Magister Scientiae - MSc / In this study two medicinal plant species, namely Galenia africana and Elytropapus rhinocerotis, the former belonging to the family Aizoceae and the latter belonging to the family Asteraceae, have been investigated and different compounds isolated and characterized. Both species are important plants used in traditional medicine in Africa and particularly in South Africa. Flavanoids are secondary metabolites found in plants. They have a protective function against UV radiation and have a defence against invading illnesses due to their important antioxidant activity. Much of the food we eat and some beverages we drink contain flavonoids. The aim of this study was to investigate the electrochemistry of flavanoids isolated from these species. / South Africa

Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / In this study we identified the contaminants present in mixtures of methyl and ethyl esters of samples obtained from alternative sources of triacylglycerols, such as: Frying oil (OF), Cottonseed oil (OSA), Scum sludge (EE), Trap grease (GCG). The esters content (TE) of the samples were determined by gas chromatography with flame ionization detector (GC-FID) according to methodology NBR 15764. The samples presented TE below 96.5% (m/m), minimum percentage established by the National Agency of Petroleum, Natural Gas and Biofuels (ANP) to characterize the mixtures as Biodiesel. The identification of fatty acids methyl or ethyl esters (FAME or FAEE) in the mixtures were performed by gas chromatography/mass spectrometry (GC/MS), observing the presence of linear unsaturated esters with eighteen carbon atoms. By thermogravimetric profile, it was observed that the OF and OSA samples presented higher contamination by compounds of high molecular mass, approximately 12.00% (m/m), corroborating TE results. Reports in the literature indicate the processes of oxidative degradation or hydrolysis as being responsible for the origin of contaminants in these types of matrices, reinforced by the values of peroxide index obtained around 196.00 meq kg-1. By the easy ambiente sonic-spray ionization mass spectrometry technique (EASI-MS), in positive mode, it was possible to attribute the presence of dimers, confirmed by m/z 625, 673 and 689 ions, in addition to diacylglycerols (DAG) and triacylglycerols (TAG). The EE and GCG samples presented higher acid values around 28.00 mg KOH g-1 with higher contamination by free fatty acids (FFA). The FFA profile was determined by EASI-MS, in negative mode, and confirmed by derivatization of the samples with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and posterior GC/MS analysis. The identified FFAs comprised a range of six to eighteen carbon atoms with the majority presence of palmitic, linoleic, oleic and stearic acid. In the optimization of the open column chromatography method (CC) for the gravimetric determination of ester and contaminant content in the esters mixtures, the use of the chromatographic column with a 6 mm internal diameter and the use of hexane:dichloromethane (7:3) to elute the esters, and the use of ethyl ether:acetonitrile (8:2) to elute the contaminants were ideal conditions obtained in the optimization of the CC method. The optimized method of CC was applied in all the samples of this work, and the apolar fraction obtained and representative of the esters had esters contents above 96.5% (m/m). / Neste trabalho foram identificados os contaminantes presentes em amostras de misturas de ésteres metílicos e etílicos obtidos a partir de fontes alternativas de triacilgliceróis, tais como: óleo residual de fritura (OF), óleo da semente de algodão (OSA), escuma de esgoto (EE), gordura da caixa de gordura (GCG). O teor de ésteres (TE) das amostras foram determinados por cromatografia gasosa com detector de ionização por chama (GC-FID) conforme a metodologia NBR 15764. As amostras apresentaram TE abaixo de 96,5% (m/m), percentual mínimo estabelecido pela Agência Nacional do Petróleo, Gás Natural e Biocombustíveis (ANP) para se caracterizar as misturas como Biodiesel. A identificação dos ésteres metílicos ou etílicos de ácidos graxos (FAME ou FAEE) nas misturas foram realizadas por cromatografia em fase gasosa/espectrometria de massas (GC/MS), observando a presença majoritária de ésteres lineares insaturados com dezoito átomos de carbono. Pelo perfil termogravimétrico, foi observado que as amostras OF e OSA apresentaram maior contaminação por compostos de alta massa molecular, aproximadamente 12,00% (m/m), corroborando o TE. Relatos na literatura apontam os