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Adeeyinwo, Christina Eromowen. "Flow Injection Atomic Absorption Spectrometry : analytical characteristics of flame AAS." Thesis, Loughborough University, 1990. https://dspace.lboro.ac.uk/2134/32021.
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Flow Injection (FI) techniques for use with Atomic Absorption Spectrometry (AAS) have attracted considerable research interest for sample introduction and calibration strategies. The interest continues in on-line preconcentration and matrix modification which are carried out by the incorporation of liquid-liquid extraction, ion-exchange, immobilised reagents, gas/vapour generation and continuous precipitation-filtration devices into suitably designed manifolds. Indirect determination of inorganic anions and organic compounds is becoming routine by FI–flame AAS. The direct analysis of solid samples, which is a shortcoming of flame AAS, was recently carried out by on-line electrolytic dissolutions.
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Galgan, Vera. "Determination of selenium in biological materials by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) : applications /." Uppsala : Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200710-1.pdf.
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Arslan, Yasin. "Development Of Novel Analytical Methods For Selenium, Gold, Silver And Indium Determination Using Volatile Compound Generation, Atom Trapping And Atomic Absorption Spectrometry." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613233/index.pdf.
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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 ºC during the collection stage and is heated up to 675 º
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.
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Brancalion, Marcel Luis 1983. "Avaliação de aspectos configuracionais e analiticos da tecnica TSFFAAS." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248603.
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Orientadores: Marco Aurelio Zezzi Arruda, Edvaldo SabadiniDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Mestrado
Quimica Analitica
Mestre em Química
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Ročňáková, Ivana. "Korozní degradace hořčíkových slitin v SBF roztocích." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2012. http://www.nusl.cz/ntk/nusl-216843.
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Nowadays, magnesium alloys are used in many sectors of human activity, particularly in the aerospace and automotive industries, due to a combination of good mechanical properties and low density of magnesium. Recently, however, the attention is paid to the possibility of using magnesium alloys in the medical field, mainly due to the chemical properties of magnesium. The diploma thesis is focused on evaluating of the corrosion behavior of AZ31alloy and AZ61 alloys in SBF solutions that are solutions simulating body fluids. The alloys were subjected to immersion test in Hank’s solutions for time span from 24 to 1008 hours. The corrosion process was evaluated based on several factors: alloy composition, time and pH changes. The thesis also describes in detail the methodology for establishing magnesium and zinc by method of flame absorption spektrometry (F AAS). The determination of aluminum was carried out by atomic absorption spectrometry with electrothermal atomization (ET AAS).
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Harkabusová, Veronika. "Sledování forem arsenu v potravinách." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2008. http://www.nusl.cz/ntk/nusl-216226.
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The diploma thesis is dealing with monitoring of arsenic in foodstuffs. The aim of this thesis is the determination of arsenic in samples of fish and rice and the study of forms, in which arsenic occurs, using speciation analysis. Arsenic is known as a toxic element, but its measure of toxicity depends on the chemical form it occurs in. Arsenic is present in the environment naturally or it gets in the environment by human activities. Complete characterization of arsenic compounds is necessary to understand intake, accumulation, transport, detoxification and activation of this element in the natural environment and living systems. The field of arsenic speciation analysis has grown rapidly in recent years, because determination of the total element content is not sufficient in the case of arsenic. Speciation method was done using separation by high performance liquid chromatography and detection by atomic fluorescence spectrometry with hydride generation. Extractable arsenic was present in the form of nontoxic arsenobetaine in all analysed samples of fish. In samples of rice there was confirmed the presence of toxic inorganic species of arsenic, esspecially As (III), but their concentration was at low level.
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Kořínková, Alena. "Stanovení těžkých kovů v odpadních energetických materiálech s využitím sekvenční extrakce." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2011. http://www.nusl.cz/ntk/nusl-216736.
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Tato diplomová práce pojednává o stanovení vybraných kovů v energetických odpadech, jako je úletový popílek, škvára, struska, ložový popel, produkt odsíření apod., které pocházejí ze čtyř moravských tepláren. Extrakce kovů z energetických materiálů byla provedena Tessierovou extrakcí. Za tímto účelem byla použita extrakční činidla chlorid hořečnatý (MgCl2), octan sodný (CH3COONa), hydroxylamin hydrochlorid v kyselině octové (NH2OH.HCl v CH3COOH), peroxid vodíku v kyselině dusičné (H2O2 v HNO3) a kyselina fluorovodíková (HF). Extrakce probíhala při teplotách 25°C a 40°C. Ve všech frakcích byly stanoveny olovo, měď a kadmium s využitím atomové absorpční spektrometrie (F AAS, ET AAS) a rtuť metodou AMA 254.
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Marek, Milan. "Zhodnocení zátěže půd a sedimentů v oblasti řeky Jihlavy těžkými kovy." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2011. http://www.nusl.cz/ntk/nusl-216741.
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This diploma thesis deals with a potential contamination of hazardous metals of soil and sediments. The metals cadmium, copper, lead and mercury were chosen, their specification, limited concentration and methods of determination are also described in thesis. City Jihlava and its surroundings were chosen for evaluating pollution of the soil and sediments in this area. In collected samples of the soil and sediments presence of copper, cadmium, lead and mercury were detected via atomic absorption spectrometry (F-AAS, ET-AAS, AMA 254). The metal pollution of soils and sediments by hazardous elements in Jihlava River and in Jihlava region was evaluated.
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Sýkora, Jiří. "Využití iontoměničů pro prekoncentraci platinových kovů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2017. http://www.nusl.cz/ntk/nusl-295670.
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The aim of this thesis is the elaboration of a detailed literature review on the use of ion exchangers for the preconcentration of platinum group metals. This work contains an actual literature review on this issue. In this work you will find information about the current occurrence of platinum metals in the environment, their impact on health, properties, resources and the use. There are also described ways of decomposition, extraction and use of ion exchangers. In the experimental part this thesis deals with optimization of ion exchangers and following application of real samples from the city of Brno.
