Determination of thallium is important due to its toxic effects on the environment and human health. Extremely low abundance of thallium in earth crust requires very sensitive and accurate methods for determination of this element. Although volatile compound generation is a sensitive, fast and economical method, thallium determination by this method has not been sufficiently investigated in literature, because of the fact that the formation of volatile forms of this element is a difficult task. A continuous flow volatile compound generation system was developed and parameters that affect the analytical signal were optimized. Sample solutions were acidified with 0.5 mol/L HNO3 and prepared in 0.0005% (v/v) rhodamine B and 1.0 mg/L Pd while 0.5% (m/v) NaBH4 stabilized in 0.5% (m/v) NaOH was used as reductant. Fast decomposition and unstability of thallium volatile species affected system performance negatively. Flow injection volatile compound generation studies were carried out with a special system. After optimizations, LOD and LOQ values were calculated as 12 ng/mL and 40 ng/mL according to peak height values in HNO3 medium. Similarly, in HCl medium LOD and LOQ values were calculated as 14 ng/mL and 45 ng/mL. Addition of Te and Pd to the sample solution containing co-enhancement reagent rhodamine B improved volatile compound generation efficiency in peak height by 3.6 and 9.3, respectively. Type of the acid used was affected peak heights and peak shapes of Tl+ and Tl3+ volatile species and HNO3 medium gave better results. By changing the location of introduction for Ar gas, the sources of memory effects and reasons of peak broadening were investigated. Most of the memory effects were coming from the gas-liquid separator (GLS) or before the GLS, as well as T-tube atomizer. Nature and behavior of Tl volatile species were also investigated and it was found that Tl and also Pd were generated in the form of nanoparticles. Transmission electron microscopic (TEM) measurements prove the presence of Tl nanoparticles in the analyte species transported to the atomizer by the effect of carrier Ar gas.

京都大学 / 新制・論文博士 / 博士(医学) / 乙第13579号 / 論医博第2301号 / 新制||医||1069(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 古川 壽亮, 教授 大鶴 繁, 教授 平井 豊博 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

No description available.

A novel analytical technique was developed where gaseous hydrogen selenide formed by sodium tetrahydroborate reduction is transported to and trapped on a resistively heated gold-coated W-coil atom trap for in situ preconcentration. The atom trap is held at 165 &ordm / C during the collection stage and is heated up to 675 &ordm / C for revolatilization / analyte species formed are transported to an externally heated quartz T-tube where the atomization takes place and the transient signal is obtained. For gold, a high volume gas liquid separator (HVGLS) was designed to improve the detection limit of Au down to the ng mL-1 levels. In this apparatus, analyte and reductant solutions are collected in a limited volume and volatile analyte species are formed. After separation of the volatile analyte species from liquid phase, the entire analyte vapor is sent to an atomizer. A W-coil trap was used to further decrease the detection limit. The enhancement factor for the characteristic concentration was found to be 10.7 when compared to HG-AAS performance without W-coil trap by using peak height values. Furthermore, the generation of analytically useful volatile form of Au has been studied. The flow injection generation was performed in a dedicated generator consisting of a special mixing apparatus and gas-liquid separator design. The on-line atomization in the quartz tube multiatomizer for atomic absorption (AAS) detection has been employed as the convenient atomization/detection mean. 198Au, 199Au radioactive indicator of high specific activity together with AAS measurements was used to track quantitatively the transfer of analyte in the course of generation and transport to the atomizer. In-situ trapping in GF for AAS was explored as an alternative to the on-line atomization. Transmission electron microscopy measurements proved the presence of Au nanoparticles of diameter of approximately 10 nm and smaller transported from the generator by the flow of carrier Ar. For silver, three types of GLS which are U-shaped, cylindrical and high volume gas liquid separators (HVGLS) were used to compare the sensitivities of these GLSs during Ag determination. The DL (3s) values were found as 29 ng mL-1, 0.4 ng mL-1 and 0.05 ng mL-1 for U-shaped GLS, cylindrical GLS with W-coil trap and HVGLS with W-coil trap, respectively. For indium, two types of GLS which are cylindrical and HVGLS with W-coil trap were used. The LOD and characteristic concentration were found as 148 and 317 ng mL-1 with cylindrical shape GLS. HVGLS with W-coil trap was used to improve sensitivity. In this case, LOD and characteristic concentration were found to be 0.46 and 0.98 ng mL-1, respectively. Moreover, to increase the reactivity between indium and reductant solutions, Ru(acac)3 catalyst was used. In this case, LOD and characteristic concentration were found to be 0.13 and 0.23 ng mL-1, respectively. In the case of using this catalyst, sensitivity was enhanced around 1378 fold with respect to cylindrical GLS.