processos de degradação oxidativa ou de hidrólise como sendo os responsáveis pela origem de contaminantes nestes tipos de matrizes, reforçados pelos valores de índice de peróxidos obtidos em torno de 196,00 meq kg-1. Pela técnica de ionização ambiente por sonic-spray (EASI-MS), em modo positivo, foi possível atribuir a presença majoritária de dímeros, confirmados pelos íons de m/z 625, 673 e 689, além de diacilgliceróis (DAG) e triacilgliceróis (TAG). As amostras EE e GCG apresentaram maiores índices de acidez em torno de 28,00 mg KOH g-1 com maiores contaminações por ácidos graxos livres (FFA). O perfil dos FFA foi determinado por EASI-MS, em modo negativo, e confirmado por derivatização das amostras com N,Obis( trimetilsilil)trifluoracetamida (BSTFA) e análise por GC/MS. Os FFA identificados abrangeram uma faixa de seis a dezoito átomos de carbono com a presença majoritária do ácido palmítico, linoleico, oleico e esteárico. Na otimização do método de cromatografia em coluna aberta (CC) para determinação do teor de ésteres e de contaminantes em amostras de misturas de ésteres, o uso da coluna cromatográfica com diâmetro interno de 6 mm, e o uso de hexano:diclorometrano (7:3) para eluição dos ésteres, e o uso de éter etílico:acetonitrila (8:2) para eluição dos contaminantes foram as condições ideais obtidas na otimização do método de CC. O método otimizado de CC foi aplicado em todas as amostras deste trabalho, e a fração apolar obtida e representativa dos ésteres apresentaram teores de ésteres acima de 96,5% (m/m).

Made available in DSpace on 2014-10-09T12:45:13Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:31Z (GMT). No. of bitstreams: 1 07293.pdf: 5734585 bytes, checksum: d14fa6efc5fe260e124df558d69af5bd (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

The stem bark of the protected tree species, Curtisia dentata (Burm. f.)C.A.Sm., is one of the most popular plant species harvested and traded at traditional medicine markets in South Africa. The overexploitation of C. dentata trees lead to a “Near Threatened” conservation status and the population trend is portrayed as “declining”. In the KwaZulu-Natal Province of South Africa, C. dentata is completely conservation dependent. This study is not based on drug discovery or toxicological studies, but on the concern that the stem bark of C. dentata trees are harvested, prepared into remedies and consumed as traditional medicine without knowledge regarding the chemical compounds in the stem bark, particularly since the chemical composition of C. dentata stem bark was unknown to date. Phytochemical analyses were firstly conducted to determine the chemical composition of C. dentata stem bark using various solvents and various analytical methods, and secondly, to determine how seasons and regional separation of C. dentata trees affect the chemical profiles of C. dentata stem bark from an environmental and nature conservation perspective. Plants are known to contain numerous chemical compounds. Compounds isolated from a particular plant species are therefore not the only compounds present in that species, and although a plant has proven pharmacological properties, they can still cause harm. Previous studies on C. dentata aimed at validating the plant species as a medicinal plant by examining extracts of the leaves, twigs and stem bark’s potentials against known pathogens and selected cancer cells in vitro and in vivo, and its anti-inflammatory, antioxidant and antiverotoxic properties. Four pentacyclic triterpenoids and one steroidal compound were also previously isolated from C. dentata leaves, however, the leaves are not used in traditional medicines, but were suggested as alternative for stem bark as the harvesting of leaves is less destructive. The efficacy of these compounds as therapeutic agents is, however, compromised by their low solubility in water and thus their potential to penetrate permeating biological membranes. Moreover, in vitro toxicity studies distort the picture of its actual potentials on human health as the whole human metabolome and all its processes, including uptake and phase I and phase II biotransformation are not included. In vivo toxicity studies on mammalian animal species may also not present a true picture of a chemical or extract’s toxic effects on humans as animal metabolisms differ from those of humans. The chemical composition of leaves and stem bark may furthermore also be in contrast to some extent, and therefore chemical compounds were also isolated from C. dentata stem bark in this study. Scientific studies on plant-based medicines