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Barreto, Inakã Silva. "Um método automático para extração em fase sólida magnética de Cd e Pb em águas e de Cd em óleo comestível e detecção por GF AAS." Universidade Federal da Paraíba, 2016. http://tede.biblioteca.ufpb.br:8080/handle/tede/9171.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
In the last decade, the extraction magnetic solid phase (MSPE) has been intense study target in Analytical Chemistry, mainly because of its potential application in sample preparation. Recently, with the development motivation automatic analytical methods, this technique has been combined with flow systems. However, the synergistic integration of MSPE with these systems is still a challenge, especially when it involves the handling of viscous matrices. In this perspective, this thesis proposes the development of an effective automated method to perform the MSPE in aqueous and oily matrices. For be applied as magnetic adsorbent nanoparticles of Fe3O4 coated with alumina and functionalized with sodium dodecyl sulfate (SDS) and 1-(2-pyridylazo)-2-naphthol (PAN) were synthesized. The nanoparticles were characterized by diffraction analysis X-ray and scanning electron microscopy, where it was confirmed that the method used to obtain the particles was adequate. Secondly, the automatic system to run the MSPE was developed. To this end an extraction chamber was made of Teflon with a quartz window on the side, where all steps of MSPE was performed without the need for any auxiliary apparatus for immobilizing the adsorbent. For generating the magnetic field in the extraction chamber, a robotic device has been developed. After these steps, the applicability of the method was demonstrated in the extraction and preconcentration of Cd and Pb in drinking water samples and Cd in edible oils, using as detection atomic absorption spectrometry graphite furnace. Factors affecting MSPE, such as pH, the amount of adsorbent, the type and concentration of the eluent and the elution time were studied. In the best experimental conditions to the sample water, the detection limit was 0.004, and 0.043 ug L-1 for Cd and Pb, respectively. Even in this array, relative standard deviations less than 3.5% were achieved with a 15-fold enrichment factor for both analytes. In the case of determination of Cd in edible oils, detection limit (0.006 ug L-1) and standard deviation (< 3.3%) was obtained satisfactorily with a 9-fold enrichment factor. Interfering studies have been performed successfully for the two determinations, not revealing significant percentage interference in determinations. The developed automatic method is simple and robust since it does not require immobilization of the adsorbent, and was successfully applied in the determination of Cd and Pb in drinking water samples and Cd in edible oils.
Na última década, a extração em fase sólida magnética (MSPE) tem sido alvo de intenso estudo na Química Analítica, principalmente em virtude do seu potencial de aplicação no preparo de amostras. Recentemente, tendo como motivação o desenvolvimento de métodos analíticos automáticos, essa técnica vem sendo combinada aos sistemas em fluxo. Contudo, a integração sinérgica da MSPE com esses sistemas ainda é um desafio, principalmente quando envolve a manipulação de matrizes viscosas. Nessa perspectiva, a presente tese propõe o desenvolvimento de um eficiente método automático para realização da MSPE em matrizes aquosas e oleosas. Para serem aplicadas como adsorvente magnético foram sintetizadas nanopartículas de Fe3O4 revestidas com alumina e funcionalizadas com dodecil sulfato de sódio (SDS) e 1-(2-piridilazo)-2-naftol (PAN). As nanopartículas foram caracterizadas através da análise de difratometria de raios-X e da microscopia eletrônica de varredura, onde confirmou-se que o método empregado para obtenção das partículas foi adequado. Num segundo momento, o sistema automático para executar a MSPE foi desenvolvido. Para isso, uma câmara de extração foi confeccionada em Teflon, com uma janela de quartzo na lateral, onde todos os passos da MSPE foram realizados sem a necessidade de qualquer aparato auxiliar para imobilizar o adsorvente. Para geração do campo magnético, na câmara de extração, um dispositivo robótico foi desenvolvido. Depois de estabelecida essas etapas, a aplicabilidade do método foi demonstrada na extração e preconcentração de Cd e Pb em amostras de água de abastecimento e de Cd em óleos comestíveis, empregando como detecção a espectrometria de absorção atômica em forno de grafite. Fatores que afetam a MSPE, tais como o pH, a quantidade de adsorvente, o tipo e a concentração do eluente e o tempo de eluição foram estudados. Nas melhores condições experimentais, para a amostra água, o limite de detecção foi 0,004 e 0,043 μg L-1 para o Cd e o Pb, respectivamente. Ainda nessa matriz, desvios padrão relativos menores que 3,5 % foram alcançados com um fator de enriquecimento de 15 vezes para ambos os analitos. No caso da determinação de Cd em óleos comestíveis, limite de detecção (0,006 μg L-1) e desvio padrão relativo (< 3,3 %) satisfatório foi obtido com um fator de enriquecimento de 9 vezes. Os estudos de interferentes foram realizados com êxito para as duas determinações, não revelando interferência percentual significativa nas determinações. O método automático desenvolvido é simples e robusto, uma vez que não requer a imobilização do adsorvente, e foi aplicado com sucesso na determinação de Cd e Pb em amostras de água de abastecimento e de Cd em óleos comestíveis.
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Katskov, DA. "Graphite filter atomizer in atomic absorption spectrometry." Elsevier, 2006. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000798.
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Graphite filter atomizers (GFA) for electrothermal atomic absorption spectrometry (ETAAS) show substantial advantages over commonly
employed electrothermal vaporizers and atomizers, tube and platform furnaces, for direct determination of high and medium volatility elements in
matrices associated with strong spectral and chemical interferences. Two factors provide lower limits of detection and shorter determination cycles
with the GFA: the vaporization area in the GFA is separated from the absorption volume by a porous graphite partition; the sample is distributed
over a large surface of a collector in the vaporization area. These factors convert the GFA into an efficient chemical reactor. The research
concerning the GFA concept, technique and analytical methodology, carried out mainly in the author's laboratory in Russia and South Africa, is
reviewed. Examples of analytical applications of the GFA in AAS for analysis of organic liquids and slurries, bio-samples and food products are
given. Future prospects for the GFA are discussed in connection with analyses by fast multi-element AAS.
