No description available.

The primary purpose of this study was to continue the search for a suitable liquid phase which could be utilized in a gas chromatographic study of actinomycetic tastes and odors. Of equal importance were the attempts to characterize the compounds found in the odor water.

To assess the significance of pollutants released into the environment it is necessary to determine both the extent of contamination and the biological effects they give rise to. This research is based on a tiered system, which commences with conventional analytical chemistry (gas chromatography), followed by the development, evaluation and application of rapid and simple immunochemical techniques and, finally, the integration of chemical and biological markers to assess pollution. GC-ECD/FID/MS have been used to investigate the status of chemical contamination of the Black Sea by organochlorine residues, hydrocarbons and faecal sterols. Useful information is provided and problems with e.g. HCHs and sewage contamination are highlighted. Contamination by DDTs, PCBs, "total" hydrocarbons and PAHs is also reported. Next, these techniques are used to develop rapid screening methods. Four distinct applications of immunochemical techniques are presented. Initially, the BTEX RaPDD Assay® ELISA is evaluated to detect semi-volatile hydrocarbons in contaminated groundwater. Although overestimating concentrations when compared to GC-FID/PID, results are well correlated. Secondly, the effectiveness o f the BTEX and c-PAH RaPID Assay® to detect hydrocarbons in sediments is tested. Once again, good agreement with GC-FID/MS confirms the ELISA to be a useful screening protocol to focus more expensive high-resolution analytical techniques. The adaptability and applicability of an ELISA (PCB RaPID Assay®) method in measuring "total" PCB levels in mussel tissue is demonstrated. An underestimation of concentrations, despite of covariability between ELISA and cGC-ECD, is discussed. Next, ELISA (RaPID Assay®) and fluorometry were successfully applied to quantify PAH metabolites in crab urine as a measure of exposure. HPLC analyses indicated that conjugate PAH metabolites were dominant in urine of crabs exposed to pyrene. Differences could also be identified between crabs taken from clean and contaminated sites. Finally, an integration of chemical and biological techniques is used to investigate contamination and effects in mussels within a pollution gradient. Results indicate a correlation between micronucleus formation, heart rate and PCB and PAH level.

Call number: LD2668 .T4 1959 P65

by Wu Siu Yu Portia. / Bibliography: leaves 105-107 / Thesis (M.Ph.)--Chinese University of Hong Kong

by Leung Yun-to, Ada. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 114-115). / Acknowledgment --- p.i / Abstract --- p.ii / Chapter 1. --- INTRODUCTION / Chapter 1.1 --- Review of gas-liquid chromatographic and other chromatographic techniques --- p.1 / Chapter 1.2 --- "Structures, actions and uses of the drugs under study" --- p.5 / Chapter 1.3 --- Research objectives --- p.10 / Chapter 2. --- INSTRUMENTATION AND THEORY / Chapter 2.1 --- Instrumentation for gas chromatography --- p.11 / Chapter 2.2 --- Basic principles in chromatography --- p.23 / Chapter 3. --- EXPERIMENTAL / Chapter 3.1 --- Instrumentation --- p.27 / Chapter 3.2 --- "The counter-check GC method for camphor, menthol and methyl salicylate" --- p.29 / Chapter 3.3 --- The counter-check HPLC method for thymol --- p.29 / Chapter 3.4 --- The counter-check HPLC method for phenol --- p.30 / Chapter 3.5 --- The counter-check HPLC method for benzoic acid --- p.31 / Chapter 3.6 --- The counter-check HPLC method for salicylic acid --- p.32 / Chapter 3.7 --- Reagents --- p.33 / Chapter 3.8 --- Sample preparation --- p.34 / Chapter 3.9 --- "Quantitative determination of benzoic acid, camphor, menthol, methyl salicylate, phenol, salicylic acid and thymol in various pharmaceutical preparations" --- p.35 / Chapter 4. --- RESULTS AND DISCUSSION / Chapter 4.1 --- Choice of column --- p.36 / Chapter 4.2 --- Optimization of chromatographic conditions --- p.44 / Chapter 4.3 --- Choice of solvent --- p.51 / Chapter 4.4 --- Calibration --- p.59 / Chapter 4.5 --- Reproducibility of the GC measurements --- p.95 / Chapter 4.6 --- Recovery test and precision studies --- p.96 / Chapter 4.7 --- Simultaneous determination of the drugs under study in various pharmaceutical preparations --- p.100 / Chapter 5. --- CONCLUSION --- p.113 / Chapter 6. --- REFERENCES --- p.114

No description available.

The three factors of the resolution (Rs)equation(see Equation 1.1)were explored in this thesis. During the course of the research project, an important aim was to explore separation processes that would lead to an increase in productivity without sacrificing Rs. To that end, an increase in the retention factor (k)to enhance Rs was deemed detrimental to the cycle time, hence the production rate, particularly when preparative separations are involved. Consequently the primary objectives were to (i)prepare more efficient columns and (ii)investigate new strategies in manipulating selectivity. The significance of the work contained in this thesis is highlighted in 27th International Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC 2003)held in Nice, France between 15-19 June, 2003. Many of the papers presented significantly compared to chapters contained in this research / Doctor of Philosophy (PhD)

This thesis describes a developmental process required for the construction and optimisation of two-dimensional liquid chromatographic systems. The text encompasses much of the difficulties and provides a frame work for achieving positive results. The hardware requirements and the concepts for successful completion of heart-cutting and comprehensive modes of separation are addressed. Low molecular weight polystyrenes play an essential role in providing a model framework or theme for the development of two-dimensional liquid chromatographic systems. Low-molecular weight oligostyrenes were initially used to provide a theoretical assessment of combinations of liquid chromatographic systems. Interpretation of theoretical results then allowed for the development of a heart-cutting two-dimensional liquid chromatographic system for the separation of oligostyrene complex samples. This allowed for practice to be compared with the theoretical results, which are presented and provided direction as to what attributes of a two-dimensional liquid chromatographic system are beneficial. Petroleum oils are one of the most complex mixtures found in the natural environment and are included to provide a real-world application that demonstrates the potential power of comprehensive two-dimensional liquid chromatographic systems. Orthogonality is a central theme throughout the whole thesis. Separation correlation is shown to be advantageous in certain instances in the evaluation of hybrid stationary phases, as shown in the analysis of a low molecular weight polystyrene sample. The thesis finishes by the incorporation of monolithic separation media as an alternative second dimension stationary phase support. A method is discussed that allows for a substantial increase in the volume and concentration loading of two-dimensional liquid chromatographic systems that employ monolithic chromatography columns in the second dimension. This is important since volume overloading and concentration overloading in the second dimension can reduce separation performance and hence the final chapter provides a new direction for research. / Doctor of Philosophy (PhD)

Thesis (M. Sc. (Chemistry) -- University of Pretoria. 2006. / Includes bibliographical references (leaves 111-117).