Heat treated orange juice, both pasteurized and concentrate, are being increasingly consumed in the U.S. Orange juice is primarily heat treated to increase its shelf life, by curbing the growth of microorganisms; and to inactivate pectin methylesterase, which demethylates pectin and leads to cloud loss in the juice. However, because of heat processing, orange juice undergoes undesirable flavor changes that decrease its acceptability to consumers. The objectives of this study were to differentiate between fresh frozen and heat treated orange juice employing descriptive analysis, and to determine by Osme, a gas chromatography-olfactometry (GCO) method, odor active volatiles that were either lacking or created in the heat treated juice. The second objective was to determine how changes in the odor-active volatile profile of heat treated orange juice, relates to changes in the aroma and flavor intensities of the samples as assessed by descriptive analysis. Through descriptive analysis, the panel was successful in significantly (p<0.05) separating the fresh, pasteurized, and concentrate samples. Orange, orange peel, sweet, and grassy descriptors were found to be important for fresh aroma and flavor, while cooked, yam, metallic, tamarind, green bean and artificial orange descriptors were higher in heat treated samples. Using Osme, it was possible to separate fresh frozen from heat treated orange juice, on the basis of their aroma profiles. Fresh frozen samples show a higher concentration of peaks tentatively identified as gamma-butyrolactone, citral, nonanal, carvone, perillaldehyde, carvyl propinate, valencene, and other unidentified peaks possessing descriptors such as floral, lime, citrus, pine, bamboo leaf, metallic, and vinyl. Pasteurized samples show a larger concentration of peaks tentatively identified as hexanol, octanol, nerol / carveol, myrcene, 2-octanone, p-cymene, terpenen-4-ol, betacitronellol, and other unidentified peaks with descriptors such as cilantro, vinyl, melon, mushroom, and metallic. Descriptors such as orange, orange peel, sweet, grapefruit, and grassy are more pronounced in the fresh samples and are similar to the odor descriptors of Osme peaks higher in the fresh samples. Descriptors such as cooked, artificial orange, yam, metallic, tamarind, and green bean are higher in the pasteurized samples, and are similar to the odor descriptors of peaks higher in these samples. / Graduation date: 1999

Superoxide Dismutase (SOD) activity in cell-free extracts prepared from healthy mature flowers of Petunia hybrida (variety 'Hurrah') was studied. The SOD activity in the crude extracts was stable for more than one month when stored at -20 oC. It was found that pH 7.8 is optimal for SOD activity. Different flower tissues of petunia (stigma, style and ovary) at various stages of development were extracted and analysed for SOD activity. SOD activity was found to be significantly highest in the ovary tissue of dehiscent petunia flowers. Three SOD isozymes were detected after crude extracts of the different female reproductive tissues of petunia flowers were analysed on a non-denaturing polyacrylamide gel electrophoresis system. Based on a difference in the sensitivity of the SOD isoforms to H2O2 and KCN, it is suggested that Mn-SOD, Fe-SOD and Cu/Zn-SOD were present in the crude extracts of the female reproductive tissues of petunia flowers. The response of the female reproductive parts of petunia flowers was also tested under water deficiency and high temperature (35 oC) stress. The SOD activity seemed to increase more in response to the high temperature than the water deficiency stress. Intense blue staining was observed from developing younger buds, and much lower formazan deposition was detected at the later stage. This indicates the lower O2- produced during later stages mainly due to increasing SOD synthesis. DEAE cellulose chromatography was successfully used to partially purify SOD from the ovaries of petunia flowers. The characteristics of the partially purified enzyme fraction were found to be very similar to those of the crude extracts.

Several phenyl alkyl bonded phases for liquid chromatography were synthesized and characterized by liquid chromatography, gas chromatography and ¹³C nuclear magnetic resonance (NMR) spectroscopy. The chromatographic physical parameters investigated include a quantitative determination of the mobile phase volume and the stationary phase volume. The stationary phase volume was determined to be a function of the bonded moiety chain length and the chromatographic solvent system employed. The interpretation of the stationary phase volume is discussed in terms of the porous nature of the silica gel support. The chemical parameters determined include a quantitative determination of the mobile phase and stationary phase composition (which were different from each other). The selectivity of the chromatographic separations was dependent on the chemical composition and the volume of both the stationary and mobile phases. Carbon 13 NMR spectroscopy provided information about the environment of the bonded moiety in the stationary phase. The liquid-like nature of the bonded moiety was influenced by the chain length of the attached species, the choice of organic modifier, and the chemical composition of the solvents. Temperature did not appear to play a role in the line widths under the experimental conditions examined. The separation of several peptide diastereoisomers on different commercially available hydrocarbon bonded adsorbents is also reported. Select diastereoisomers of arginine vasopressin and oxytocin are extremely sensitive to differences in the composition of the stationary phase. The selectivity and elution order were dependent upon the choice of adsorbent and solvent system employed. The addition of a second organic modifier provided a method for the dynamic modification of the stationary phase. The ability to dynamically modify the stationary phase can enhance the selectivity for the separation of selected peptide diastereoisomers.

