Submitted in partial fulfillment of the requirements for the degree of Masters in Technology in Chemistry, M.L. Sultan Technikon, 2000. / Mycotoxins are a group of natural poisons produced by certain strains of fungal species when they grow under favourable conditions on a wide variety of different substrates. These toxins have been implicated in a wide range of acute diseases in man and animals. Their toxic effects include oesophageal cancer and liver diseases in humans, and carcinogenic effects in experimental rats and poultry. Hence, there is a need to monitor toxin levels in food commodities. / M

Made available in DSpace on 2014-10-09T12:36:24Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:27Z (GMT). No. of bitstreams: 1 03870.pdf: 1902018 bytes, checksum: b71668a19608bf1dfac9fe0ccc14974b (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

No description available.

Human chorionic gonadotropin (HCG), a glycoprotein hormone with two nonidentical subunits, is produced by chorionic tissue in pregnant women and by neoplastic tissue containing chorionic elements. It is used in the treatment of male hypogonadism and female sub-fertility. Quantitation of HCG is used to monitor therapy, diagnose various disease states and diagnose and monitor pregnancy. Low levels of HCG in the early and late stages of pregnancy and in various disease states has prompted the development of extremely sensitive assay procedures. Clinically, radioimmunoassay methods are most frequently used due to their precision, sensitivity and cost. However, problems with specificity have been noted. Commercial preparations of HCG must meet the standards outlined in the United States Pharmacopeia (USP). The assay procedure involves a rat uterine weight bioassay. This protocol is lengthy to perform (5 days), requires the sacrifice of a large number of animals (minimum of 60 female rats per assay) and may need to be repeated if the results do not meet the statistical requirements of the assay. Due to the use of animals and the animal care facilities required, this is an expensive assay. In addition, the bioassay is not specific for HCG. Therefore, this thesis reports the analysis of two commercial preparations of HCG, as well as USP Reference Standard HCG and commercially available purified intact HCG and purified individual subunits. Various HPLC assay procedures were evaluated to determine if HPLC would be a viable alternative to the official USP bioassay. Size exclusion HPLC, using one Protein Pak 125 sw column and two Protein Pak 300 sw columns individually and in various combinations, was used to assess all the samples of HCG. Attempts to increase resolution of HCG from interfering components found in these preparations included using both 208 nm and 278 nm for ultraviolet detection, evaluation of 32 buffers as mobile phases with the Protein Pak 300 sw column, fluorescamine derivatization of HCG followed by fluorescence detection, connection of two size exclusion columns in series, and recycling on a Protein Pak 300 sw column. Further attempts to isolate HCG from its protein contaminants involved using ion exchange HPLC with a Protein Pak DEAE 5 pw column with 20 different buffers as mobile phases as well as reversed-phase HPLC with an Ultrasphere ODS column. The greatest resolution was obtained with one Protein Pak 300 sw column with a phosphate buffer (0.15 M, pH 7.0) for the mobile phase and ultraviolet detection. Latex agglutination inhibition slide tests and electrophoresis techniques were used to evaluate commercial samples of HCG and chromatographic peak eluates. Commercial HCG samples appear to contain the individual subunits of HCG and intact HCG along with impurities. The USP Reference Standard HCG contains intact HCG but also contains other ultraviolet absorbing components that were partially separated by HPLC. Electrophoresis also indicated that this HCG sample contained impurities. In addition, the purified intact HCG and purified subunit samples contained impurities, as shown by HPLC. The size exclusion HPLC assay developed using one Protein Pak 300 sw column was unable to resolve intact HCG from the beta-subunit. This assay would be useful for a qualitative assay for purity of HCG preparations. However, at present, HPLC is not a viable alternative to the USP bioassay. / Pharmaceutical Sciences, Faculty of / Graduate

