Development of electrochemical sensors containing bimerallic silver and gold nanoparticles

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dc.contributor.advisorIwuoha, Emmanuel
dc.contributor.advisorBaker, Priscilla G.L.
dc.contributor.authorMailu, Stephen Nzioki
dc.contributor.otherDept. of Chemistry
dc.contributor.otherFaculty of Science
dc.date.accessioned2014-01-15T06:55:36Z
dc.date.accessioned2024-05-09T10:50:09Z
dc.date.available2011/05/16 10:34
dc.date.available2011/05/16
dc.date.available2014-01-15T06:55:36Z
dc.date.available2024-05-09T10:50:09Z
dc.date.issued2010
dc.descriptionMagister Scientiae - MScen_US
dc.description.abstractPolyaromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants that have been shown to be teratogenic, mutagenic and carcinogenic and pose serious threats to the health of aquatic and human life. Several methods have been developed for their determination such as immunoassay, gas chromatography and high performance liquid chromatography (HPLC) in combination with fluorescence or absorbance detection. However, these methods are known to manifest underlying disadvantages such as complicated pretreatment, high costs and time consuming processes. In this work, a simple, less time consuming electrochemical method in the form of an electrochemical sensor has been developed for the detection of PAHs. The sensor was fabricated by the deposition of silver-gold (1:3) alloy nanoparticles (Ag-AuNPs) on ultrathin overoxidized polypyrrole (PPyox) film which formed a PPyox/Ag-AuNPs composite on glassy carbon electrode (PPyox/Ag-AuNPs/GCE). The silver-gold alloy nanoparticles deposited to form the composite were chemically prepared by simultaneous reduction of silver nitrate (AgNO3) and chloroauric acid (HAuCl4) using sodium citrate and characterized by UV-visible spectroscopy technique which confirmed the homogeneous formation of the alloy nanoparticles. Transmission electron microscopy showed that the synthesized nanoparticles were in the range of 20-50 nm. The properties of the composite formed upon deposition of the nanoparticles on the PPyox film were investigated by electrochemical methods. The PPyox/Ag-AuNPs/GCE sensor showed strong catalytic activity towards the oxidation of anthracene, phenanthrene and pyrene, and was able to simultaneously detect anthracene and phenanthrene in a binary mixture of the two. The catalytic peak currents obtained from square wave voltammetry increased linearly with anthracene, phenanthrene and pyrene concentrations in the range of 3.0 x 10-6 to 3.56 x 10-4 M,3.3 x 10-5 to 2.83 x 10-4 M, 3.3 x 10-5 to 1.66 x 10-4 M and with detection limits of 0.169 μM, 1.59 μM and 2.70 μM, respectively. The PPyox/Ag-AuNPs/GCE sensor is simple, has antifouling properties and is less time consuming with a response time of 4 s.en_US
dc.description.countrySouth Africa
dc.identifier.urihttps://hdl.handle.net/10566/14486
dc.language.isoenen_US
dc.publisherUniversity of the Western Capeen_US
dc.rights.holderUniversity of the Western Capeen_US
dc.subjectPolyaromatic hydrocarbons (PAHs)en_US
dc.subjectElectrochemical sensoren_US
dc.subjectOveroxidized-polypyrrole composite (PPyox)en_US
dc.subjectSilver-gold bimetallic alloy nanoparticles (Ag-AuNPs)en_US
dc.subjectPolypyrrole polymer (PPy)en_US
dc.subjectAnthracene (AN)en_US
dc.subjectPyrene (Py)en_US
dc.subjectPhenanthrene (PHE)en_US
dc.subjectCyclic voltammetry (CV)en_US
dc.subjectSquare wave voltammetry (SWV)en_US
dc.subjectElectrochemical impedance spectroscopy (EIS)en_US
dc.subjectBimetallic nanoparticlesen_US
dc.titleDevelopment of electrochemical sensors containing bimerallic silver and gold nanoparticlesen_US
dc.typeThesisen_US

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