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Ajayi, Olubode Olumuyiwa. "Probe atomisation in electrothermal atomic absorption spectrometry." Thesis, University of Strathclyde, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314558.
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Offley, Stephen George. "Aspects of flow injection atomic absorption spectrometry." Thesis, Loughborough University, 1992. https://dspace.lboro.ac.uk/2134/25489.
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The literature relevant to the generation of volatile hydrides for analytical atomic spectroscopy has been reviewed, with particular reference to atomic absorption spectrometry (AAS). This reveals some conflicting information concerning the nature of various interference effects and strategies to overcome them. The use of flow injection (FI) procedures has been demonstrated by several research groups, to be beneficial. A review of the literature concerning the application of FI techniques to AAS shows that there is a sustained interest in the use of such a combination for analytical purposes. In particular, an interest in the on-line coupling of chemical pretreatment of samples is evident. Atomic absorption spectrometry has a limited working range and requires frequent calibration, consequently, there is a need for a rapid, precise on-line dilution procedure. The potential of FI systems with wide bore manifold tubing for on-line dilution was assessed and found to be limited by variations in dispersion coefficient arising from differences in specific gravities between the sample and carrier fluids. This could be overcome only by the use of unrealistically high flow rates. The use of FI procedures for the generation of volatile hydrides of selenium and arsenic was investigated. Optimization studies of system parameters, including the atomization step, were undertaken which demonstrated the benefits in applying FI in hydride generation atomic absorption spectrometry (HGAAS). Analytical methods were devised and evaluated for the determination of Se in copper metal and As in nickel alloy. These procedures involved the use of an on-line matrix removal step in which potentially interfering matrix elements were retained on a strong cation exchange resin (Dowex 50W). The manifold was designed so that the FI value acted as the interface between the matrix isolation stage and the vapour generation stage, a strategy which allowed independent optimization of each stage. Location of the ion exchange resin in the sample loop of a six-port rotary valve allowed the resin to be regenerated easily and rapidly, with a throughput capability of the order of 50 h⁻¹ and permit the proposed full automation of the whole analytical procedure. In the determination of As in nickel alloy a novel stopped-flow pre-reduction step was developed to permit AsIII quantification, therefore, achieve optimum sensitivity. The two systems permitted limits of detection for Se and As of 2.1 and 3.9 ng ml⁻¹ respectively. Direct comparisons were made with existing matrix isolation systems to emphasise the benefits of system design.
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Fisher, Andrew Simon. "Reactive gases in electrothermal atomisation atomic absorption spectrometry." Thesis, University of Plymouth, 1991. http://hdl.handle.net/10026.1/1663.
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Daniels, R. Scott Carleton University Dissertation Chemistry. "Studies on mercury cold-vapor atomic absorption spectrometry." Ottawa, 1991.
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Figueiredo, Fellipe Augusto Tocchini de. "Determinação de chumbo e massa de tíbias de ratos Wistar machos expostos a 30 mg/l de chumbo na água de beber desde o período intrauterino até a idade de 28 e 60 dias." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/58/58137/tde-07022013-114750/.
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O chumbo é um metal muito tóxico e que tem ampla distribuição pela sua grande utilidade. Mesmo a exposição a baixos níveis (que não causam sintomas de intoxicação aguda) de chumbo é associada a desordens cognitivas e neurológicas. O osso é considerado o melhor marcador de exposição a chumbo. No tecido ósseo, vários elementos estão presentes, e alguns deles poderiam ter sua concentração modificada pela exposição a chumbo. Testou-se a hipótese de que haja variações nos elementos Zn e Mg nas tíbias de animais expostos a chumbo (por técnica de química analítica convencional). Testou-se também se variações em microelementos poderiam ser detectadas por técnicas semiquantitativas nas tíbias de controles e animais expostos a chumbo. O objetivo deste projeto foi caracterizar em animais expostos ao chumbo desde a gestação e controles as concentrações deste elemento no osso (tíbia) de animais de 28 e 60 dias. Além do chumbo, investigamos também a concentração de 2 outros microelementos no osso: zinco e magnésio. As medidas quantitativas de chumbo foram feitas no sangue total coletado ao final dos períodos. As medidas quantitativas de chumbo, cálcio, zinco e magnésio foram realizadas a partir de soluções ácidas obtidas pela dissolução total do osso, sendo estas utilizadas para quantificar por Espectrometria de Absorção Atômica no modo chama ou com Forno e Grafite. Mandíbulas foram análisadas em Microscopia Eletrônica de Varredura e utilizando os acessórios Eletron Dispersive Spectroscopy para os elementos mais abundantes e Wavelenght dispersive Spectroscopy para investigar por análise semiquantitativa os mais abundantes elementos inorgânicos no osso destes animais, como forma de verificar se há variações nestes microelementos nos animais expostos a chumbo em comparação com controles. Como o chumbo se concentra na superfície do esmalte, também analisou-se o esmalte de primeiros molares inferiores, a fim de verificar se era visto o sinal do elemento chumbo nestes dentes. Foram usados ratos Wistar machos de 28 e 60 dias divididos em 2 grupos: C 28D (n=5) e Pb 28D (n=5) e, C 60D (n=12) e Pb 60D (n=17). Em todas as medidas de chumbo dos grupos controle as concentrações obtidas foram próximas ao limite de detecção, e houve sempre diferença estatisticamente significante (P<0.0001) quando os controles foram comparados aos grupos expostos a chumbo. As concentrações de chumbo obtidas no sangue de animais do grupo Pb 28D foi de 8,0 ug/dl (± 1.1) e no grupo Pb 60D foi de 7,2 ug/dl (± 0.89). Houve diferença estatisticamente significante entre as massas das tíbias (aferidas em balança e também a partir da quantidade de cálcio dissolvida em solução) do grupo C 60D (0,86 g ± 0,13) e Pb 60D (0,61 g ±0,11)(p=0.0004). As concentrações de chumbo detectadas nos ossos do grupo Pb 28D foi 8,02 (± 1,12) e no grupo Pb 60D foi de 43,3ug/g (± 13,26). Concentração de zinco no osso do grupo C 60D foi 0,22 mg/g e no grupo Pb 60D foi 0,22 mg/g (p>0.05). A concentração de magnésio no osso do grupo C 60D foi de 4,89 mg/g ± 0,74 e no grupo Pb 60D foi de 4,98mg/g ±0,79 (p>0.05). Os microelementos mais abundantes detectados nas tíbias contralaterais por Microscopia Eletrônica de varredura por EDS/WDS foram cálcio, fósforo, carbono, oxigênio, magnésio, sódio e potássio, não tendo sido detectadas variações nestes elementos entre os grupos controle e expostos a chumbo de 60 dias. O chumbo foi detectado apenas na região cervical dos dentes molares por MEV-EDS, e, nesta posição, apenas na forma de óxido de chumbo (deposição extrínseca) que pode ser útil para fins forenses ou de determinação de contaminação desconhecida. As conclusões deste estudo são: Houve diferença estatisticamente significante entre as massas de osso do grupo Pb 60D e C 60D. Mesmo não havendo diferença entre as concentrações de chumbo no sangue total de animais de 28 e 60 dias, houve quantidade de chumbo 5 vezes maior nos animais Pb 60D. Não houve diferenças nas concentrações de zinco e magnésio entre controles e animais expostos a chumbo. Os microelementos mais abundantes detectados nas tibias contralaterais por Microscopia Eletrônica de varredura por EDS/WDS foram cálcio, fósforo, carbono, oxigênio, magnésio, sódio e potássio, não tendo sido detectadas variações semi-quantitativas nestes elementos. O chumbo não foi detectado nem nos grupos controle ou expostos por MEV, e nos molares só foi detectada no grupo exposto como uma deposição extrínseca.Lead is a highly toxic metal that is ubiquitous do to its great usefulness. Exposure to even low levels of lead (which do not cause symptoms of acute poisoning) is associated with cognitive and neurological disorders. Bone is considered the best marker of exposure to lead. Several chemical elements are found in bone, and some of them may have a different concentration or distribution due to exposure to lead. We tested the hypothesis that there are variations in the elements zinc and magnesium in the tibia of animals exposed to lead (being those elements determined by a conventional analytic chemistry technique). It was also tested whether variations in microelements could be detected by semiquantitative microanalysis in tibias of controls and animals exposed to lead. The objective of this project was to determine the concentration of lead in bone (tibia) of animals exposed to lead from pregnancy to day 28 and day 60. Besides lead, zinc and magnesium were also determined. Lead was also determined in whole blood collected at the end of the 2 time points. Quantitative measurements of lead, calcium, zinc and magnesium have been made in solutions obtained by dissolution of the bone by Atomic Absorption Spectrometry using flame or Graphite Furnace. Tibias were analyzed by scanning electron microscopy using the accessories Electron Dispersive Spectroscopy and Wavelength dispersive Spectroscopy for semiquantitative analysis of inorganic elements in the bone and molars of these animals. Lower molars were also analyzed by these means. Male Wistar rats aged 28 and 60 days were used in these study. In both these ages there were animals in the control (C 28D, n = 5 and C 60D, n=12) and lead exposed group (Pb 28D, n = 5 and Pb 60D, n = 17). Lead concentrations found in control groups were close to the detection limit, and there was always statistically significant differences (P <0.0001) when control groups were compared with those exposed to lead. Blood lead of groups Pb 28D and Pb 60D was 8.0 ug/dl (± 1.1) and 7.2 ug/dl (± 0.89), respectively. There was a statistically significant difference between the masses of the tibia (measured in balance and also from the amount of calcium dissolved in solution): C 60D showing 0.86 g (± 0.13 g) and 0.61 g (± 0, 11) of the Pb 60D group (p = 0.0004). Lead concentrations increased five times when the Pb 28D group was compared with the Pb 60D (8.02 and 43.3 ug/g)(p<0.0001). Zinc concentrations were not different in the C 60D (0.22 mg/g) and in the Pb 60D group (0.22 mg/g)(p>0.05). Magnesium concentrations were 4.89 mg/g in the C 60D and 4.98 mg/g in the Pb 60D (p>0.05). The most abundant trace elements detected in the contralateral tibiae by SEM-EDS/WDS were calcium, phosphorus, carbon, oxygen, magnesium, sodium and potassium and no variations in these elements were detected between the control and lead exposed groups. Lead was detected only in the cervical region of molar teeth of the lead exposed groups by SEM-EDS. This finding revealed lead in the lead oxide (extrinsic deposition) which may be useful for forensic purposes or for determining unknown contaminations. Conclusions: There was a statistically significant difference between the bone masses of the Pb 60D and C 60D groups. While there is no difference between lead concentrations in whole blood of animals 28 and 60 days, the amount of lead was 5 times higher in animals Pb 60D. There were no differences in the concentrations of zinc and magnesium between controls and lead exposed animals. The most abundant trace elements detected in the contralateral tibiae by SEM-EDS/WDS were calcium, phosphorus, carbon, oxygen, magnesium, sodium and potassium, and no semi-quantitative variations in these elements were detected in relation to exposure to lead. Lead was not detected either in control or exposed groups by SEM, and in molars it was only detected in the exposed group as an extrinsic deposition.
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De, Jager Lionel Louis. "Permanent modifiers for electrothermal atomization atomic absorption spectometry." Diss., Access to E-Thesis, 2000. http://upetd.up.ac.za/thesis/available/etd-11162006-161158/.
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Money, Stephen D. "Electrodeposition and electrodeposited modifiers in electrothermal atomic absorption spectrometry." Thesis, University of Canterbury. Chemistry, 1999. http://hdl.handle.net/10092/6090.
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The work within this thesis is directed towards optimising and expanding the application of electrodeposition-coupled-electrothermal atomic absorption spectrometry (ED-ETAAS).
