spectroscopy. Parameters influencing the electroanalytical response of the EG-PG-BiE and NG-PG-BiE such as, bismuth ion concentration, deposition potential, deposition time and rotation speed were investigated and optimized. The EG-PG-BiE gave well-defined, reproducible peaks with detection limits of 0.19 μg L-1, 0.09 μg L-1 and 0.12 μg L-1 for Zn2+, Cd2+ and Pb2+ respectively, at a deposition time of 120 seconds. The NG-PG-BiE showed similar detection limits of 0.167 μg L-1, 0.098 μg L-1 and 0.125 μg L-1 for Zn2+, Cd2+ and Pb2+ respectively. For real sample analysis, the enhanced voltammetric sensor proved to be suitable for the detection and quantitation of heavy metals below the US EPA prescribed drinking water standards of 5 mg L-1, 5 μg L-1 and 15 μg L-1 for Zn2+, Cd2+ and Pb2+ respectively.en_US
dc.language.isoenen_US
dc.publisherUniversity of the Western Capeen_US
dc.subjectHeavy metal detectionen_US
dc.subjectGrapheneen_US
dc.subjectBismuth-filmen_US
dc.subjectTrace metal analysisen_US
dc.titleGraphene-modified pencil graphite bismuth-film electrodes for the determination of heavy metals in water samples using anodic stripping voltammetryen_US
dc.rights.holderUniversity of the Western Capeen_US


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