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Development of amperometric biosensor with cyclopentadienylruthenium (II) thiolato schiff base self-assembled monolayer (SAM) on gold

Magister Scientiae - MSc / A novel cyclopentadienylruthenium(II) thiolato Schiff base, [Ru(SC6H4NC(H)C6H4OCH2CH2SMe)(η5-C2H5]2 was synthesized and deposited as a selfassembled monolayer (SAM) on a gold electrode. Effective electronic communication between the Ru(II) centers and the gold electrode was established by electrostatically cycling the Shiff base-doped gold electrode in 0.1 M NaOH from -200 mV to +600 mV. The SAMmodified gold electrode (Au/SAM) exhibited quasi-reversible electrochemistry. The integrity of this electro-catalytic SAM, with respect to its ability to block and electro-catalyze certain Faradaic processes, was interrogated using Cyclic and Osteryoung Square Wave voltammetric experiments. The formal potential, E0', varied with pH to give a slope of about - 34 mV pH-1. The surface concentration, Γ, of the ruthenium redox centers was found to be 1.591 x 10-11 mol cm-2. By electrostatically doping the Au/SAM/Horseradish peroxidase at an applied potential of +700 mV vs Ag/AgCl, a biosensor was produced for the amperometric analysis of hydrogen peroxide, cumene hydroperoxide and tert-butylhydroperoxide. The electrocatalytic-type biosensors displayed typical Michaelis-Menten kinetics with their limits of detection of 6.45 M, 6.92 M and 7.01 M for hydrogen peroxide, cumene hydroperoxide and tert-butylhydroperoxide respectively. / South Africa

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uwc/oai:etd.uwc.ac.za:11394/2391
Date January 2007
CreatorsTicha, Lawrence Awa
ContributorsBaker, Priscilla, Iwuoha, Emmanuel, Dept. of Chemistry, Faculty of Science
PublisherUniversity of the Western Cape
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeThesis
RightsUniversity of the Western Cape

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