Submitted by Marcele Costal de Castro (costalcastro@gmail.com) on 2017-10-11T15:39:41Z No. of bitstreams: 1 ELIZABETH MASSENA FERREIRA D.PDF: 2256671 bytes, checksum: 0c292929bbb0f709ecda077644b77851 (MD5) / Made available in DSpace on 2017-10-11T15:39:41Z (GMT). No. of bitstreams: 1 ELIZABETH MASSENA FERREIRA D.PDF: 2256671 bytes, checksum: 0c292929bbb0f709ecda077644b77851 (MD5) Previous issue date: 2003-02 / Este trabalho apresenta um estudo sistemático da sorção de índio de meio iodeto, utilizando espuma de poliuretano à base de poliéter comercial como extrator em fase sólida, visando à pré-concentração e/ou separação de índio de diferentes matrizes de amostras. As características físico-químicas de sorção do sistema foram investigadas por processo em batelada, apresentando rápida cinética e máxima sorção numa faixa significativa de meio ácido ou básico, com coeficientes de distribuição acima de 104 L kg-1 ([KI] ≥ 0,6 mol L-1). A análise do equilíbrio de sorção indicou o tetraiodo-indato (MInI4) como a principal espécie sorvida na matriz da espuma; os mecanismos de sorção mais prováveis foram discutidos. A isoterma de Langmuir foi ajustada com êxito sendo obtido um valor de (1,55±0,02)x10-1 mol kg-1 para a capacidade de saturação. O efeito da temperatura foi avaliado indicando um processo espontâneo e exotérmico caracterizado por sorção química. A reextração do índio da espuma com solução de HCl 1,0 mol L-1 em meio etanol 50% apresentou rápida cinética (10 minutos) e eficiência (97%). O sistema pode ser utilizado para a separação de traços de índio de grandes quantidades de Al, Fe, Zn, Ni, Co, Mn e Ga. Cd e Pb são co-extraídos. Ácido cítrico, F- e EDTA interferem na sorção do índio; tiosulfato de sódio (< 0,1 mol L-1) e ácido ascórbico (até 0,8 mol L-1) não interferem. O sistema foi avaliado na determinação de In na presença de 105 vezes Zn, Al, Fe pelo método de adição e recuperação de índio. Os elementos determinados por ICP-OES apresentaram fatores de separação, da ordem de 7,0x 102 para Zn/In, 1,0x105 para Fe/In e de 5,5x104 para Al/In, com eficiente recuperação de índio. A metodologia desenvolvida foi aplicada para determinar índio por ICP-OES em material de referência padrão de zinco metálico (NIST), apresentando concordância compatível com o valor certificado, para um nível de confiança de 95%. / This work shows a systematic study on indium iodide sorption using commercial polyether-based polyurethane foam as a solid phase extractor in order to preconcentrate and/ or separate indium from different sample matrices. The physico-chemical characteristics of the system sorption were investigated for the batch process. The system has shown rapid kinetic and maximum sorption from a meaningful range of either acid or basic medium and achieves distribution ratios above 104 L kg-1 ([KI] ≥ 0.6 mol L-1). Sorption equilibrium analysis indicates the tetraiodo-indate (MInI4) as the main species sorbed on the foam matrix; the more probable mechanisms of sorption were discussed. Langmuir isotherm was successfully fitted and a value of (1.55±0.02)x10-1 mol kg-1 was obtained for the saturation capacity. The temperature effect was evaluated and indicates a spontaneous and exothermic chemisorption process favored at low temperatures. The indium reextraction from the foam using a HCl 0.1 mol L-1 in ethanol 50% medium solution has also shown a rapid kinetic (10 minutes) and efficiency (97%). The system should be used to separate large quantities of Al, Fe, Zn, Ni, Co, Mn and Ga from trace indium. Cd and Pb are coextracted with indium. Citric acid, F- and EDTA interfere on indium sorption; sodium thiosulfate (≤ 0.1 mol L-1) and ascorbic acid (up to 0.1 mol L-1) do not interfere. The system was evaluated in the determination of indium in the presence of 105 times Zn, Al and Fe by indium addition and recovery technique. The elements determination by ICP-OES showed separation factors around 7.0x102 for Zn/In, 1.0X105 for Fe/In and of 5.5x104 for Al/In, with an efficient recovery of indium. The developed methodology was applied to determine indium in metallic zinc standard reference material (NIST) by ICP-OES and has shown compatible agreement with the certified value at a 95% confidence level.