generally involve the discovery or identification of compounds that may be beneficial, and which can be exploited in future. Chemical compounds in traditional medicines or other plant-based health products which may cause adverse effects are generally ignored. Moreover, scientific studies that consider that some compounds present in plant extracts may derive from contaminants are equally limited. Traditional plant-based medicines are neither standardized nor regulated in South Africa. Users of traditional plant-based traditional medicines therefore consume uncertain dosages of both beneficial and hazardous substances, as well as contaminants simultaneously. Certain chemical compounds are carcinogens or mutagens or have the ability to accumulate in human tissues. Adverse effects may therefore only manifest after several years of use and will subsequently not be connected to the use of a particular traditional plant-based medicine. The goal of the thesis is therefore to provide a holistic portrayal of the full spectrum of chemical compounds in extracts of C. dentata stem bark and to discuss, where literature is available, the effect(s) each chemical compound may have on human health. Moreover, this thesis investigates variations in chemical composition and concentration in individual trees, seasonal variations and variations in composition and concentrations in the stem bark of C. dentata trees from geographically distinct regions. Most unexpected was that not all C. dentata stem bark samples contained chemical compounds with known beneficial potentials at each sampling date, and that chemical compounds may be region-specific and also tree-specific, which confirms that plants produce secondary metabolites according to the needs of each individual plant. Additional insight into the chemical composition and concentration of C. dentata trees is provided by the distribution profiles of amino acids in C. dentata stem bark. Extreme variations within populations and between geographical areas support the need for the cultivation of C. dentata trees to ensure sustainable production of homogenous material for chemical homogeneity. / Environment Science / PhD. (Environment Science)

This master thesis deals with the potential influence of the waste dump Hrádek u Pacova and the wastewater treatment plant Brno – Modřice on surroundings using the optimized non-target screening method of organic pollutants in water and sediments. The experimental part is focused on the identification of organic compounds in samples of ground water from monitoring wells, the surface water from stream and pond and in sediment samples collected from streams in the vicinity of municipal waste dump. Organic compounds were also identified in water and sediment samples from the river Svratka near the municipal waste water treatment plant Modřice. The sequential liquid – liquid extraction was used for the isolation of organic compounds in water samples. Organic compounds in sediment samples were isolated by pressurized solvent extraction (PSE) with subsequent fractionation of the extract using column chromatography. Final analysis determination was performed using comprehensive orthogonal two-dimensional gas chromatography with mass spectrometric detection (GCxGC-TOF MS).

(EN) Vernix caseosa is a white creamy substance that covers the skin of a newborn. It is produced during the third trimester by the skin of the baby and remains there until the age of one or even two weeks. It is uniquely human. In utero, vernix protects the skin from maceration, during the birth it serves as a lubricant and after the delivery it protects the baby against infection and regulates the temperature. As vernix is produced in third trimester, prematurely born infants lack it and this may lead to, among other things, suffering from desiccation and therefore heat loss. It is important to study it thoroughly and to find a suitable substitute of vernix for the preterm infants. Vernix consists of lipids, proteins and 80 % water. This project is aimed at the lipids. Vernix is composed of 10 % of lipids. Basic analytical methods of pocessing vernix were searched. The methods of isolation, separation and transesterification have been optimized for the lipids. For separation, thin-layer chromatography has been chosen. The method of the lipid analysis of intact molecules by MALDI-TOF MS has been optimized for these lipids. The results were confirmed using fragmentation spectra and transesterification. Esterified lipids were measured by gas chromatography coupled with mass spectrometry detection....