Antibodies specific for insulin and human immunoglobulin G (HlgG) were attached to controlled pore glass (CPG) particles which had been silanized with a diol-bearing silane. Up to 20 mg of antibody protein could be attached covalently to 1 gram of CPG. Such immobilized antibodies, or immunosorbents, would bind specific antigens, but not unrelated proteins, when used in a high pressure liquid chromatographic configuration. This technique was given the name "high performance immunoaffinity chromatography" (HPIC). The HPIC properties of these immunosorbents were evaluated by an equilibrium theory and were found to be comparable to batch values. An immunosorbent for HIgG antigen showed an HPIC association constant of 10⁷·⁶; the batch equilibrium constant for the same immunosorbent was 10⁷·⁸. Two different anti-insulin immunosorbents retained the intrinsic affinity (10⁶ and 10⁹) of the antibody used to make them. The total active antibody concentrations of these immunosorbents were evaluated by HPIC and batch methods with good agreement between the two. The immobilization reaction was seen to result typically in the loss of 90% of the original antibody activity. HPIC was shown to be applicable to the rapid analysis of antigens at levels as low as ng/mL. This was found to be possible in part because of the rapid forward kinetics which were assessed by HPIC. A forward rate constant of 3 X 10⁷ L·mol⁻¹·sec⁻¹ for the binding of insulin by a specific HPIC column could be determined. The possibility of HPIC fluorescence immunoassays was investigated using a highly sensitive fluorescence detector. An Eimac collimated xenon arc lamp provided sufficient power to detect picomolar levels of fluorescamine labeled insulin and other compounds. The limitations of HPIC in performing picomolar immunoassays were thus shown to be immunochemical rather than instrumental. The ability of immunoaffinity purifications to overcome these limitations was demonstrated.

The effect of the physical state and chemical composition on molecular interactions has been studied for a number of chemically modified adsorbents. During the course of the study a reaction scheme was put together for the synthesis of a particular substituted crown ether. The synthesized allyl-benzo-15crown-5, which is not reported in the literature to date, was silylated and immobilized on a silica surface. The bonded phase was characterized by UV spectroscopy and by chromatography under both "normal" and "reverse" phase conditions. UV spectroscopy was also used to elucidate the physical state of several other phenyl alkyl bonded phases. Chromatographically, the bonded crown ether phase was found to be more polar than a C₈ stationary phase. A comparison of the selectivity of the two phases revealed that the former has a better selectivity towards a homologous series of alkyl benzenes under different reverse phase conditions. The selectivity of the crown ether phase was found to be dependent on the nature of the organic modifier in the mobile phase. This dependence was considered to be added evidence for the universality of the dynamic solvated stationary phase model. Both normal and reverse phase chromatographic conditions indicated an acid-base type of interaction between the crown ether and a number of substituted phenols. This was reflected in an increase in the retention of these probes as a function of their increasing acidity. A dramatic temperature effect observed on the crown ether stationary phase under aqueous THF mobile phase, but not under aqueous MeOH, was attributed to a temperature and/or solvent-induced phase change. A hysteresis effect, also seen only with aqueous THF, indicated that the crown ether phase undergoes a solvent-assisted conformational change. Further evidences for such a change was found spectroscopically in the abrupt break in the UV absorbance of these molecules as a function of temperature, as well as the irreversibility of the absorbance of the n- π* band on cooling. UV spectroscopy of bonded phenyl alkyls showed that there are about two monolayers of water molecule strongly adsorbed to the surface and totally impermeable to lypophilic species. Evidence for the existence of a solvated crystal, or liquid crystal, like clusters was rationalized with a cooperative sorption effect which may be dependent on the reaction conditions during immobilization. Despite a significant increase in the liquid character observed as the chain length is increased to 4-7 methylene groups, the bonded clusters still appear to preserve a fairly ordered environment. The physical state of the immobilized species was found to change with the experimental conditions and the change was reflected on the selectivity of the system.