Binding of volatile flavour compounds to plant proteins is known to be an issue, particularly for developers of flavoured gluten-free snacks made with pea protein. This project used a model system to describe the effects of extraction and heat on the binding of hexanal (Hex), hexyl acetate (HxAc) and 2-octanone (2-Oct) to pea protein isolate and to evaluate any resulting change in protein functionality.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work deals with the phytochemical study of mangaba, Hancornia speciosa Gomes (Apocynaceae). The first chapter deals with the role of volatile compounds from leaves and fruits. The effect of drying time on the chemical compositions of volatile oils from leaves was investigated. Thus, it was possible to verify that there is a decrease in the abundance of alcohols such as (E)-3-hexenol (68.6% fresh leaves; 13.3% after 10 days of drying), while the percentage of oxygen-containing monoterpenes such as geraniol (2.4% fresh leaves; 54.7% after 10 days of drying) is increased. On the other hand, the effect of the stage of maturity on the volatile components of mangaba fruit was investigated at three different stages. The volatile analyses showed an obvious difference, both in qualitative and relative abundance, of major components, according to stage of maturity. Thus, it became apparent that fruits at the initial stage (immature) present oxygen-containing monoterpenes, such as (Z)-linalool oxide, (E)-linalool oxide and linalool in a higher relative percentage, while esters, alcohols, aldehydes and ketones were detected at low percentages. Nonetheless, esters, alcohols, aldehydes and ketones predominated in the fruits at the final stage (mature) while the percentage of oxygen-containing monoterpenes was very much reduced. Finally, the volatile profile of the fruits at the intermediate stage showed esters, alcohols, aldehydes and ketones like those found in mature fruits, but at an intermediate percentage. In the same way, there was an intermediate percentage of oxygen-containing monoterpenes as was also observed in higher amounts in immature fruits. The second chapter deals with isolation and structure elucidation of twelve compounds from the latex of fruits of H. speciosa: 3-β-O-hexadecanoyl lupeol, 3-β-O-(3 -hydroxyhexadecanoyl) lupeol, 3-β-O-(9-octadecenoyl) lupeol, 3-β-O-octadecanoyl lupeol, 3-β-O-(3 -hydroxyoctadecanoyl) lupeol, 3-β-O-(3 -hydroxyeicosanoyl) lupeol, 3-β-O-(3 -hydroxydocosanoyl) lupeol, 3-β-O-(3 ,5 -dihydroxyeicosanoyl) lupeol, α-amyin, β-amyrin, lupeol and sucrose octaacetate. For structure elucidation of these natural compounds IR, EM and NMR techniques (1H, 13C, DEPT) were used. Finally, in the last chapter the extracts and some fractions of H. speciosa were screened for their biological activities in vitro. / Neste trabalho apresentamos os resultados sobre o estudo fitoquímico da mangabeira, Hancornia speciosa Gomes (Apocynaceae). Na primeira parte do trabalho foi investigada a composição química dos voláteis das folhas e dos frutos variando-se o tempo de secagem e o estádio de maturação, respectivamente. As análises através de CG-EM dos óleos essenciais das folhas nos permitiu observar que há mudanças significativas na percentagem relativa dos constituintes majoritários quando se varia o tempo de secagem. Desta forma, foi possível verificar um decréscimo nas percentagens dos álcoois como (E)-3-hexenol (68,6% nas folhas frescas; 13,3% após 10 dias de secagem); enquanto houve um aumento significativo no percentual dos monoterpenos oxigenados como geraniol (2,4% nas folhas frescas; 54,7% após 10 dias de secagem). Já nas análises da composição química dos voláteis dos frutos nos três estádios de maturação (verde, de vez e maduro), foi possível verificar uma clara diferenciação na proporção dos componentes principais, de acordo com o estádio de maturação. Assim, o aroma dos frutos verdes possui um teor maior de monoterpenos oxigenados como o óxido de cis-linalool, óxido de trans-linalool e linalool, enquanto a proporção de ésteres, álcoois, aldeídos e cetonas são menores. Por outro lado, na composição química dos voláteis dos frutos maduros, observamos um predomínio de ésteres, álcoois, aldeídos e cetonas, enquanto a proporção de monoterpenos oxigenados foi bastante reduzida. Já na composição dos voláteis dos frutos de vez , verificamos proporções intermediárias tanto dos ésteres, álcoois, aldeídos e cetonas quanto dos monoterpenos oxigenados como o óxido de cis-linalool, óxido de trans-linalool e