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Title: The liquid/liquid interface as a transducer for chemical sensor design
Author: Osborne, Murray
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1993
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This thesis is devoted to the development of the interface between two immiscible electrolyte solutions as a transducer for chemical sensor design. The main detectable analyte of interest is the ammonium ion. The facilitated ion transfer of this species is reported using a variety of ionophores. Association constants of the ammonium ion with dibenzo-18-crown-6, nonactin and valinomycin are calculated along with values for the same ionophores with potassium and sodium ions. The selectivity towards these three species is such as not to enable their separation at physiological levels. A single microhole formed by excimer laser photoablation in a polyester film is used as a support for a micro liquid/liquid interface. The effect of a decrease in the supporting electrolyte concentrations of both the organic and aqueous phases is investigated with regard to ion and facilitated ion transfer reactions. It is shown that it is possible to study ion transfer reactions using simply pure water as the aqueous phase electrolyte. The ITIES is used as a transducer to follow enzymatic reactions. The ammonium ion produced in the urea/urease and creatinine/creatinine deiminase enzymatic decompositions is detected by facilitated ion transfer using dibenzo-18-crown-6. The adsorption/transfer of the polyelectrolyte Nafion at the ITIES is investigated. The two characteristic transfer phenomena observed are attributed to the adsorption/transfer of Nafion in its dissolved form and a restructured form of the polyelectrolyte. A biosensor for urea is proposed where the ITIES has been 'solidified' in the form of polymeric films.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available