Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 68-73). Also available via the Internet.

The distribution of hydrophobic ionogenic organic compounds (HIOC's) between aqueous and nonaqueous phases has been investigated. The HIOC's are aniline and methyl substituted anilines. The aqueous phases are methanol-water mixed solvents with varying pH and ionic strength. The nonaqueous phases are silica and alkyl derivatized silica with ethyl- (C-2), octyl- (C-8), and octadecyl- (C-18) silanes. A gas-liquid equilibration method has been developed to determine the Henry's law constants and the activity coefficients of methyl anilines in methanol-water mixed solvents. The logarithm of the Henry's law constants vary quadratically with the volume fraction of methanol. The chromatographic study has been performed to investigate the effect of three mobile phase factors, fraction of methanol, pH, and ionic strength, on the retention of methyl anilines on different stationary phases. The logarithm of mass distribution ratios, log k's, of methyl anilines vary linearly with the volume fraction of methanol. The ratios of H / k' of methyl anilines increase with increase in methanol in the mobile phase, indicating an increase in the activity coefficients in the stationary phases. This observation is found to be true for different methyl anilines in different stationary phases. A partition model is presented to describe the effect of pH and ionic strength on the retention of HIOC's in the mobile phase. The variation in log k' among neutral and ionic methyl anilines can be explained by linear free energy relationships. Equations are established to predict retention of neutral or ionized methyl anilines from their octanol-water partition coefficients at any methanol content in the mobile phase. Acid dissociation constants of methyl anilines determined from the dependence of log k' on pH are in close agrement with those determined by potentiometric titrations. The effect of ionic strength on the retention of both neutral and ionic species of methyl anilines is negligible. That is, the contribution from electrostatic energy and salting out effect are not significant. The chromatographic study is extended to study the retention of methyl anilines on silica as a function of pH and methanol at a constant ionic strength. The dependence of retention on pH is qualitatively interpreted from an ion exchange reaction between the dissociated silanol groups in the surface and the ionized methyl anilines. The effect of methanol on the retention of methyl anilines and of pyridine on silica is described by a quadratic relationship between the log k' and volume fraction of methanol. / Graduation date: 1990

No description available.

Thesis (Ph.D.)--University of Wyoming, 2008. / Title from PDF title page (viewed on August, 3 2009). Includes bibliographical references (p. 131-139).

A metabolite of a widely used pesticide, paraoxon, exerted a dramatic mutagenic synergistic effect in Salmonella typhimurium with a number of mammalian-activated or plant-activated aromatic amines and heterocyclic amines. The mutagenic synergy required an activated an aromatic amine, and was not attributable to the generation of new mutagenic products or to the modification of the stability of the activated aromatic amine products. Paraoxon modulated the genotoxic potency of dietaiy heterocyclic amines in human cells. The results of this study raise the concern of the environmental effects of organophosphorus ester insecticides. A clone of the Chinese hamster ovary cell line, AS52, was isolated, characterised and analysed under identical treatment conditions with the mutagens 2-acetoxy-acetylaminofluorene (2AAAF), ethyl methanesulphonate (EMS), and UV radiation. The genetic endpoints included acute DNA damage detected in the alkaline single cell gel electrophoresis (SCGE) assay, whole cell clastogenicity detected with laser beam flow cytometry and forward mutation at a target gene. There were statistically significant increases in DNA damage and forward mutation with all three mutagens. Statistically significant increases in chromosome damage were observed with 2AAAF and EMS but not with UV. A non-uniform distribution of DNA damage throughout the genome was indicated with the chemical mutagens in the SCGE assay. Another type of modulation in genotoxic response was investigated whereby numerous commercial soybean processing products and by-products were analysed for their antimutagenic and antigenotoxic activities. Antimutagenic activity was detected in a soybean processing by-product, soybean molasses and in an ethanol extract, fraction PCC. PCC protected mammalian cells against direct DNA damage, clastogenic damage and point mutation induced by 2AAAF. A fraction of PCC, PCC100 was an effective antimutagen in mammalian cells and in human lymphocytes. Analytical chemical studies identified the compounds responsible for the antimutagenic activity as the soyasaponins I, III and V.

No description available.

Thesis (doctoral)--Lund University, 1994.

Thesis (doctoral)--Lund University, 1994.

Thesis (Ph. D.)--University of Missouri--Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 113-122). Also available on the Internet.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [134]-149).