linalool. Na segunda parte do trabalho, o estudo fitoquímico do látex dos frutos de H. speciosa nos permitiu o isolamento e identificação de 12 substâncias: 3-β-O-hexadecanoato de lupeoíla, 3-β-O-3 -hidroxihexadecanoato de lupeoíla, 3-β-O-9-octadecenoato de lupeoíla, 3-β-O-octadecanoato de lupeoíla, 3-β-O-3 -hidroxioctadecanoato de lupeoíla, 3-β-O-3 -hidroxiicosanoato de lupeoíla, 3-β-O-3 -hidroxidocosanoato de lupeoíla, 3-β-O-3 ,5 -diidroxiicosanoato de lupeoíla, α-amina, β-amirina, lupeol e a sacarose na sua forma peracetilada. A determinação estrutural das substâncias foi baseada na análise dos dados espectrais de EM, IV e RMN (1H, 13C e DEPT). Por fim, na terceira parte do trabalho, foram realizados ensaios para verificação de atividade biológica com os extratos e frações isoladas das várias partes da planta estudada.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work deals with the phytochemical study of mangaba, Hancornia speciosa Gomes (Apocynaceae). The first chapter deals with the role of volatile compounds from leaves and fruits. The effect of drying time on the chemical compositions of volatile oils from leaves was investigated. Thus, it was possible to verify that there is a decrease in the abundance of alcohols such as (E)-3-hexenol (68.6% fresh leaves; 13.3% after 10 days of drying), while the percentage of oxygen-containing monoterpenes such as geraniol (2.4% fresh leaves; 54.7% after 10 days of drying) is increased. On the other hand, the effect of the stage of maturity on the volatile components of mangaba fruit was investigated at three different stages. The volatile analyses showed an obvious difference, both in qualitative and relative abundance, of major components, according to stage of maturity. Thus, it became apparent that fruits at the initial stage (immature) present oxygen-containing monoterpenes, such as (Z)-linalool oxide, (E)-linalool oxide and linalool in a higher relative percentage, while esters, alcohols, aldehydes and ketones were detected at low percentages. Nonetheless, esters, alcohols, aldehydes and ketones predominated in the fruits at the final stage (mature) while the percentage of oxygen-containing monoterpenes was very much reduced. Finally, the volatile profile of the fruits at the intermediate stage showed esters, alcohols, aldehydes and ketones like those found in mature fruits, but at an intermediate percentage. In the same way, there was an intermediate percentage of oxygen-containing monoterpenes as was also observed in higher amounts in immature fruits. The second chapter deals with isolation and structure elucidation of twelve compounds from the latex of fruits of H. speciosa: 3-β-O-hexadecanoyl lupeol, 3-β-O-(3 -hydroxyhexadecanoyl) lupeol, 3-β-O-(9-octadecenoyl) lupeol, 3-β-O-octadecanoyl lupeol, 3-β-O-(3 -hydroxyoctadecanoyl) lupeol, 3-β-O-(3 -hydroxyeicosanoyl) lupeol, 3-β-O-(3 -hydroxydocosanoyl) lupeol, 3-β-O-(3 ,5 -dihydroxyeicosanoyl) lupeol, α-amyin, β-amyrin, lupeol and sucrose octaacetate. For structure elucidation of these natural compounds IR, EM and NMR techniques (1H, 13C, DEPT) were used. Finally, in the last chapter the extracts and some fractions of H. speciosa were screened for their biological activities in vitro. / Neste trabalho apresentamos os resultados sobre o estudo fitoquímico da mangabeira, Hancornia speciosa Gomes (Apocynaceae). Na primeira parte do trabalho foi investigada a composição química dos voláteis das folhas e dos frutos variando-se o tempo de secagem e o estádio de maturação, respectivamente. As análises através de CG-EM dos óleos essenciais das folhas nos permitiu observar que há mudanças significativas na percentagem relativa dos constituintes majoritários quando se varia o tempo de secagem. Desta forma, foi possível verificar um decréscimo nas percentagens dos álcoois como (E)-3-hexenol (68,6% nas folhas frescas; 13,3% após 10 dias de secagem); enquanto houve um aumento significativo no percentual dos monoterpenos oxigenados como geraniol (2,4% nas folhas frescas; 54,7% após 10 dias de secagem). Já nas análises da composição química dos voláteis dos frutos nos três estádios de maturação (verde, de vez e maduro), foi possível verificar uma clara diferenciação na proporção dos componentes principais, de acordo com o estádio de maturação. Assim, o aroma dos frutos verdes possui um teor maior de monoterpenos oxigenados como o óxido de cis-linalool, óxido de trans-linalool e linalool, enquanto a proporção de ésteres, álcoois, aldeídos e cetonas são menores. Por outro