The technique involves modifying the surface of the graphite furnace by in-situ electrodeposition of a noble metal. The analyte is electrodeposited onto the modifier and the spent sample matrix is aspirated from the furnace, thus separating the analyte from sample matrix components which can interfere with ETAAS analysis. The electrodeposited analyte is then determined by ETAAS.
Parameters for electrodeposition of modifier and analytes were optimised. It was shown that
ED-ETAAS could be used to determine lead, cadmium, and copper in 0.5 M NaCl media with sensitivity and detection limits similar to conventional ETAAS. The technique was used to determine copper and cadmium in seawater.
Different noble metal modifiers were compared. Palladium was shown to provide better sensitivity and thermal stabilisation than iridium or rhodium for lead determination.
ED-ETAAS.was used for the determination of inorganic mercury. The detection limit for the technique, using a 20 µL sample volume, was ca. 18 ppb (corresponding to ca. 380 pg), with a characteristic mass of 91 pg. The electrodeposited palladium modifier provided greater analyte stabilisation and sensitivity than gold or ammonium sulphide modifiers. The technique was compared with cold vapour-ETAAS, for which a detection limit of ca. 1.7 ppb was determined using an 8.4 mL sample volume. The electrodeposited palladium modifier was shown to provide superior sensitivity to palladium chloride modifier.
ED-ETAAS was examined as a technique for differentiating between free metal ions and those bound in inert and/or stable complexes. This involved selective deposition for fractionation of Bi3+, Pb2+, Ni2+ and Cu2+ in the presence of varying concentrations of EDTA. Fractionation of bismuth was possible (Bi-EDTA- is inert) but in labile systems the quantitative deposition process disturbed the solution equilibria resulting in an overestimation of the free metal concentration. In an attempted application to natural waters, problems were encountered with adsorption of fulvic acid on the furnace surface. Thus EDETAAS is not recommended as a method for fractionating metal-ligand species in natural systems.
The ED-ETAAS technique was successfully used for fractionation of arsenic species. The detection limit for arsenite determination from nitric acid media was 0.58 ppb (corresponding to 22 pg in a 39 µL sample), with a characteristic mass (peak absorbance) of 7.5 pg. Total arsenic was determined from media containing L-cysteine, with a detection limit of 1.3 ppb (51 pg) and a characteristic mass of 6.6 pg. The technique was used to determine AsIII and total arsenic in two natural waters. The ED-ETAAS technique gave the same results as two comparative techniques (ETAAS and hydride generation ETAAS) provided that peak absorbance measurements were used.
19
Hutton, Jonathan Craig Carleton University Dissertation Chemistry. "Some theoretical and experimental studies in atomic absorption spectrometry." Ottawa, 1992.
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20
Ataman, Seval. "Determination Of Thallium By Volatile Compound Generation Atomic Absorption Spectrometry." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613728/index.pdf.
Full textAbstract:
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.
21
Lei, Tian. "Selenium speciation by high performance liquid chromatography -atomic absorption spectrometry." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55507.
Full textAbstract:
Selenium has been shown to have multiple biochemical effects ranging from nutrient deficiency at low levels to toxicity at high levels. This duality of concern has led to a demand for increased numbers of highly accurate and precise determinations of selenium in biological materials. A convenient procedure was developed for determining selenoamino acids by HPLC-THG-AAS, based on the derivatization of these analytes with Sanger's reagent. Selenomethionine, selenocystine and selenocysteine (after blocking the free selenol group with phenylmercurio cation) were converted to their N-2,4-dinitrophenyl derivatives, and separated on a Nucleosil 5-NO$ sb2$ column with methanolic mobile phase containing acetic acid and triethylamine. Furthermore, an improved HPLC-AAS interface design was modified and optimized for the detection of selenium in HPLC column eluate. The new design was (i) compatible with aqueous mobile phases containing volatile buffers and (ii) provided equivalent molar response to analytes containing Se($-$II), Se(+IV) and Se(+VI). A method for simultaneously determination of selenate, selenite, selenocystine, selenomethionine and selenoethionine was developed by using the HPLC-AAS system with aqueous acetic acid containing ammonium acetate as eluate solution on the cyanopropyl column. The equivalent low ng limits of detection (1-2 ng as Se) for different oxidation states of selenium analytes were obtained using several different mobile phases and/or columns. A phenol extraction procedure for selenate, selenite, selenocystine, selenomethionine and selenoethionine was evaluated for the determination of these selenium analytes in natural waters and wheat samples. The current HPLC-AAS system provides an inexpensive alternative to conventional techniques for the determination of selenium analytes in environmental samples.
22
Ozturk, Cagla Pinar. "Determination Of Silver By Chemical Vapour Generation And Atomic Absorption Spectrometry." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605491/index.pdf.
Full textAbstract:
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 tetrahydroboratethese 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).
23
Simsek, Nail Engin. "Determination Of Boron In Water Samples By Electrothermal Atomic Absorption Spectrometry." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614868/index.pdf.
Full textAbstract:
Boron (B) is a rare element on Earth crust with a natural abundance of 0.001%. However, boron content of water and soils may be significantly high in the regions with rich boron reserves. In addition, extensive use of agrochemicals in soils as well as various natural processes increases the boron concentration in water. Despite B is an essential element for all living creatures, it may pose risks at high level exposures. World Health Organization (WHO) has recommended a daily intake of 1 to 13 mg B for adults.
