Vapor generation in atomic spectrometry is a well established technique for the determination of elements that can be volatilized by chemical reactions. In-situ trapping in graphite furnaces is nowadays one of the most popular methods to increase the sensitivity. In this study, resistively heated W-coil was used as an online trap for preconcentration and revolatilization of volatile species of Bi, Cd and Pb. The collected analyte species were revolatilized rapidly and sent to a quartz Ttube atomizer for AAS measurement. Although the nature of revolatilized species of Bi and Pb are not clear, they are probably molecular since they can be transported at least 45 cm without any significant decrease in the peak height values. However, cadmium is revolatilized from the trap surface as atoms. The experimental parameters were optimized for the highest vapor generation, trapping and revolatilization efficiencies. The concentration limits of detection calculated by the 3 of blank solution were found to be 0.0027, 0.0040 and 0.015 ng/mL for Bi (18 mL), Cd (4.2 mL) and Pb (2 mL), respectively / enhancement factors in the sensitivity were 130, 31 and 20, respectively. These values are comparable with those obtained by in-situ trapping in graphite furnaces or even ICP-MS found in the literature or better. Sensitivity can be improved further for Bi and Cd using larger sample volumes, but purification of blank is required for Pb. Certified standard reference materials were analyzed for the assessment of accuracy of developed method.

A method for determination of silver has been developed based on chemical vapour generation atomic absorption spectrometry (CVGAAS). Volatile species of silver in acidified medium were generated by the reduction of sodium tetrahydroborate / these species were sent to a flame-heated quartz tube atomizer (QTA) following isolation by using a gas-liquid separator. Flow injection (FI) was used for sample introduction. Optimization of parameters such as / concentrations of acid and NaBH4 concentration, flow rates of solutions and carrier gas were made. The influences of the well-known chemical modifier, Pd, and the effect of diethyldithiocarbomate (DDTC) were also examined. Interference study has been carried out for Ni(II), Co(II), Cu(II), Fe(III), Au(III), As(III), Pb(II), Se(IV) and Sn(II) . A detection limit of 7.5 ng mL-1 (n=11) was obtained with a 0.2 mL sample volume. With the FI-CVGAAS system 5.6 times sensitivity enhancement was achieved over flame atomic absorption spectrometry (FAAS).

Orientadores: Marco Aurelio Zezzi Arruda, Edvaldo Sabadini / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-08T04:01:39Z (GMT). No. of bitstreams: 1 Brancalion_MarcelLuis_M.pdf: 4673350 bytes, checksum: c534cc09a6e535a7053d092d88633edf (MD5) Previous issue date: 2006 / Mestrado / Quimica Analitica / Mestre em Química