A new theory has been proposed for stationary phase formation of chemically modified chromatographic adsorbents. This theory consists of a model in which the bonded hydrocarbon moiety, silica substrate, and their respective solvation layers all participate in stationary phase formation. Stationary phase formation was found to be dependent on three parameters: (1) Solvent strength of the mobile phase components for the bonded organic moiety and the silica substrate; (2) the type of organic moiety covalently bound to the surface; and (3) the bound moiety density or surface coverage. Binary aqueous-organic mobile phases were investigated for LiChrosorb RP-8 and RP-18. For RP-8 the solica substrate played a more important role in stationary phase formation. Whereas, for RP-18 the longer bound hydrocarbon chain dominated stationary phase formation. With different organic modifiers in the mobile phase, the modifier with the larger solvent strength for the bound hydrocarbon was selectively enriched in the stationary phase solvation layer for RP-18. Ternary mobile phase systems were also investigated for RP-18. The second modifier was found to exert a large influence on stationary phase formation. Temperature's role in stationary phase formation was studied with a ternary mobile phase of 40/45/15 methanol, water, THF with RP-18. In this specific case, changing the temperature of the system did not impact on stationary phase formation. A new type of column structure was investigated. This structure involved a totally porous silica gel as compared to a column packed with totally porous silica microparticles. These silica gel columns were characterized both thermodynamically and kinectically. Under Normal Phase chromatographic conditions the silica gel column was found to have a higher selectivity but poorer efficiency for the separation of aniline from nitrobenzene than a packed column. The silica gel can be chemically modified by silane reaction and its bonded phase characteristics were investigated. The gel also showed ion-exchange properties which were investigated using sodium nitrite.

The solubility of the noble gases is temperature dependent. Other factors influencing solubility are the system pressure, the solute content of the water, and gravitational potentials. Most of the noble gases dissolved in ground water are from chemical equilibrium with the atmosphere. This equilibrium takes place in the recharge zone of the aquifer, typically in the soil. The final noble-gas concentrations are determined by the temperature, the elevation, the alteration of soil-gas composition by organisms, and soil-temperature gradients (which are in part a result of water-table depth and recharge rates). If the effects of temperature can be separated from the other influences, and if the noble-gas concentrations are not altered after recharge water enters the saturated zone, variations in recharge temperature with time may be determined by measuring the noble gases in dated ground-water samples. However, analysis of available data indicates that noble-gas concentrations frequently change after recharge. This change is usually the result of reequilibration with a biogenicgas phase produced within the aquifer, or from contact with air. In order to extend the calculation of recharge history to samples with complex histories of gas equilibrium a general equation for two stage equilibrium was derived. The variables in this equation are the initial temperature and pressure of equilibrium, the final temperature and pressure of equilibrium, and the molar water-to-gas ratio at the second equilibration. An equation of this type is constructed for each of the gases: neon, argon, krypton and xenon. These equations are solved simultaneously for four of the variables listed above while the value of one is assumed. Graphical techniques for determining which assumptions to use are presented. Ground-water samples were collected in glass tubes and analyzed by gas chromatograph-mass spectrometer, using double isotope dilution standardization. The analytical method is still developmental. Field sampling was undertaken in two locations, the Milk River aquifer of southern Alberta, Canada, and the Carrizo sand aquifer in southern Texas, in order to test the method. The preliminary data obtained may show correlation with known Holocene-Pleistocene climatic fluctuations, encouraging further development of the analytical technique and field research. Finally, a method for interpreting the climatic implications of oxygen and hydrogen isotope information from ground water in conjunction with noble-gas data is given.

