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Fabrication and use of new solid state phosphate ion selective electrodes for monitoring phosphorylation and dephosphorylation reactions

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dc.contributor.advisor Tafesse, Fikru
dc.contributor.author Enemchukwu, Emeka Martin
dc.date.accessioned 2013-10-28T12:18:37Z
dc.date.available 2013-10-28T12:18:37Z
dc.date.issued 2012-06
dc.identifier.citation Enemchukwu, Emeka Martin (2012) Fabrication and use of new solid state phosphate ion selective electrodes for monitoring phosphorylation and dephosphorylation reactions, University of South Africa, Pretoria, <http://hdl.handle.net/10500/11955> en
dc.identifier.uri http://hdl.handle.net/10500/11955
dc.description.abstract Highly selective and sensitive phosphate sensors have been fabricated by constructing a solid membrane disk consisting of variable mixtures of aluminium powder (Al), aluminium phosphate (AlPO4) and powdered copper (Cu). Both binary and ternary electrode systems are produced depending on their composition. The ternary membranes exhibit greater selectivity over a wide range of concentrations. The ternary electrode with the composition 25% AlPO4, 25% Cu and 50% Al was selected as our preferred electrode. The newly fabricated ternary membrane phosphate selective electrodes exhibited linear potential response in the concentration range of 1.0 × 10−6 to 1.0 × 10−1 mol L−1. The electrodes also exhibit a fast response time of <60 s. Their detection limit is 1.0 × 10−6 mol L−1. The unique feature of the described electrodes is their ability to maintain a steady and reproducible response in the absence of an ionic strength control. The electrodes have a long lifetime and can be stored in air when not in use. The selectivity of the new phosphate selective electrodes with respect to other common ions is excellent. The results obtained provide further insight into the working principles of the newly fabricated phosphate selective electrodes. Dephosphorylation and phosphorylation reactions were monitored using the preferred phosphate selective electrode. The following reactions were studied and inferences drawn; (a) the reactions between *[{CoN4(OH)(OH2)}]2+ and *[OH(PO2O)]2- for 1:1, 2:1 and 3:1 *[{CoN4(OH)(OH2)}]2+ to *[OH(PO2O)]2- ratios.(b) the reactions between *[{CoN4(OH)(OH2)}]2+ and *[O2NC6H4PO2(O)(OH)]- for 1:1, 2:1 and 3:1 *[{CoN4(OH)(OH2)}]2+ to *[O2NC6H4PO2(O)(OH)]- ratios. (c) the reactions between *[{CoN4(OH)(OH2)}]2+ and *[(OH)2(PO2)2O]2- for 1:1, 2:1 and 3:1 [{CoN4(OH)(OH2)}]2+ to *[(OH)2(PO2)2O]2- ratios, and (d) the reactions between *[{CoN4(OH)(OH2)}]2+ and *[(OH)2(PO2)3O2]3- for the 1:1, 2:1 and 3:1 [{CoN4(OH)(OH2)}]2+ to *[(OH)2(PO2)3O2]3- ratios. Further insight into dephosphorylation and phosphorylation reactions is unravelled by the novel phosphate selective electrode monitoring. *For clarity of the complexes utilized, see chapter 4, table 4.1. KEY WORDS; Dephosphorylation, phosphorylation, ion selective electrodes, phosphate ion selective electrode, decontamination, electromotive force, potential difference, activity, concentration, selectivity coefficient, calibration, ionic strength, hydrolysis, inorganic phosphates, nitrophenylphosphate, pyrophosphate, tripolyphosphate, organophosphate esters. en
dc.format.extent 1 online resource (xx, 175 p.)
dc.language.iso en en
dc.subject Dephosphorylation
dc.subject Phosphorylation
dc.subject Ion selective electrodes
dc.subject Phosphate ion selective electrode
dc.subject Decontamination
dc.subject Electromotive force
dc.subject Potential difference
dc.subject Selectivity coefficient
dc.subject Calibration
dc.subject Ionic strength
dc.subject Hydrolysis
dc.subject Inorganic phosphates
dc.subject Nitrophenylphosphate
dc.subject Pyrophosphate
dc.subject Tripolyphosphate
dc.subject Organophosphate esters
dc.subject.ddc 541.39
dc.subject.lcsh Phosphate esters
dc.subject.lcsh Electrodes, Ion selective
dc.subject.lcsh Calibration
dc.subject.lcsh Phosphates
dc.subject.lcsh Solid state chemistry
dc.title Fabrication and use of new solid state phosphate ion selective electrodes for monitoring phosphorylation and dephosphorylation reactions en
dc.type Thesis en
dc.description.department Chemistry en
dc.description.degree D.Phil (Chemistry)


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