Orientadores: Celio Pasquini, Joaquim de Araújo Nóbrega / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-25T12:04:34Z (GMT). No. of bitstreams: 1 Jora_ManassesZuliani_M.pdf: 4929889 bytes, checksum: f8da5d6a35fbac5ae2d05d997971561a (MD5) Previous issue date: 2013 / Resumo: A espectrometria de absorção atômica com atomização eletrotérmica (ET AAS) é adequada para a determinação de metais e semimetais, apresentando alta sensibilidade. Dentre os atomizadores eletrotérmicos, os fornos de grafite destacam-se por sua boa seletividade, exigência de pequenos volumes de amostra e baixos limites de detecção (i.e. 'mu'g L-1). Porém, esses atomizadores requerem fontes de alta potência (i.e. superiores a 2 kW), sistema de resfriamento e, ainda, apresentam alto custo. Como alternativa, o uso de superfícies metálicas têm sido objeto de pesquisa desde 1970. Dentre todos os metais empregados na fabricação de superfícies metálicas e utilizados para os estudos em ET AAS, o tungstênio é o que vem apresentando maior aplicação. Porém, a espectrometria de absorção atômica baseada em atomizadores de filamento de tungstênio (WC AAS) apresenta vários desafios relacionados ao entendimento da geração da nuvem atômica e dos efeitos de interferência observados. Dessa maneira, neste trabalho construiu-se um espectrômetro de absorção atômica com duplo filamento de tungstênio (DWC AAS), com duas configurações, uma empregando como sistema de detecção um sistema echelle/detector de carga acoplada intensificado (ICCD) e outra um sistema filtro óptico-acústico sintonizável (AOTF)/fotomultiplicadora. Essas duas configurações do equipamento foram empregadas em estudos de formação e evolução da nuvem atômica de elementos com características voláteis e refratárias (i.e. Pb e Cr). Além disso, estudou-se o efeito de Na, K, Ca e Mg, em três diferentes concentrações (i.e. 1, 10 e 100 mg L-1) sobre os perfis das nuvens atômicas de Pb e Cr. Esse estudo foi conduzido de tal forma que interferências em fase condensada e gasosa puderam ser avaliadas. Além disso, o equipamento foi empregado em medidas de temperatura na superfície do filamento e na fase gasosa / Abstract: Electrothermal atomic absorption spectrometry (ET AAS) is suitable for determination of metals and semimetals with high sensitivity. Among the existing electrothermal atomizers, graphite furnace stands out due to its selectivity, requirement of low volume of sample and low limits of detection (i.e. 'mu'g L-1). Notwithstanding, these atomizers present high cost and requires high power power supply (i.e. above 2 kW) and a cooling system. Alternatively, metallic surfaces have been studied since 1970. Among all metals employed as atomizers in ET AAS studies, tungsten has presented the best results and has found many analytical applications. However, tungsten coil atomic absorption spectrometry (WC AAS) presents several challenges related to understanding the atomic cloud generation and interferences effects. Thus, in this work, a double tungsten coil atomic absorption spectrometer (DWC AAS), with two different configurations was constructed. In one configuration, a detection system based on echelle/intensified charge-coupled device (ICCD) is employed and, in the other, an acousto-optic tunable filter (AOTF)/photomultiplier detection system is used. Both configurations were employed in the atomic cloud generation and evolution studies of Pb and Cr. Furthermore, interferences on the atomic cloud profile of Pb and Cr caused by Na, K, Ca and Mg, at three different concentrations (i.e. 1, 10 and 100 mg L-1), were studied. This study helped to evaluate the effect of condensed and gas phase interferences. Additionally, the equipment was employed to perform measures of surface and gas phase temperatures / Mestrado / Quimica Analitica / Mestre em Química