lado, na composição química dos voláteis dos frutos maduros, observamos um predomínio de ésteres, álcoois, aldeídos e cetonas, enquanto a proporção de monoterpenos oxigenados foi bastante reduzida. Já na composição dos voláteis dos frutos de vez , verificamos proporções intermediárias tanto dos ésteres, álcoois, aldeídos e cetonas quanto dos monoterpenos oxigenados como o óxido de cis-linalool, óxido de trans-linalool e linalool. Na segunda parte do trabalho, o estudo fitoquímico do látex dos frutos de H. speciosa nos permitiu o isolamento e identificação de 12 substâncias: 3-β-O-hexadecanoato de lupeoíla, 3-β-O-3 -hidroxihexadecanoato de lupeoíla, 3-β-O-9-octadecenoato de lupeoíla, 3-β-O-octadecanoato de lupeoíla, 3-β-O-3 -hidroxioctadecanoato de lupeoíla, 3-β-O-3 -hidroxiicosanoato de lupeoíla, 3-β-O-3 -hidroxidocosanoato de lupeoíla, 3-β-O-3 ,5 -diidroxiicosanoato de lupeoíla, α-amina, β-amirina, lupeol e a sacarose na sua forma peracetilada. A determinação estrutural das substâncias foi baseada na análise dos dados espectrais de EM, IV e RMN (1H, 13C e DEPT). Por fim, na terceira parte do trabalho, foram realizados ensaios para verificação de atividade biológica com os extratos e frações isoladas das várias partes da planta estudada.

L’objectif de ce travail est de démontrer que la présence de glucomannane de konjac (KGM) dans une matrice d’amidon de pomme de terre permet d’accroître sa stabilité physique sans inhiber l’encapsulation moléculaire de composés d’arôme par l’amylose. Pour cette étude, les deux polyosides choisis sont issus de tubercules de plantes abondantes dans la nature.L’amidon est connu pour interagir avec des composés volatils, soit en les piégeant dans la zone amorphe, soit en formant des complexes d'inclusion. Ce phénomène est appelé encapsulation moléculaire. Cependant, les matrices amylacées à forte teneur en eau présentent une synérèse pouvant être néfaste sur la stabilité du piégeage des composés d’arôme dans le temps. Le KGM possède une capacité à former des solutions extrêmement visqueuses. L’ajout de KGM à faible concentration (0,2 %) à une suspension d’amidon (5 %) perturbe la gélatinisation de l’amidon, accélère la rétrogradation de l’amylose et ralentit la rétrogradation de l’amylopectine. Lors d’un vieillissement accéléré, la présence de KGM assure la stabilité de la suspension d’amidon. Dans une matrice amidon – KGM, l’encapsulation moléculaire du carvacrol par l’amylose a été mise en évidence. Les complexes formés sont de type V6III. Leur formation est dépendante des conditions expérimentales. L’utilisation du propylène glycol favorise la formation de complexes amylose carvacrol. Lors d’un vieillissement accéléré, le KGM assure la stabilité du piégeage du carvacrol.La matrice amidon de pomme de terre – KGM avec un ajout du carvacrol en fin de process présente la stabilité physique du gel et la stabilité du piégeage du carvacrol les plus optimales. / The objective of this study is to demonstrate that the presence of konjac glucomannan (KGM) in a potato starch matrix enhances its physical stability without inhibiting the molecular encapsulation of aroma compounds by amylose. For that purpose, the two selected polysaccharides are from plant tubers, abundant in nature.Starch is known to interact with volatile compounds either by trapping in amorphous phase or by forming inclusion complexes. This phenomenon is called molecular encapsulation. However, at high water content, these starchy matrices exhibit syneresis that can be harmful to the stability of the aroma compounds trapping over time. KGM has the ability to form highly viscous solutions. Our results show that the addition of KGM at low concentration (0.2 %) in starch dispersion (5 %) disrupts the gelatinisation of starch, accelerates the retrogradation of amylose and delays the one of amylopectin. During accelerate aging, the presence of KGM ensures stability of starch suspensions.In starch – KGM matrix, the molecular encapsulation of carvacrol by amylose has been demonstrated. The complexes of caravacrol – amylose are V6III type structure. Their establishment is dependent on experimental conditions. The use of propylene glycol as carrier solvent of carvacrol promotes the formation of complexes between amylose and carvacrol. During accelerate aging, the presence of KGM ensures the stability of carvacrol trapping.The potato starch – KGM matrix with an addition of carvacrol at the end of the process shows the best physical stability of the gel and the best carvacrol trapping.

