Thesis (PhD)--University of South Australia, 1995

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [188]-197).

Flow injection analysis offers distinct advantages in reproducibility, flexibility, sample throughput and cost performance. Since it was introduced in 1975, there are more than 10 000 publications to date. The present study focuses on the development of process analysers for the determination of nitrogen compounds (namely, nitrate, nitrite and protein), nickel, and phosphate in various combination in samples originating from various fields, such as foodstuffs, water, and fertilisers. Nitrite is potentially unstable; it decomposes with time under acidic medium with an increase in decomposition rate as the concentration of acid increases. Raman spectroscopy was employed as a means of determining the rate of decomposition of nitrite in solutions at various pH values. A simple method for the determination of nitrite in foodstuffs by flow injection analysis (FIA) is described. The foodstuffs containing nitrite are digested in a microwave oven and then treated with 1 moℓ/Q NH4CI solution at pH 9. The simultaneous determination of nitrate and nitrite in foodstuffs and water was also studied. Cadmium (coarse powder) was used to reduce nitrate to nitrite. The effect of pH, length of reductor column, and various types of cadmium reductor on the yield of nitrite are investigated. The flow injection method was developed for the spectrophotometric determination of nickel in cured meat. Dimethylglyoxime (DMG) in acetate buffer at pH 6.4 nickel forms a red complex which is measured at 475 nm. The effects of chemical and physical parameters in flow injection analysis were studied. A new bienzymatic amperometric sensor is proposed for the assay of proteins in milk. The sensor is based on two enzymes, namely, carboxypeptidases A and L-amino acid oxidase. The use of flow injection analysis and Raman spectroscopy for the determination of phosphate in foodstuffs and fertilisers, is also compared in this study. / Thesis (PhD (Chemistry))--University of Pretoria, 2007. / Chemistry / unrestricted

Quartz crystal microbalances, (QCM), are high frequency oscillators, capable of nanogram mass resolution in both air and liquid environments. ~ work has produced data showing the feasibility of using the QCM for monitoring interactions in liquids for several types of systems and has allowed comparison with surface plasmon resonance (SPR) where appropriate. Bulk phase changes in viscosity and density have been used in the development of a QCM agglutination assay for the Staphylococcus epidermidis infection which has reduced diagnosis periods by a factor of twelve. Direct interactions at the crystal electrode have been employed when studying bacterial adhesion to protein treated gold surfaces. It was shown that suspensions containing as little as I x 10-2 cellsml-1 could be recognised using the QCM system. A novel boronic acid - vicinal diol interaction mechanism has been employed as a model for receptor-ligand binding. New boronic acid disulphide and short chain thiol derivatives have been synthesised and the formation of self assembled monolayers of the~e compounds monitored, both on the gold QCM electrodes and on the gold films of SPR slides, the assembly mechanism being shown to fit a two stage model shown by other workers for straight chain thiols. Monolayer orientation was confirmed using SPR, by the binding of a range of saccharides and the diol containing enzyme cofactor nicotinamide adenine dinucleotide. The enzymes lactate dehydrogenase and glucose-6-phosphate dehydrogenase have been shown to interact with bound NAD using both a novel flow injection system with QCM detection and SPR. The low molecular weight saccharide, glucose, was shown to bind reversibly to GDH on the surface of a QCM and the potential for kinetic stu4ies recognised. This was taken one step further with a preliminary investigation into sensing within real fluids, using diluted and spiked human seruin samples.

No description available.

by Kwan Hok-wing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 67-69). / Abstracts in English and Chinese. / Acknowledgment --- p.i / Abstract --- p.ii / Chapter 1. --- INTRODUCTION / Chapter 1.1 --- Chemical speciation of cyanide --- p.1 / Chapter 1.2 --- Review of analytical techniques for cyanide determination --- p.3 / Chapter 1.3 --- Importance of sediment in the environment --- p.6 / Chapter 1.4 --- Characteristics of marine sediment --- p.6 / Chapter 1.5 --- Antropogenic sources of cyanide --- p.7 / Chapter 1.6 --- Research objective --- p.8 / Chapter 1.7 --- Brief description of the project --- p.9 / Chapter 2. --- INSTRUMENTATION AND THEORY / Chapter 2.1 --- Instrumentation for flow injection analysis system --- p.11 / Chapter 2.2 --- Basic principles of flow injection analysis --- p.21 / Chapter 2.3 --- Basic principles of amperometric detection --- p.24 / Chapter 3. --- EXPERIMENTAL / Chapter 3.1 --- Instrumentation --- p.25 / Chapter 3.2 --- Reagents --- p.32 / Chapter 3.3 --- Sample preparation --- p.34 / Chapter 4. --- RESULTS AND DISCUSSION / Chapter 4.1 --- Effect of bismuth on on-line precipitation of sulphide in FIA --- p.37 / Chapter 4.2 --- Calibration --- p.37 / Chapter 4.3 --- Effectiveness of the distillation conditions --- p.41 / Chapter 4.4 --- Comparisons of cyanide extraction methods for sediment analysis --- p.42 / Chapter 4.5 --- Effect of bismuth nitrate on cyanide recoveries --- p.45 / Chapter 4.6 --- Effect of bismuth nitrate on cyanide recoveries in the presence of sulphide --- p.48 / Chapter 4.7 --- Effect of bismuth nitrate on recoveries of total cyanide in the analysis of interlaboratory test samples --- p.55 / Chapter 4.8 --- Recoveries of complexed cyanide in the analysis of SETOC sample with sulphide interference --- p.57 / Chapter 4.9 --- Analysis of marine sediment samples --- p.58 / Chapter 4.10 --- Recovery tests and precision studies --- p.59 / Chapter 4.11 --- Interferences --- p.62 / Chapter 5. --- CONCLUSION --- p.66 / Chapter 6. --- REFERENCES --- p.67

Amperometric dectection of heparin and glucosamine in flow injection analysis

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 145-148).

No description available.

Thesis (PhD) -- University of South Australia, 1993