Graphite and graphitic materials underpin a number of modern technologies such as electrodes for energy storage and conversion systems. Due to their aromatic honeycomb-type lattice and layered structure, these carbons host a rich variety of foreign elements in their interstices. Whether possessing a tubular morphology - that enables the encapsulation of inorganic compounds, or a planar texture - where anions and molecules can intercalate, the chemical analysis of graphite and graphitic materials is often confronted with the need to disintegrate the carbon matrix to quantify target elements, most often metals. However, the resilience of the sp2-hybridized carbon lattice to chemical attacks is an obstacle to its facile solubilization, a necessary step to perform some of the most common elemental analysis measurements. Over the years, a range of alternative approaches have sprung out to address this issue such as the combustion of the carbon matrix followed by the acid dissolution of its ash product. Unfortunately, none of these represents a viable method that can be applied to batteries, in great part because of the different components that make up the carbon-based electrodes. In this dissertation, a new protocol has been developed to digest graphitic materials aiming to access their elemental composition in bulk scale. The approach is based on the use of molten alkaline salts to promote the oxidation of the carbon lattice and leach out metals into a dilute acid solution. As a model sample, given the existence of standards with a matching matrix, single-walled carbon nanotubes were examined. After being subjected to the alkaline oxidation (a.k.a. fusion), they were solubilized and analyzed with Inductively Coupled Plasma-Optical Emission Spectroscopy, a widely popular tool for elemental analysis of metals. Structural analysis ensued to understand the interaction of the molten salts with the nanotubes. After evaluating the applicability of the protocol to other carbons, a more complex system was investigated, namely the carbon-based anode of an intercalation-type potassium ion battery. In this process, a direct way to quantify the mass of the alkali metal was discovered, one which makes use of complementary chemical and structural analytical tools.

Marking methods represent often an essential part of many studies which target on insect biology. These marking techniques sometimes represent the only possible way to obtain new and important informations. In the first part of the thesis I deal with individual insect labeling, which was used for marking of solitary bees and their nests as a tool of obtaining informations about nesting bee dynamics in aggregation. Our study show that nest owner replacements are very common in all four species. However, a large percentage of the nests were abandoned by the female owners before owner change. Only a part of all the nests were trully usurped on the nesting site. The true usurpations thus represent rather minor part of observed nest owner replacement situations. The bees surprisingly often abandon their nests and found the new ones. The frequent contacts of the females on a nesting site occur as a result of common nest owner replacements. High tolerance of bees to each other together with tolerance of usurpations and low level of aggression may thus represent one of the possible ways towards communality and other types of social behaviour. In the second part of the thesis I focus on the possibilities of food marking in bees. Effectivity of sugar and pollen utilization are not yet fully understood in...

This master’s thesis deals with the issue of the release of tin in canned fruit of used packaging. The theoretical part of the thesis is described canning fruit as raw material, its composition, methods of preservation, basic technological operations fruit processing, manufacture of compote, manufacture of metal packaging, marches corrosive metal packaging, chemical behavior of tin in foods and toxicity, methods for the determination of tin in foods with a focus on optical emission spectrometry with inductively coupled plasma. I the experimental part of the thesis was first ICP-OES optimized before to analysis of the 20 different samples compote purchased in chain stores. Tin concentration was determined by a fixed proportion compote. Measured concentration of tin were compared with the maximum permissible value in canned foods, which is allowed by European legislation. The tin content in all analyzed compote did not exceed the legislative limit of 200 mg/kg. The highest concentration of tin has been measured in sample conserved apricots namely 88,6 ± 2,8 mg/kg.