Consumption of cocoa and dark chocolate products has been associated with positive health outcomes including reduced onset of cardiovascular disease, inflammation, diabetes, obesity, and platelet disorders. Cocoa polyphenols, putatively responsible for these beneficial activities, are highly impacted by cocoa variety, agronomic effects and processing history. However, the difference in polyphenol concentration and composition between cocoa products originating from different hybrid clones (selected for high yield) or from different fermentation conditions is not fully understood. Detailed polyphenol characterization including determination of total polyphenol and total procyanidin concentrations, and qualitative and quantitative analysis of (mean) degree of polymerization was conducted. Significant differences in total polyphenol and procyanidin concentrations were observed between five genetic clones grown by the USDA-ARS Cocoa Germplasm Repository located in Mayagüez, Puerto Rico. To facilitate cocoa fermentation research in laboratories distant from cocoa harvesting sites, a laboratory-scale cocoa fermentation model system was developed in this study. This model system used dried, unfermented, cocoa beans and simulated pulp medium as the starting material. The model system supported growth of the essential succession of cocoa fermenting microorganisms and generated similar chemical changes to those observed in on-farm cocoa fermentation. Using this model system, the impact of inoculation with proprietary yeast strains Saccharomyces cerevisiae Lev F and Saccharomyces cerevisiae Lev B on cocoa polyphenol concentration and composition was evaluated. Inoculation with both yeast strains resulted in increased fermentation rate and Lev B inoculation resulted in higher total polyphenol and procyandin contents at the end of fermentation. Overall, the present work addressed the influence of cocoa variety selection and fermentation process conditions on the composition and concentration of polyphenols. These findings will contribute to continued efforts to develop cocoa products with optimized bioactivity and maximum disease preventative effects. / PHD / Annual worldwide cocoa production exceeds four million tons and the cocoa market impacts not only cocoa growing regions, but also countries producing cocoa products. Consumption of cocoa and dark chocolate products has been associated with positive health outcomes including reduced onset of cardiovascular disease, inflammation, diabetes, obesity, and platelet disorders. Cocoa polyphenols, compounds increasingly associated with health benefits, are highly impacted by the variety and processing history of cocoa. However, the extent to which cocoa genetic variety and processing conditions impact polyphenol concentration and composition is not fully understood. Polyphenol characterization was conducted for five genetic varieties sourced from the USDA cocoa germplasm repository located in Mayagüez, Puerto Rico and it was found that genetic variance could contribute to differences in polyphenol concentration. The main focus in this thesis was to develop laboratory cocoa fermentation model system to facilitate cocoa research in laboratories distant from the cocoa growing region. This model system used dried, unfermented cocoa beans and simulated pulp medium as the starting material. The model system was effective in that it supported growth of the essential succession of coca fermenting microorganisms and generated similar chemical changes to those observed in on-farm cocoa fermentation. This model system could be further applied to test the impact of fermentation conditions on cocoa bean quality. The potential for using yeast starter cultures to improve control and consistency of cocoa fermentation was evaluated using the model fermentation system. Yeast inoculation improved fermentation rate, and polyphenol concentration in fermented beans was higher when cocoa fermentation was inoculated with the yeast strain Saccharomyces cerevisiae Lev B. Overall, the present work addressed the influence of cocoa variety selection and fermentation process conditions on the composition and concentration of polyphenols. These findings will contribute to continued efforts to develop cocoa products optimized for maximum health benefits.

(EN) The presented dissertation thesis summarizes the new results of electrochemical generation of volatile compounds usable in atomic spectral methods. The main aim of this work is to develop and to characterize new types of electrolytic flow-through cells and to examine their possibilities of determination of arsenic, selenium and antimony by using the electrochemical hydride generation technique coupled with atomic absorption spectrometry with a quartz tube atomizer. Individual electrolytic cells were designed and constructed to comply with two important requirements. The cathode chamber of the electrolytic cell should have a minimal volume and a high efficiency of analyte conversion to the volatile hydride. Constructed electrolytic cells are divided into the construction groups and described in the experimental part. Selenium was chosen as the first analyte. The relevant working parameters (such as type, concentration and flow rate of electrolytes, generation current and carrier gas flow rate) were optimized for each newly constructed electrolytic cell. Under the optimal working parameters, the basic characteristics of selenium determination were found out by using electrochemical hydride generation. The electrolytic cells were compared to each other and with the classical electrolytic cell...