Turkey has almost 70% of world boron reserves principally in four regions: Kütahya, Emet
Balikesir, Bigadiç
Eskisehir, Kirka and Bursa, Kemalpasa. The boron content of water in these regions may go up to significant levels. Therefore, it is important to determine B in drinking water from these regions. Electrothermal atomic absorption spectrometry (ETAAS) is a relatively sensitive technique for determination of boron. However, the technique suffers from formation of molecular boron compounds. Therefore, use of chemical modifiers and pyrolytically coated graphite tubes modified with refractory carbide forming elements (Ta, W, Zr, Pd, Ru, Os) were utilized to develop a reliable and sensitive method. Based on optimization studies, Tantalum (Ta) coated tube and co-injection of 5.0 µ
L 0.01 mol/L Ca(NO3)2, 5.0 µ
L 0.05 mol/L citric acid together with 15.0 µ
L sample solution prepared in 1000 mg/L Mg(NO3)2 have been chosen as optimum conditions. Optimum temperatures for pyrolysis and atomization temperatures were determined as 1100 and 2700 °
C, respectively. Under these conditions, a detection limit of 0.088 mg/L and a characteristic mass of 186 pg for 15.0 µ
L sample volume were obtained. The accuracy of the method was checked by EnviroMAT-Waste Water EU-L-1 CRM and NIST 1573a Tomato Leaves SRM analyses. Drinking water samples were collected from Balikesir, Bigadiç
and Kü
tahya, Emet and analyzed by the developed method. Samples were also analyzed by more sensitive techniques
ICP-OES and ICP-MS for a comparison study. The results are compatible with each other.
24
Cathum, Shamil J. (Shamil Jawad) Carleton University Dissertation Chemistry. "Studies on atomization of elements in graphite furnace atomic absorption spectrometry." Ottawa, 1991.
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25
Bysouth, Stephen R. "Standard and sample manipulation for calibration in flame atomic absorption spectrometry." Thesis, Loughborough University, 1988. https://dspace.lboro.ac.uk/2134/33128.
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This thesis describes a study of existing calibration methods and a comparison of them, with novel calibration and sample pre-treatment methods for flame atomic absorption spectrometry (FAAS) developed by the author. A comparison of commercially available curve fitting algorithms was carried out to show how concentration errors arise and vary, due to the use of different empirical models for the calibration curve. Novel online dilution manifolds were designed. Using flow injection and continuous flow techniques, different calibration procedures were developed to allow null methods of calibration to be used and to extend the calibration range. Methods of sample pre-treatment were developed, including online dissolution and species separation, using flow injection analysis techniques. Members of the atomic spectroscopy group of the Royal Society of Chemistry were surveyed to discover calibration practices used in commercial laboratories. Respondents were asked questions on sample type, treatment and presentation, and data reduction for calibration. During the research, several papers were published and lectures given on the topics described.
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Kaya, Murat. "Determination Of Germanium At Trace Levels By Chloride Generation Atomic Absorption Spectrometry." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/3/12605147/index.pdf.
Full textAbstract:
Trace amounts of germanium is determined by flame atomic absorption spectrometry by utilizing the vaporization of germanium tetrachloride. Using a continuous flow reactor, sample solution is mixed with concentrated hydrochloric acid and heated to 80ºC to form volatile germanium tetrachloride which can be subsequently sent to N2O-C2H2 flame AAS. The necessary conditions for the volatilization of germanium tetrachloride are investigated in detail and the applicability of the method for the determination of trace amounts of germanium in real samples and standard reference materials are presented. Detection limit of the method, based on 3s, was 0.034 ng mL-1 using a sample of 1 mL. The precision was 0.3 %, expressed as the relative standard deviation for a germanium concentration of 1 ng mL-1. Owing to the high selectivity of the proposed method, no interference effect was observed.
27
Ari, Betul. "Development Of Sensitive Analytical Methods For Thallium Determination By Atomic Absorption Spectrometry." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610531/index.pdf.
Full textAbstract:
The use of slotted quartz tube (SQT) as an atom trap in atomic absorption spectrometry (AAS) provides a more stable chemical environment for atomizationthe technique is simple and easily applicable in any laboratory. This thesis study involves application of SQT together with some other approaches to thallium determination by AAS. The first stages involve the efforts to improve nebulization efficiency of conventional flame atomic absorption spectrometry (FAAS) with and without the use of SQT. This is achieved by mixing 100 µ
L of propanol with 500 µ
L of Tl standard solution using the optimum conditions. By this method, Propanol-SQT-FAAS, 4.49 times enhancement in sensitivity has been obtained with respect to conventional FAAS, method in which the characteristic concentration was calculated as 894 ng/mL. The second stage of investigation is about the use of SQT as an atom trap, AT, preconcentration device for thallium determination. The similar technique has been successfully applied to some other analytes such as Pb, Cd, Bi and Au
detection limits at the level of ng/mL were obtained in the previous studies. In the present work, the analyte atoms are trapped on the inner surface of SQT in the presence of a lean air-acetylene flame for few minutes. After this collection step, a volume of methyl isobutyl ketone, MIBK, amounting to 10-50 microliters is introduced via conventional nebulization
this causes a momentary alteration in the flame composition and thus results in the release of trapped analyte atoms from the quartz surface. This revolatilization step is followed by a rapid atomization and transient signal was obtained. In addition to this method, a novel approach has been investigated where the inner surface of SQT was modified by using a metal coating with low volatility. For this purpose, eight different coating materials which were tungsten, palladium, molybdenum, gold, tantalum, zirconium, titanium and osmium, have been applied to the inner surface of SQT and as osmium was found to be most appropriate one, the rest of the study was continued with Os-Coated-SQT. This modification provided a better surface than quartz alone so that analyte atoms are trapped more efficiently and also released easily. Although the working principle of the Coated-SQT-AT-FAAS method is same with SQT-AT-FAAS, the conditions for SQT-AT-FAAS and Os-Coated-SQT-AT-FAAS methods were optimized seperately. Limit of detections, 3s/m, has been found to be 38 ng/mL and 3.5 ng/mL for these cases, respectively. While the SQT-AT-FAAS method has provided 92 fold enhancement, the Os-Coated-SQT-AT-FAAS method has provided a 319 fold sensitivity improvement with respect to conventional FAAS method.
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Tan, Yanxi. "Novel approaches to the determination of trace elements by atomic absorption spectrometry." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0008/NQ30399.pdf.
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Absalan, Ghodratollah Carleton University Dissertation Chemistry. "Atomic absorption spectrometry with atomization by cathodic sputtering in a glow discharge." Ottawa, 1996.
