No description available.

Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / The recent discovery of a number of metabolites of estrogens has necessitated the development of new methods for their analysis. The available methods of proven merit fall short of determining these newer fractions. Moreover, these methods are too time consuming to determine the daily excretion of estrogenic steroids. The development of a relatively rapid and highly sensitive methodfor the estimation of several estrogens was, therefore, undertaken. The procedure involves hydrolysis, extraction, preliminary purification and separation, acetylation and gas chromatography of the steroids. Simultaneous separation and quantification by gas-liquid chromatography (GLC) not only allows a more rapid analysis but sensitivity is also increased by the use of ionization detectors. Determination of the optimal flow rate of hydrogen, air and carrier gas was found necessary for obtaining maximum detection response. Detector linearity for seven estrogens over an adequate range was established. Since free estrogens suffer severe adsorption on the gas chromatographic column and generally do not separate well, the steroids were analyzed as suitable derivatives. After examining several such derivatives (acetates, formate, trifluoroacetate, trimethylsilyl ethers) the acetates were found to be most suitable for the specific purpose. Optimal conditions for the acetylation of steroids in submicrogram quantities were established. The effect of the solid support, stationary phase, priming of the column with estrogens and solvent impurity in quantitative analysis by gas chromatography was also investigated. Preliminary separation of estrogens into separate groups was necessary because of poor resolution and long retention times resulting in poor detector response. Moreover, in a crude urine extract, the large number of contaminants obscuring the peaks of the lesser estrogen components, mandated preliminary purification. Thin-layer chromatography crtc) was found to be a versatile tool for this purpose. Among several solvent systems developed, three were found to be eminently suitable. TLC in System I (benzene:ethyl acetate 1:1) separates the estrogens into four fractions: (a) estrone and 2-methoxyestrone, (b) ring-D-alpha-ketols and estradiol, (c) 16-epiestriol, and (d) estriol. Further TLC of fraction (b) in System II (pet. ether:dichloromethane:ethanol 10:9:1) was found necessary to separate these estrogens from the neutral 17-ketosteroid. An alternate method of preliminary purification and separation for the measurement of the three classical estrogens in low titer urine, involving alumina chromatography, has been developed. Following these preliminary procedures GLC permitted rapid separation and highly sensitive quantification of the individual fractions [TRUNCATED] / 2999-01-01

Call number: LD2668 .T4 1964 M26 / Master of Science

No description available.

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.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 140-153). Available also in a digital version from Dissertation Abstracts.

Graduation date: 1962

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 34-36).