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Durham e-Theses
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Characterisation of luminescent and electrochemical sensors.

Blair, Stephanie (2001) Characterisation of luminescent and electrochemical sensors. Doctoral thesis, Durham University.



This thesis is concerned with electrochemical and optical sensors based on potentiometric and luminescent transduction. A series of oxa-diisobutylamide derivatives based on cis-cis-l,3,5-cyclo-hexanetriol was compared in standard polyvinyl chloride based ion-selective electrodes as ionophores for the detection of selected IA/IIA cations. The tripodal framework incorporated either mono-, di- or tri- substituted diisobutyl amide pendant groups to give possible coordination numbers of 4, 5 and 6 respectively, assuming a 1:1 cationionophore stoichiometry. A Nemstian response towards the detection of Ca(^2+) was observed with the ISE incorporating the di-substituted diamide analogue. The selectivity of the ISE was assessed using the Fixed Interference Method and a Nemstian response was observed in the extracellular Ca(^2+) concentration range (1.16-1.32 mmol dm(^-3)) in the presence of a simulated extracellular background of interfering cations. The effect of pH on the response of the ISE was also investigated as was the enhancement of the lower detection limit by including a Ca(^2+) buffer in the inner filling electrolyte. Luminescent lanthanide complexes were assessed as chemical transducers for the purpose of optical sensing of pH or dissolved oxygen, following immobilisation in sol- gel thin films prepared in acidic media. pH-dependent intensity or ratiometric methods were defined for europium and terbium complexes of cyclen based frameworks (12-N(_4)). These systems incorporated phenanthridine derivatives or para substituted aryl sulfonamide moieties as the sensitising chromophores, typically with apparent pH sensing ranges of 5.5 to 8.0.Dissolved oxygen-dependent modulation of the metal emission and excited state lifetime of a short series of terbium complexes was assessed. These systems were based on cyclen with either tetra-amide or mono-amide triphosphinate pendent groups.

Item Type:Thesis (Doctoral)
Award:Doctor of Philosophy
Thesis Date:2001
Copyright:Copyright of this thesis is held by the author
Deposited On:01 Aug 2012 11:41

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