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BORGES, RENATO MARÇULLO. "DETERMINATION OF SN IN HUMAN MILK BY GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROMETRY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2008. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=14735@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROO estanho é um metal de ocorrência natural que é extraído do minério de cassiterita na forma de SnO2. É lançado na natureza através de fontes naturais e antrópicas e ocorre na natureza tanto na forma inorgânica, quanto orgânica. Quanto menor a cadeia orgânica associada ao metal, maior a toxicidade do composto. Compostos orgânicos podem penetrar na membrana celular e interromper a fosforilação oxidativa e danificar as mitocôndrias. Podem ser ainda genotóxicos e imunotóxicos. O leite humano é a principal fonte de alimentação e nutrição para recém-nascidos, e é encorajada até os 2 anos de idade. Entretanto, é também a principal fonte de exposição de substâncias exógenas para bebês, incluindo o estanho e seus compostos, já que pode ser a rota de excreção de poluentes ambientais oriundos da mãe. A determinação direta do leite por EAA-FG é interessante do ponto de vista analítico pois reduz o tempo de preparação e a possibilidade de contaminação da amostra. Neste trabalho, foi utilizado um forno de grafite com aquecimento transversal. Curvas de pirólise e atomização levaram a temperaturas de pirólise e atomização de 1300 e 2200ºC, respectivamente, usando um volume de amostra de 20 µL. Os melhores resultados foram obtidos com a diluição 1+1 em HNO(3) 0,2% v/v e com a massa de 10+5 μg de paládio+magnésio, para um volume de 10 μL. Em todos os casos, a atenuação de fundo foi adequada para o corretor baseado no efeito Zeeman. A curva analítica foi linear até 300 µg.L-1, tanto no meio aquoso quanto na presença da matriz, entretanto a calibração teve que ser realizada com a adição de soluções de calibração à matriz. O limite de detecção (n=10, k=3) foi de 0,6 μg Sn.L(-1) na amostra original. Foi verificado que a presença de Cl(-1) e Ca(+2) em concentrações acima de 100 e 40 mg.L(-1), respectivamente, depreciam fortemente o sinal de estanho. Por outro lado, o aumento do sinal de estanho ocorre devido a presença de P em concentrações que variam entre 5 e 150 mg.L(-1). Recuperações maiores que 95% de iSn no leite humano foram obtidas como parte do estudo de calibração. A metodologia desenvolvida provou ser adequada para a determinação de Sn, quando na forma de MMT, através da calibração de iSn como analito de calibração.
Tin is a metal of natural occurrence which is mainly extracted from the mineral cassiterite, SnO2. Tin may be released to the atmosphere from both natural and anthropogenic sources. In nature, it occurs in both inorganic and organic forms, and the shorter the organic chain associated to the metal, the higher the toxicity of the compound. Organotin compounds can penetrate cell membranes and cause damage to cell, interrupt oxidative phosphorylation and damage mitochondria. They can be immunotoxic and genotoxic. Human milk is the ideal food for newborns due to its composition and availability. Human milk is the fundamental food for infants, thus breast feeding is greatly encouraged up to 2 years. However, it is also the major source of exposition to exogenous substances for newborns, including tin and its compounds, since breast milk can also be a route of maternal excretion of undesired environmental pollutants. The direct GF AAS analysis of products such as milk is very attractive, due to the inherent simplicity, and decrease in the sample preparation time and contamination chances. In the present work, a transversally heated graphite atomizer was used. Pyrolysis and atomization temperatures curves led to pyrolysis and atomization temperatures of 1300 and 2200ºC, respectively, using a sample volume of 20 µL. The use of a 1+1 dilution factor using 0.2% v/v HNO(3) as diluent showed to be the best choice, as well as a modifier mass of 10+5 µg of palladium+magnesium, respectively. The modifier solution volume was 10µL. In all cases, the background attenuation was well within the limits of the Zeeman effect based background corrector. The analytical curve was linear up to 300 µg L(-1), in both aqueous medium as well as in the presence of the matrix. Calibration had to be performed with matrix matched calibration solutions, using a blank level sample. The limit of detection (n=10, k=3) in the original sample was 0.6 µg L(-1). It was verified that Cl(-1) and Ca(2) + influence on tin absorbance signal is markedly depreciated at concentrations above 100 and 40 mgL(-1), respectively. On the other hand, the increase of tin signal is caused by the presence of P in concentrations between 5 and 150 mg.L(-1). In a calibration study, recovery was higher than 95% in human milk. The methodology was able in determine Sn, as MMT, when iSn is used for the calibration.
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Menemenlioglu, Ipek. "Electrochemical Hydride Generation And Atom Trapping Atomic Absorption Spectrometry For Determination Of Antimony." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605018/index.pdf.
Full textAbstract:
ABSTRACT
ELECTROCHEMICAL HYDRIDE GENERATION AND ATOM TRAPPING ATOMIC ABSORPTION SPECTROMETRY FOR DETERMINATION OF ANTIMONY
Menemenlioglu, ipek
M.S., Department of Chemistry
Supervisor: Prof. Dr. O. Yavuz Ataman
June 2004, 82 pages
Electrochemical hydride generation is a suitable alternative to common hydride generation by NaBH4 which is widely used for the detection of volatile elements such as As, Se, Sb, Sn, Bi, Ge, Te and Pb. In this study, a thin-layer flow through electrochemical cell was designed. Lead and platinum foils were employed as cathode and anode materials, respectively, for the generation of antimony hydride. Argon was used as the carrier gas. The inlet arm of the conventional quartz tube atomizer was used for on-line preconcentration of generated hydrides. A portion of the inlet arm was heated externally to the collection temperature for trapping the analyte species which were generated electrochemically. For the revolatilization of the trapped species, the trap was further heated to the revolatilization temperature and hydrogen gas was introduced into the system 10 seconds afterwards. The experimental operation conditions for electrochemical hydride generation which include the acidities and flow rates of catholyte and anolyte solutions, carrier gas flow rate and the applied electric current, were optimized. For trapping, collection and revolatilization temperatures and hydrogen flow rates were optimized. Analyses of standard reference materials were performed to check the accuracy of the proposed method. 3σ
limit of detections were found as 1.03 ng ml-1 and 0.053 ng ml-1 with and without employing the trap, respectively. The trap has provided 20 fold sensitivity improvement.