An objective analytical method was developed to characterize the taste profiles of five cheese varieties. Nonvolatile water extracts of Cheddar, Edam, Gouda, Swiss, and Parmesan cheeses were analyzed by high performance liquid chromatography (HPLC) with a reversed phase column. The HPLC operating conditions were determined with Mapping Super-Simplex followed by Centroid Mapping Optimization. A ternary gradient elution system was used with an Adsorbosphere C8 column to resolve a maximum number of components. The optimum solvent volume ratio was 96.8 : 1.2 : 2.0 for trifluoroacetic acid (0.1%), acetonitrile, and methanol, with a flow rate of 1.0 mL/min. Over 50.3 min this ratio was changed to 56.3 : 30.3 : 13.4. Multivariate statistical analyses including principal component and discriminant analyses were applied to 55 peak areas from 106 cheese chromatograms. Principal component analysis reduced the dimensionality of the "data from 55 to 17 principal components, which are-combinations of the original variables, with a 26% loss of explained sample variation. Discriminant analysis on data from a single HPLC column was able to correctly classify cheeses by variety at a greater than 90% success rate. This grouping rate dropped to 64% when data from all four HPLC columns was combined, implicating large between column variations. A semi-trained sensory panel correctly classified cheeses by variety at a 63% rate. This objective method provides a lasting fingerprint of cheese products. / Land and Food Systems, Faculty of / Graduate

No description available.

The problem with which this research is concerned is the determination of inorganic anions and cations with single injection ion chromatography. Direct detection of the separated analyte ions occurs after the analyte ions have passed through ion-exchange resins where they are separated according to their affinity for the ion-exchange resin active sites. The techniques involve the use of essentially a non-suppressed ion chromatographic system followed by a suppressed ion chromatographic system. With this system it is possible to accomplish both qualitative and quantitative determinations.

The purpose of this investigation was to test the effect of sample size and carrier gas flowrate on the efficiency (relative to an analytical column) of an annular preparative-scale column. The chromatographic system for this investigation consisted of η-methyl-butyrate injections with nitrogen carrier gas and a liquid phase of Craig polyester succinate on Chromosorb W. The analytical column had an inside diameter of 0.061 inches. The preparative-scale column had an outside diameter of 2.075 inches and an inside diameter of 1.050 inches. The operating temperature for both columns was 215 degrees Fahrenheit. A sample size range of 0.1 to 3.0 milliliters was studied on the preparative-scale unit; this corresponded to a 0.2 to 3.6 microliter range on the analytical unit. Carrier gas flowrates of 4305, 8610 and 17,220 milliliters per minute were studied on the preparative-scale unit. This corresponded to flowrates of 5, 10 and 20 milliliters per minute on the analytical unit. Preparative-scale efficiencies of 20.43, 41.95 and 45.34 per cent were obtained at a sample size of 0.1 milliliter. The above efficiencies correspond to flowwates of 4305, 8610 and 17,220 milliliters per minute. As the sample size was increased to 3.0 milliliters the corresponding efficiencies dropped to 7.20, 17.71 and 27.11 per cent respectively. / Master of Science

The scope of supercritical fluid chromatography continues to enlarge. The use of open tublar and packed columns, nearly universal detectors and the introduction of new mobile phases make it more important. In this work sulfur hexafluoride is evaluated as a mobile phase for supercritical fluid chromatography. The separation of a model aromatic hydrocarbon mixture using different packed columns and operational parameters with UV as a detector is presented. The chromatographic properties of supercritical sulfur hexafluoride and supercritical carbon dioxide are compared under corresponding chromatographic parameters. / Master of Science

Cannabis sativa L. is a species of flowering plant from the Cannabaceae family which contains over 100 different phytocannabinoids and terpenes. The therapeutic effectiveness of Cannabis sativa L. depends on the cannabinoid content, and the unique aroma in this plant is produced by the terpenes. The two most widely known cannabinoids are Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD). The legalization of hemp (defined as Cannabis sativa L. < 0.3% Δ9-THC by dry mass) has flooded the market with various hemp and hemp-derived consumer products. These studies focus on using Liquid Chromatography and Gas Chromatography to survey the cannabinoid and terpene content observed for commercially popular Cherry Wine hemp cultivars. Twelve samples of Cherry Wine hemp were obtained representing three field grown hemp plants, a hemp plant grown in a controlled indoor environment, and eight cloned hemp plants also grown in a controlled indoor environment. The analyses revealed variability in the cannabinoid and terpenes contents that reflect plant genetics, daylight exposure duration, and hemp processing and storage conditions. Nitrogen was examined as a substitute carrier gas for increasingly expensive helium for the analysis of terpenes. Finally, Liquid Chromatography was also applied to evaluate the cannabinoid content versus label claims of ten Δ8-Tetrahydrocannabinol (Δ8-THC) hemp-derived consumer products. Examples of under and over reporting of cannabinoids were observed indicating potential risks to consumer safety and need for improved product regulation.