Bifenilas policloradas (PCBs) são componentes de óleo ascarel, usado extensamente (no Brasil até os anos 80) como isolante em transformadores de energia devido às suas propriedades físico-químicas como estabilidade térmica e alta constante dielétrica. Apesar de ter sido proibido em todo o mundo devido à alta toxicidade dos PCBs presentes em sua composição, ainda resta grande quantidade de ascarel em circulação como resíduo \"passivo\" e resultante de contaminação em trocas dos fluidos dos transformadores, além de vazamentos. A principal forma de eliminação é por incineração, que, além de ser um processo caro, pode provocar a formação de compostos mais tóxicos, as dioxinas. Por isso é importante o monitoramento da concentração dessas substâncias, a fim de evitar maiores impactos ambientais na sua disposição, bem como em estudos de biodegradação. Esta matriz é extremamente complexa, o que torna a extração e determinação desses analitos um processo trabalhoso e difícil. Neste trabalho avaliaram-se métodos de extração e determinação de PCBs presentes na solução padrão comercial PCB Congener MIX 1, SUPELCO (PCBs 10, 28, 52, 138, 153 e 180). O desenvolvimento de métodos de extração (cromatografia em coluna, extração líquido-líquido (L-L), extração em fase sólida (SPE) e micro-extração em fase sólida - SPME) dos PCBs foi seguido da determinação, por cromatografia gasosa com detector por captura de elétrons (CG/DCE), em três matrizes diferentes: óleo ascarel, amostras provenientes de reatores anaeróbios em batelada e solo. Os métodos cuja purificação e extração diminuíram o efeito dos interferentes da matriz, como SPE - Sulfoxide, cromatografia em coluna de sílica e extração L-L com n-hexano foram validados pela avaliação dos seguintes parâmetros: linearidade e faixa de aplicação; precisão instrumental; limite de detecção, limite de quantificação e recuperação absoluta. O critério de escolha entre os métodos para extração dos PCBs do óleo que forneceram maior eficiência (cartucho SPE Sulfoxide e coluna de sílica gel, após lavagem ácida; método da adição de padrão, entre 1,0 e 4,0 mg L-1) deve considerar a disponibilidade de recursos, pois a sílica gel é mais viável economicamente do que o cartucho SPE. Os valores de R2 > 0,99 para o método de extração com sílica, mesmo tendo sido considerados apenas três pontos para a curva de calibração, atestam maior linearidade do que o método com SPE Sulfoxide (R2 entre 0,97 e 0,99). A extração L-L e determinação por CG/DCE dos PCBs (padronização interna) de amostras provenientes de reatores anaeróbios em batelada (aquosas, em matriz extremamente complexa com biomassa e espuma de poliuretano para imobilização de microrganismos) foram eficientes na faixa de concentração entre 0,05 e 0,5 mg L-1. Esse método foi adequado para monitorar PCBs em estudo de degradação anaeróbia e teste de adsorção dos PCBs em espuma; forneceu linearidade com R2 entre 0,93 e 0,96 e limites de detecção de 0,048 a 0,298 mg L-1, além de recuperação absoluta entre 14,1% e 110,7%. As condições testadas por SPME não permitiram a extração dos PCBs de óleo e de solo, principalmente devido à dessorção incompleta dos PCBs da fibra de polidimetil-siloxano, de 100 μm. / Polychlorinated biphenyls (PCBs) are components of ascarel, oil widely used as insulation (until the \'80s in Brazil) due to its physicochemical properties such as thermal stability and high dielectric constant. Despite having been banned worldwide due to the high toxicity of PCBs present in its composition, there are still lots of outstanding ascarel as \"passive\" residue and resulting contamination of fluids in transformers exchanges, plus leaks. The main form of disposal is incineration, which, besides being costly, can cause the formation of more toxic compounds, that is, dioxins. It is therefore important to monitor the concentration of these substances in order to prevent further environmental impacts in their disposal, as well as in studies of biodegradation. This is an extremely complex matrix, which makes the extraction and determination of this analytes very difficult and labor intensive. In this work we have evaluated methods of extraction and determination of the PCBs present in the standard solution Congener MIX 1, SUPELCO (PCBs 10, 28, 52, 138, 153 e 180). The extraction and cleanup developed methods which reduced the effects of interfering matrix as solid phase extraction (SPE) - Sulfoxide, column chromatography on silica and liquid-liquid (L-L) extraction with n-hexane, and solid phase microextraction (SPME) after determination of the PCBs by gas chromatography with electron capture detector (GC/ECD) were validated by assessing the following parameters: linearity and range of application; instrumental precision; detection limit; limit of quantification and absolute recovery. The criterion for choosing between the methods for extraction of PCBs from the oil with a higher efficiency (SPE cartridge Sulfoxide and silica gel column, after acid washing; using the standard addition method, between 1.0 and 4.0 mg L-1) must evaluate the availability resources, since the silica gel is more economically viable than the SPE cartridge. The R2 values > 0.99 for silica extraction method, even though it was considered only three points for the calibration curve, attested higher linearity than the method with SPE Sulfoxide (R2 between 0.97 and 0.99). The L-L extraction and determination by GC/ECD of the PCBs (internal standardization) of samples from batch anaerobic reactors (aqueous, in a very complex matrix with biomass and polyurethane foam for the immobilization of microorganisms) were efficient in the concentration range between 0.05 and 0.5 mg L-1. This method was suitable to monitor PCBs in anaerobic degradation studies and its adsorption on foam; provided R2 linearity between 0.93 and 0.96 and detection limits from 0.048 to 0.298 mg L-1, as well as absolute recovery between 14.1% and 110.7%. The conditions tested for SPME technique did not allow the extraction of the PCBs from the oil and soil, mainly due to the \"incomplete dessorption\" of PCBs from the polydimethylsiloxane fiber of 100 micron.