Orientador: Juliana Azevedo Lima Pallone / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-22T00:01:01Z (GMT). No. of bitstreams: 1 Oliveira_AnaAliceAndrade_M.pdf: 1712746 bytes, checksum: f7bd6bb2cad0015ebc180af686268e60 (MD5) Previous issue date: 2013 / Resumo: A partir da Resolução Nº 344, de 13 de dezembro de 2002, publicada pela Agência Nacional de Vigilância Sanitária, a fortificação de farinhas de trigo e milho com ferro e ácido fólico tornou-se obrigatória. No entanto, para garantir a eficiência do programa de fortificação, é importante obter dados sobre o consumo de ferro a partir dos alimentos fortificados e assegurar a qualidade destes produtos. Neste trabalho foi validada e aplicada uma metodologia para determinação de ferro por espectrometria de absorção atômica com chama em massas e bolos elaborados com farinha de trigo fortificada. Também foram realizadas determinações de umidade, acidez álcool solúvel e índice de peróxido, a fim de verificar a qualidade destes produtos. O teor de carbono residual nas amostras, após mineralização, foi determinado por espectrometria de emissão atômica por plasma indutivamente acoplado (ICP-OES). Os resultados revelaram que a digestão foi eficiente e que o método para determinação de ferro apresenta precisão, exatidão, linearidade e limites de detecção e quantificação adequados para aplicação em massas e bolos. Os resultados da determinação de ferro mostraram que, entre as amostras de macarrão massa seca, macarrão instantâneo, massa de pizza, massa de pastel, bolo e massa de lasanha o teor de ferro variou de 2,5 a 7,1 mg 100 g-1 (em média 5,0 mg 100 g-1), de 2,4 a 5,5 mg 100 g-1 (em média 4,3 mg 100 g-1), de 2,0 a 5,5 mg 100 g-1 (em média 3,8 mg 100 g-1), de 1,0 a 4,9 mg 100 g-1 (em média 2,9 mg 100 g-1), de 1,1 a 3,1 mg 100 g-1 (em média 2,1 mg 100 g-1) e de 0,7 a 4,7 mg 100 g-1 (em média 2,9 mg 100 g-1), respectivamente. Para o macarrão massa seca, macarrão instantâneo, massa de pizza, massa de pastel, massa de lasanha e bolo o teor de umidade variou de 9,5% a 12,3%, de 3,3% a 7,1%, de 19,5% e 29,6%, de 25,7% a 31,3%, de 26,6% a 33,1% e de 16,3% a 26,5%, respectivamente. Nas amostras de macarrão massa seca, macarrão instantâneo, massa de pizza, massa de pastel, massa de lasanha e bolo a acidez variou de 1,4 a 3,2 mL de solução 1 mol L-1 de NaOH 100 g-1, de 0,3 e 1,0 mL de solução 1 mol L-1 de NaOH 100 g-1, de 2,9 e 4,6 mL de solução 1mol L-1 de NaOH 100 g-1, de 0,9 e 6,6 mL de solução 1mol L-1 de NaOH 100 g-1, de 1,7 e 3,7 mL de solução 1 mol L-1 de NaOH 100 g-1 e de 1,3 a 2,5 mL de solução 1mol L-1 de NaOH 100 g-1. Nas amostras de macarrão instantâneo o índice de peróxido variou, em média, de 5,9 mEq kg-1 de gordura a 8,4 mEq kg-1 de gordura. Os resultados revelam que as amostras apresentam boa qualidade físico-química, entretanto, notou-se grande variação no teor de ferro nas amostras analisadas / Abstract: Brazilian Health Surveillance Agency (ANVISA) established, by resolution RDC Nº344, mandatory fortification of wheat flour and corn flour with iron and folic acid. However, to ensure the efficiency of the fortification program, it is important to get information about iron consumption from fortified food and guarantee the quality of the products. The aim of this study was to validate and apply a methodology for iron determination by flame atomic absorption in pasta and cake produced with wheat flour fortified with iron. In addition, humidity, acidity and peroxide index were determined to check the quality of the products. In order to assess the efficiency of the mineralization, residual carbon was determined by inductively-coupled plasma optical emission spectrometry. The results revealed that the mineralization was efficient and the method demonstrated accuracy, precision, linearity and adequate detection limit and quantification limit. The results of iron determination showed that the iron content of dried pasta, instant noodle, pizza dough, samosa dough, orange cake and fresh lasagna sheets ranged from 2,5 to 7,1 mg 100 g-1 (on average 5,0 mg 100 g-1), from 2,4 to 5,5 mg 100 g-1 (on average 4,3 mg 100 g-1), from 2,0 mg 100 g-1 to 5,5 mg 100 g-1 (on average 3,8 mg 100 g-1), from 1,0 to 4,9 mg 100 g-1 (on average 2,9 mg 100 g-1), from 1,1 to 3,1 mg 100 g-1 (on average 2,1 mg 100 g-1) and from 0,7 to 4,7 mg 100 g-1 (on average 2,9 mg 100 g-1),respectively. The humidity of dried pasta, instant noodle, pizza dough, samosa dough, pizza dough, fresh lasagna sheets and orange cake ranged from 9,5% to 12,3%, from 3,3% to 7,1%, from 19,5% e 29,6%, from 25,7% to 31,3%, from 26,6% to 33,1% e from 16,3% to 26,5%, respectively. The acidity of dried pasta, instant noodle, pizza dough, samosa dough, fresh lasagna sheets and orange cake ranged from 1,4 to 3,2 mL of 1 mol L-1 NaOH solution 100 g-1, from 0,3 to 1,0 mL of 1 mol L-1 NaOH solution 100 g-1, from 2,9 to 4,6 mL 1mol L-1 NaOH solution 100 g-1, from 0,9 to 6,6 mL 1mol L-1 NaOH solution 100 g-1, from 1,7 to 3,7 mL de solução 1 mol L-1 de NaOH 100 g-1 and from 1,3 to 2,5 mL 1mol L-1 NaOH solution 100 g-1, respectively. The peroxide index of instant noodle ranged from 4,0 mEq kg-1 to 12,0 mEq kg-1. The results reveal that samples had good physicochemical quality, however there was a wide variation in the products / Mestrado / Ciência de Alimentos / Mestra em Ciência de Alimentos