This Master's thesis is dealing with elementary analysis of milk. Theoretical part describes general characteristics, terminology with basic legislature and classification of milk. Large part is focused on chemical composition, especially on description of mineral substances selected for analysis in experimental part of this thesis. Choices of elementary analysis and preparation of samples for ICP-OES method conducted by other authors are also mentioned. Specification of emission spectrometry with inductively coupled plasma is crucial, a technique used for purposes of this dissertation. Experimental part deals with preparation of samples, approach of analysis and processing of measured results. The aim of this part is to compare concentration of analyzed elements in different kinds of milk. Samples from 15 different kinds of milk were used for analysis, which were determined by ICP-OES method. Results were compared to each other in discussion as well as with results from other authors.

This master’s thesis follows on bachelor’s thesis and deals with study of migration of aluminium and tin from metal containers. Manufactory of metal containers, corrosion of cans, chemical behaviour of aluminium and tin in food, its effects on health and possibilities of the determination in food and characterization of inductively coupled plasma optical emission spectrometry (ICP-OES) are described in theoretical part. In experimental part 30 different beverages in cans and glass and 6 tomato purees purchased at common stores were analysed. Measured concentrations of aluminium in beverages from cans and from glass containers were compared. It was found that beverages from cans didn’t contain higher concentrations of aluminium than beverages from glass containers. This could be caused by the fact that the aluminium is very stable metal, it has high corrosive endurance and therefore is very suitable for food packaging. Measured concentrations of tin in tomato purees were compared with the maximum permissible level of tin in canned food determined by European legislation. None of them exceed the 200 mg/kg level. All of the measured concentrations were very low, because all of the cans contained protective layer of lacquer, which gives protection against corrosion and also effectively protects from releasing of tin into the can content.

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A Baixada Santista é um dos locais mais amplamente povoados e explorados do estado de São Paulo. Nas últimas décadas, devido à intensa industrialização, vem sofrendo um intenso processo de degradação ambiental. Os despejos de resíduos industriais vêm se constituindo uma das principais fontes de contaminação por metais das águas e sedimentos do estuário santista. Os metais possuem persistência e muitos deles toxicidade em concentrações variadas, podendo ser depositados nos sedimentos e atingir a biota. Desta forma, a compreensão da importância desta contaminação é condição necessária para o planejamento de uso e ocupação do espaço costeiro. O estudo proposto constitui uma base para a compreensão do nível de contaminação por metais e As no Canal de Bertioga (SP). Foram determinados por ICP-OES os níveis de Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sc, V e Zn em amostras de sedimento superficial. O grau de contaminação dos sedimentos foi avaliado segundo o padrão de qualidade de sedimentos estabelecidos pela agência ambiental canadense (TEL e PEL), todos os valores obtidos foram abaixo do PEL, e a maioria das amostras apresentaram valores abaixo do TEL, com exceção do As, Cu e Pb. Foram calculados o Fator de Concentração (FC) e o Fator de Enriquecimento (FE) para identificar a contribuição antropogênica, os índices indicaram contaminação moderada para Cu, Pb e Zn na região próxima ao estuário de Santos, e para As próximo à cidade de Bertioga, indicando uma possível entrada desses elementos, e para os demais elementos ausência de contaminação. / The region of Santos is one of the most widely explored and populated location of the state of São Paulo. In recent decades, due to the intensive industrialization, has undergone an intense process of environmental degradation. Wastewater from industrial comes to constitute a major source of metal contamination of waters and sediments of the Santos estuary. The metals have toxicity and persistence in varying concentrations, may be deposited on sediments and reach the biota. Thus, understanding the importance of this contamination is necessary to the coastal planning. The proposed study provides a basis for understanding the level of metal contamination and As at Bertioga Channel (SP). The levels of Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sc, V and Zn in superficial sediment samples, were determined by ICP-OES. The degree of sediment contamination was evaluated according to the quality standard set by sediment Canadian environmental agency (TEL and PEL), all values were below the PEL, and most of the samples had values below the TEL, with the exception of As, Cu and Pb. Concentration Factor (CF) and Enrichment Factor (EF) were calculated to identify anthropogenic inputs, and the index indicated moderate contamination for Cu, Pb and Zn in the region near the estuary of Santos, and close to the city of Bertioga, indicating a possible entry of these elements, and absence of contamination for other elements.