Bifenilas policloradas (PCBs) são componentes de óleo ascarel, usado extensamente (no Brasil até os anos 80) como isolante em transformadores de energia devido às suas propriedades físico-químicas como estabilidade térmica e alta constante dielétrica. Apesar de ter sido proibido em todo o mundo devido à alta toxicidade dos PCBs presentes em sua composição, ainda resta grande quantidade de ascarel em circulação como resíduo \"passivo\" e resultante de contaminação em trocas dos fluidos dos transformadores, além de vazamentos. A principal forma de eliminação é por incineração, que, além de ser um processo caro, pode provocar a formação de compostos mais tóxicos, as dioxinas. Por isso é importante o monitoramento da concentração dessas substâncias, a fim de evitar maiores impactos ambientais na sua disposição, bem como em estudos de biodegradação. Esta matriz é extremamente complexa, o que torna a extração e determinação desses analitos um processo trabalhoso e difícil. Neste trabalho avaliaram-se métodos de extração e determinação de PCBs presentes na solução padrão comercial PCB Congener MIX 1, SUPELCO (PCBs 10, 28, 52, 138, 153 e 180). O desenvolvimento de métodos de extração (cromatografia em coluna, extração líquido-líquido (L-L), extração em fase sólida (SPE) e micro-extração em fase sólida - SPME) dos PCBs foi seguido da determinação, por cromatografia gasosa com detector por captura de elétrons (CG/DCE), em três matrizes diferentes: óleo ascarel, amostras provenientes de reatores anaeróbios em batelada e solo. Os métodos cuja purificação e extração diminuíram o efeito dos interferentes da matriz, como SPE - Sulfoxide, cromatografia em coluna de sílica e extração L-L com n-hexano foram validados pela avaliação dos seguintes parâmetros: linearidade e faixa de aplicação; precisão instrumental; limite de detecção, limite de quantificação e recuperação absoluta. O critério de escolha entre os métodos para extração dos PCBs do óleo que forneceram maior eficiência (cartucho SPE Sulfoxide e coluna de sílica gel, após lavagem ácida; método da adição de padrão, entre 1,0 e 4,0 mg L-1) deve considerar a disponibilidade de recursos, pois a sílica gel é mais viável economicamente do que o cartucho SPE. Os valores de R2 > 0,99 para o método de extração com sílica, mesmo tendo sido considerados apenas três pontos para a curva de calibração, atestam maior linearidade do que o método com SPE Sulfoxide (R2 entre 0,97 e 0,99). A extração L-L e determinação por CG/DCE dos PCBs (padronização interna) de amostras provenientes de reatores anaeróbios em batelada (aquosas, em matriz extremamente complexa com biomassa e espuma de poliuretano para imobilização de microrganismos) foram eficientes na faixa de concentração entre 0,05 e 0,5 mg L-1. Esse método foi adequado para monitorar PCBs em estudo de degradação anaeróbia e teste de adsorção dos PCBs em espuma; forneceu linearidade com R2 entre 0,93 e 0,96 e limites de detecção de 0,048 a 0,298 mg L-1, além de recuperação absoluta entre 14,1% e 110,7%. As condições testadas por SPME não permitiram a extração dos PCBs de óleo e de solo, principalmente devido à dessorção incompleta dos PCBs da fibra de polidimetil-siloxano, de 100 μm. / Polychlorinated biphenyls (PCBs) are components of ascarel, oil widely used as insulation (until the \'80s in Brazil) due to its physicochemical properties such as thermal stability and high dielectric constant. Despite having been banned worldwide due to the high toxicity of PCBs present in its composition, there are still lots of outstanding ascarel as \"passive\" residue and resulting contamination of fluids in transformers exchanges, plus leaks. The main form of disposal is incineration, which, besides being costly, can cause the formation of more toxic compounds, that is, dioxins. It is therefore important to monitor the concentration of these substances in order to prevent further environmental impacts in their disposal, as well as in studies of biodegradation. This is an extremely complex matrix, which makes the