Current study of separation mechanism in chromatography heavily relies on the measurement of macroscopic properties, such as retention time and peak width. This dissertation describes the vibrational spectroscopy characterization of separation processes.Raman Spectroscopic characterization of a silica-based, strong anion exchange stationary phase in concentrated aqueous solutions is presented. Spectral response of stationary phase quaternary amine is closely related to changes in interaction between counter anions and the amine functional groups as the result of anion hydration. The molecular-level information obtained will provide useful guidance for control of stationary phase selectivity.To study the effects of stationary phase pore size on separations processes, monodisperse silica particles in the sub-100 nm range are prepared and self-assembled to well-ordered, three-dimensional colloidal arrays. A modified LaMer model is proposed and demonstrated for optimization of reaction conditions that lead to uniform and spherical silica particles. This approach greatly reduces the number of training experiments required for optimization. Fast Fourier transformation of colloidal array scanning electron microscopy images indicates closely-packed hexagonal packing patterns.Using these arrays, a novel system for the measurement of molecular diffusion coefficients in nanopores is reported. This system consists of an ordered colloidal array with well-defined pore structure deposited onto an internal reflection element for in-sit collection of kinetic information by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). A mathematical model is established to extract diffusion coefficients from these data. A decrease of approximately eight orders of magnitude in molecular diffusion coefficients is observed for molecular transport in nanopores.Finally, by using this colloidal array-ATR-FTIR system and the corresponding mathematical models that describe absorption in the colloidal array, the distribution in the nanopores of the acetonitrile organic modifier in an aqueous mobile phase solvent system is determined. Based on the results of 50 nm colloidal arrays, pore surface properties have a strong effect on the distribution of organic molecules from bulk solution to the pores.

Proteins secreted or shed by tumors can be found in serum. Detecting these proteins by mass spectrometry (MS) is difficult, due to the wide dynamic range of protein concentrations in serum. To circumvent this issue, we mined the conditioned media of epithelial ovarian cancer (EOC) cell lines which is a less complex fluid to work with. We hypothesize that some of the proteins shed or secreted by EOC cell lines are similar to those secreted or shed by EOC tumors and that some of these proteins can be used as biomarkers. We mined the conditioned medium of four ovarian cancer cell lines (HTB75, TOV-112D, TOV-21G and RMUG-S) by two-dimensional liquid chromatography-mass spectrometry. Our study identified 1208, 1252, 885, and 463 proteins from the HTB-75, TOV-112D, TOV-21G, and RMUG-S cell lines respectively. In all, we identified 2039 proteins from which we focused on 420 extracellular and plasma membrane proteins. High abundance proteins such as albumin and immunoglobulins, which are problematic for serum proteomics, did not interfere with our study. Several known markers of EOC including CA-125, HE4, Mesothelin, and KLK6, were identified in this study. The list of 420 extracellular and membrane proteins was cross-referenced with the proteome of ascites fluid to generate a final list of 51 potential candidates. According to Ingenuity Pathway Analysis, two of the top 10 diseases associated with our list of 51 proteins were cancer and reproductive diseases. Of the 51 candidates, 10 proteins were selected for verification in sera from ovarian cancer patients and healthy individuals. Clusterin showed a significant difference between cancer patients and normal, with sera from cancer patients showing higher levels. Another protein, NPC2, did not show a difference in sera between cancer and normals. Protein expression studies using immunohistochemistry showed that NPC2 is highly expressed in ovarian cancer tissue and absent in normal ovarian surface epithelium. In summary, clusterin and NPC2 appear to play a role in ovarian cancer pathobiology and their role in EOC need to be studied further.

Recruitment of American eels (Anguilla rostrata) to Lake Ontario has declined rapidly over the past few decades. The commercial yellow eel fishery in Lake Ontario was closed in 2004 due to a lack of eel abundance. Researchers have been attempting to ascertain the reasons for the decline, although thus far, without definitive answers. In this thesis, the question of chemical contamination is addressed as it relates to female eel spawner quality. Spatial concentration trends of halogenated persistent organic pollutants (POPs) are described in eels collected from across eastern Canada, as well as temporal concentration trends in eels collected from a historically important area of northeastern Lake Ontario, Canada. Chlorinated POPs in eels, namely, organochlorinated pesticides, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans are all significantly less than historic values which peaked in the 1960-70s. Measured concentrations of chlorinated POPs in eels from Lake Ontario have decreased by up to 3-fold over the past three decades, and exceeded toxicity thresholds historically for surrogate species (European eel and lake trout). Thus, chlorinated POPs may have had an effect on spawner quality. Concentrations of legacy POPs in eels were dependent on their origin, with eels from highly urbanized and industrialized areas having significantly higher concentrations than eels captured in less developed regions. Similar trends were observed for polybrominated diphenyl ethers and chlorinated norbornene flame retardants. A number of emerging brominated compounds were also measured in these eels by non-target analysis including bromophenols, bromobenzenes, and bromoanisoles. This thesis demonstrates that eels are an ideal species to investigate local sources of pollution, and provide chemical data that may be used in the future, when more toxicity information is available for eels, to assess the health risks posed by accumulated chemical contaminants. / Thesis (Ph.D, Chemistry) -- Queen's University, 2013-05-23 09:27:59.593