Thesis (Ph. D.)--Pennsylvania State University, 1968. / Includes bibliographical references.

Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: Abraham M. Lenhoff, Dept. of Chemical Engineering. Includes bibliographical references.

A new general method is developed for the optimization of HPLC ternary or pseudo-quaternary mobile phases which are represented by the trilinear coordinate system. This method can predict the global optimum of the mobile phase composition. The global optimum composition along each edge of the triangle and the corresponding selectivity factor of the worst-separated peak pair(s) are used in this method. This method is named the weighted pattern comparison optimization method (WPCO) and is applicable for both known and unknown samples. The WPCO method is simpler than those currently in use. The WPCO method was tested by using 68 literature data sets whose separation response surfaces are different. Results of the WPCO method agree with the results obtained by the minimum α plot method and by the grid search method, and do so with substantially fewer experimental measurements. Compared with the 5% (in eluent composition) step size grid-search procedure, the WPCO method using the same step size reduces the experimental work by 75%. For further reducing the experimental work, the original WPCO method is simplified. In an ordinary HPLC separation, the separation factor and resolution are approximately proportional to the logarithm of the selectivity factor. Based on this, the separation factor replaces the logarithm of selectivity factor in the original WPCO method. This further reduces the experimental work and avoids the error introduced in the measurement of the column dead volume. The simplified WPCO method has been tested in the normal-phase and reversed-phase chromatography separation cases. The simplified WPCO method has been tested by using 27 literature data sets whose separation response surfaces are different. Results of the simplified and original WPCO methods are nearly identical when the capacity factors of the solutes of the worst-separated peak pairs are greater than 5. When the capacity factors are less than 5, the simplified WPCO method is satisfactory in less complex, less critical applications. Two new metabolites of nefopam have been separated from greyhound urine. In the separation process, flash chromatography is used for cleaning up and preseparating the samples in a single step. Compared with other techniques, experimental work is reduced. The structure of one of the newly discovered metabolites is determined using MS and NMR. The most probable structure of the other metabolite is determined using MS. The main metabolic pathways at different doses in greyhounds are studied. / Graduation date: 1991

A study was made of subspeciation in Asclepias tuberosa using descending paper chromatography. An attempt was made to characterize the three subspecies of Asclepias tuberosa on the basis of amino acid and phenolic patterns.The amino acid patterns were of little value for differentiating the subspecies.The fluorescent phenolic compounds of Asclepias tuberosa were analyzed by placing the chromatograms under longwave ultraviolet light and under longwave ultraviolet light in the presence of ammonia vapor.The patterns of the three subspecies produced under ultraviolet light and under ultraviolet light in the presence of ammomia vapor showed identifying markers for each of the three subspecies. Hybrid plants were also distinguished.Ball State UniversityMuncie, IN 47306

AbstractA study was made to determine if the age of a herbarium specimen of Equisetum hiemale had any effect on the chromatographic patterns. Specimens of E. hiemale were analyzed employing descending paper chromatography and electrophoresis.The amino acid and phenolic patterns were of significant value in determining if the chromatographic patterns varied as the herbarium specimen aged. The fluorescent phenolic compounds of E. hiemale were analyzed by placing the chromatograms under long wave ultraviolet light. The free amino acids were detected by spraying the chromatogram. with ninhydrin.The chromatographic patterns showed that the age of the oldest herbarium specimen investigated had no effect on its patterns.Ball State UniversityMuncie, IN 47306

No description available.

No description available.

Thesis (Ph. D.)--Florida State University, 2004. / Advisor: Dr. John G. Dorsey, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed June 16, 2004). Includes bibliographical references.

La determinació de 2,4,6-tricloroanisole (TCA) i altres cloroanisoles en vins i taps de suro és de vital importància, tant en la industria enològica com en al surera, pel control d’un dels defectes organolèptics del vi que ha causat més prejudicis: l’olor a humitat, clàssicament conegut com a gust a suro. En aquesta tesi doctoral s’han desenvolupat i validat aquestes metodologies, tot aplicant la microextracció en fase sòlida i la cromatografia de gasos, ja sigui en detecció de captura electrònica com d’espectrometria de masses, per tal de donar respostes al sector empresarial per dur a terme aquest control. A més, la definició i determinació del TCA total en el suro, en contraposició al TCA extraïble, més habitual en la indústria surera, s’ha presentat en aquest treball com una opció més objectiva en el control de qualitat, oferint una bona eina per tal d’evitar l’aparició de “l’olor a humitat” en els vins. / The determination of 2,4,6-trichloroanisole (TCA) and other chloroanisoles in wines and cork stoppers is of great importance, in both wine and cork industry, as a quality control of one of the organoleptic defects that is causing more economical losses: The humidity odor, traditionally known as cork taint. In this doctoral thesis different analysis methods has been developed, applying the solid phase microextraction and the gas chromatography, coupled either with mass spectrometry of electron capture detection, to give solutions to the industry as a quality control. In this work has been introduced the concept “Total TCA”, in contraposition to the “Releasable TCA”, frequently used in the cork industry. The “TCA total” is presented as a more objective parameter of quality control, giving a very good tool to control de “humidity odor” and avoid its presence in wine.

No abstract available. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1996.