This diploma thesis deals with the retrieval of the content of tin in environmental media, the circulation in them and possibilities of the determination of tin in the environment. Summarizes available information on the properties of tin and its compounds, the occurrence and circulation of tin in environmental and determination of tin in environmental media, attention is paid to the determination of total tin content using method of ET-AAS. The experimental part is focused on optimization methods of determination for the ET AAS and selection of a suitable extraction procedure for determination of total tin content in soils and sediments. The best procedure for the determination of tin in the ET-AAS was applied to samples of soil, sediment and water. As the optimum matrix modifier was chosen the solution of Pd (NO3)2 in 5% ascorbic acid, the optimum pyrolysis temperature was 1400 °C and atomization temperature 2400 ° C. Neither of extraction procedures examined were found to be an appropriate procedure for the determination of tin in environmental samples and further work is necessary to optimize the method of separation.

The diploma thesis is devoted to study potential risks for living organisms resulting from inhalation of nanoparticles of chosen heavy metals. The main aim of this work is the investigation of organs from experimental white mice after their guided inhalation of lead nanoparticles. The samples of liver and lungs from these animals are taken in time periods during the inhalation experiments and processed by specific methods for their evaluation. After pressurized microwave assisted decomposition of selected samples of mice organs in high purity concentrated nitric acid the content of lead is determined by atomic absorption spectrometry with electrothermal atomization. Furthermore, the changes are monitored using the microscopy of histological slides stained with hematoxylin-eosin. The results of both approaches are evaluated and compared within the frame of this work.

The diploma thesis focuses on identifying the presence of platinum in soil samples by absorption spectroscopy. The work is divided into two parts, the theoretical part is focused on the occurrence and behavior of platinum in the environment, the fundamental chemical and physical properties of platinum, its importance in catalytic converters in cars, on solid phase extraction method and the method for the determination of atomic absorption spectrometry. The second part is the practical part, focused on the determination of the platinum amount in the soil samples in the city of Brno.

The topic of this diploma thesis was the speciation analysis of the toxicological important forms of the arsenic in urban particulate matter samples. The detection technique used in this work was atomic absorption spectrometry with quartz atomizer. Acetic acid, ammonium acetate, hydroxylamine, potassium hydroxide and sodium carbonate are recommended leaching agents for extraction of metals from urban particulate matter samples. Results of the presenting work are following: Acidic extraction reagents can be not recommended for the speciation analysis of the arsenic, because these reagents lower sensitivity of the determination of As3+ and As5+ too and destroy the quartz atomizer. Alkaline extraction reagents don't lower sensitivity of the determination of As3+ and these reagents don't destroy the atomizer, but lower sensitivity of the determination of As5+ was obtained. Recommended reagents aren't useful for extraction of the metals from urban particulate matter samples for the speciation analysis.

Multielement analysis of flue gas residues from secondary lead smelting was tested using seven decomposition methods on four different flue gas residues and certified reference materials (CRM) CPB-2 (Pb concentrate, CCRMP). The studied samples contained both silicates and also high contents of phases with Pb, primarily Pb chlorides and sulphates. Solutions prepared by various decomposition methods were analysed using ICP OES (Al, As, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Se, Si, Sn, Sr, Ti, Tl, V, Zn). Greater yields were found for most of the elements by combined decomposition (with fusion) and decomposition by sintering. Nonetheless, both methods exhibited major losses of volatile elements (As, Bi, Sb, Tl). Thus, one of these methods must always be combined with a method of decomposition in a closed system. The work also demonstrates that, for investigation of untraditional waste geological materials (e.g. flue residues from high- temperature industrial processes), it will be necessary in the future to produce new certified reference materials with anomalous chemical and mineralogical compositions, which are not currently available on the market. Laboratory extraction tests were performed on two different types of flue residues - kinetic (30 days) with ratio L/S...