extraction and determination of this analytes very difficult and labor intensive. In this work we have evaluated methods of extraction and determination of the PCBs present in the standard solution Congener MIX 1, SUPELCO (PCBs 10, 28, 52, 138, 153 e 180). The extraction and cleanup developed methods which reduced the effects of interfering matrix as solid phase extraction (SPE) - Sulfoxide, column chromatography on silica and liquid-liquid (L-L) extraction with n-hexane, and solid phase microextraction (SPME) after determination of the PCBs by gas chromatography with electron capture detector (GC/ECD) were validated by assessing the following parameters: linearity and range of application; instrumental precision; detection limit; limit of quantification and absolute recovery. The criterion for choosing between the methods for extraction of PCBs from the oil with a higher efficiency (SPE cartridge Sulfoxide and silica gel column, after acid washing; using the standard addition method, between 1.0 and 4.0 mg L-1) must evaluate the availability resources, since the silica gel is more economically viable than the SPE cartridge. The R2 values > 0.99 for silica extraction method, even though it was considered only three points for the calibration curve, attested higher linearity than the method with SPE Sulfoxide (R2 between 0.97 and 0.99). The L-L extraction and determination by GC/ECD of the PCBs (internal standardization) of samples from batch anaerobic reactors (aqueous, in a very complex matrix with biomass and polyurethane foam for the immobilization of microorganisms) were efficient in the concentration range between 0.05 and 0.5 mg L-1. This method was suitable to monitor PCBs in anaerobic degradation studies and its adsorption on foam; provided R2 linearity between 0.93 and 0.96 and detection limits from 0.048 to 0.298 mg L-1, as well as absolute recovery between 14.1% and 110.7%. The conditions tested for SPME technique did not allow the extraction of the PCBs from the oil and soil, mainly due to the \"incomplete dessorption\" of PCBs from the polydimethylsiloxane fiber of 100 micron.

This diploma thesis deals with actual issues of the contamination in the environment with synthetic fragrances. Musk compounds are infiltrated to many environmental components (especially an aquatic ecosystem) because of their biological persistence and the ability of accumulation. This diploma thesis is focused on the selection and the optimization of method for the determination of musk compounds in real biotic matrices (fish). The isolation of analytes was realized by PSE method and the purification of extract was realized by the method of the adsorption column chromatography. Identification and quantification of individual musk compounds was carried out by GC-MS. In conclusion were results and the contamination of fish from the river Svratka disscissed and evaluated. These fish were caught at the inflow and at the outflow of the wastewater treatment plant.

This diploma thesis was focused on the analysis of four compounds from brominated flame retardants group, namely pentabromoethylbenzene, hexabromocyclododecane, hexabromobenzene and tetrabromobisphenol A. Matrices were represented by four soil samples and four seat of fire samples. In addition, bisphenol A was also determined. First of all, process of extraction of analytes from matrices was optimized. Three different extraction techniques were tested (pressurized solvent extraction, microwave-assisted extraction and ultrasound-assisted extraction). Next step was to verify stability of target compounds in strongly acidic conditions and to optimize clean-up of extract by column chromatography. Gas chromatography with electron capture detection (GC-ECD) was chosen as an appropriate analytical method for the determination of brominated flame retardants. Bisphenol A was determined by gas chromatography with mass spectrometric detection (GC-MS). The derivatization of phenolic analytes before their final analytical determination was also essential.