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Yildiran, Ahmet. "Electrochhemical Hydride Generation And Tungsten Trap Atomic Absorption Spectrometry For Determination Of Antimony." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610155/index.pdf.
Full textAbstract:
Electrochemical hydride generation is an alternative technique to the chemical hydride generation by NaBH4 which is widely used for atomic spectrometric determination of volatile elements such as As, Bi, Ge, Pb, Sb, Se, Sn and Te. The aim of this research has been to develop an analytical technique at the level of ng/L for determination of antimony by using a
simple and inexpensive AA spectrometer and the other parts that can be built in any laboratory. Carbon rod and platinum foil were used as cathode and anode materials, respectively, for the generation of antimony hydride. Argon was used as the carrier gas. Zr coated W-coil was used for on-line
preconcentration of generated hydrides. A new apparatus independent from quartz T-tube atomizer was constructed and used to contain the atom trap. Zr coated W-trap was heated to the collection temperature for trapping the analyte species generated electrochemically. For the revolatilization of the trapped species, the trap was further heated to the revolatilization temperature. Revolatilized species were transported to a flame-heated quartz tube atomizer where the analytical signal was recorded. Duringcollection and revolatilization steps hydrogen gas was introduced into the system to prevent the oxidation of atom trap.
The experimental operation conditions for electrochemical hydride generation and atom trapping were optimized. 3σ
limit of detections were found to be 0.012 ng/mL and 0.41 ng/mL with and without using trap, respectively. The trap has provided 34 fold sensitivity improvement as compared with the electrochemical hydride generation alone. The interferences of some hydride forming elements and some transition metals on electrochemical hydride generation with and without employing the trap were investigated. Analysis of standard reference material was performed to check the accuracy of the proposed method.
33
Delgado, Ana H. (Ana Herminia) Carleton University Dissertation Chemistry. "Studies on electrothermal atomization from graphite and metal surfaces in atomic absorption spectrometry." Ottawa, 1985.
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34
Headrick, Kurt Lee Carleton University Dissertation Chemistry. "Atomic absorption spectrometry with sample atomization by cathodic sputtering in a glow discharge." Ottawa, 1991.
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35
Appleton, J. M. H. "Applications of dispersion in unsegmented flowing streams to calibration in atomic absorption spectrometry." Thesis, Loughborough University, 1985. https://dspace.lboro.ac.uk/2134/33223.
Full textAbstract:
Atomic absorption spectrometers require calibration because no absolute mathematical relationship exists between the analytical signal and the analyte concentration. The calibration function is complex, depending upon instrument parameters, operating conditions and the chemical nature of the sample matrix. Recalibration is necessary whenever these change. Because existing methods of calibration are tedious and sometimes inaccurate, alternatives are sought. Rapid, automated calibration is particularly attractive. The prospects of achieving it using concentration gradients generated in flowing streams, with microcomputer data processing, were investigated.
36
Zayas-Cruz, Jorge I. "Studies on the atomization mechanism of selenium in graphite furnace atomic absorption spectrometry /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu148758688918748.
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Al-Maawali, Sabah (Sabah Mohamed Amer) Carleton University Dissertation Chemistry. "Studies on electrothermal atomization in graphite furnace atomic absorption spectrometry and electrothermal vaporization inductively coupled plasma mass spectrometry." Ottawa, 1991.
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38
Blais, Jean-Simon. "HPLC-AAS interfaces for the determination of ionic alkyllead, arsonium and selenonium compounds." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74637.
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Three direct interfaces for coupling high performance liquid chromatography (HPLC) with atomic absorption spectrometry (AAS) were developed and optimized for the determination of ionic organolead, organoselenium and organoarsenic compounds. The first all-quartz interface consisted of a thermospray nebulizer and a flame microatomizer in which ionic alkyllead analytes (R$ sb{ rm n}$Pb$ sp{ rm (4-n)+};$ R = CH$ sb3,$ C$ sb2$H$ sb5)$ were atomized by a methanol (from HPLC eluent)-oxygen kinetic flame, and channeled in a quartz tube (atom keeper) mounted into the AAS optical beam. Alternately, the classical electrothermal atomization technique for organolead species (quartz furnace under hydrogen atmosphere) was coupled with a post-column derivatization-volatilization apparatus based on the ethylation of ionic alkylleads by sodium tetraethylborate. The limits of detection provided by these two approaches were 1.0-3.4 ng and 0.10-0.15 ng, respectively. Arsonium ((CH$ sb3) sb3$RAs$ sp+;$ R = CH$ sb3,$ CH$ sb2$CH$ sb2$OH, CH$ sb2$COOH) and selenonium ((CH$ sb3) sb2$RSe$ sp+;$ R = CH$ sb3,$ CH$ sb2$CH$ sb2$OH) species were quantified using a novel HPLC-AAS approach based on a direct coupling of three processes: thermospray nebulization, thermochemical hydride generation using hydrogen gas, and diffuse flame atomization. Direct evidences for the thermochemical hydride generation process was obtained by injecting (CH$ sb3) sb3$SeI and SeO$ sb2$ into the interface and capturing the gaseous end products in liquid chemical traps specific for SeH$ sb2$ and Se(IV). Both analytes were derivatized to SeH$ sb2$ only in the presence of hydrogen in the interface. Reverse- and normal-phase high pressure liquid chromatographic methods were also developed and adapted for the HPLC-AAS analyses of alkyllead, arsonium and selenonium compounds in real samples. The limit of detection of the arsonium and selenonium cations were 7.6-13.3 ng and 31.0-43.9 ng, respectively.
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Erdem, Arzu Eroğlu Ahmet E. "Use Of Different Gold Amalgamation Techniques In Mercury Determination By Cold Vapor Atomic Absorption Spectrometry/." [s.l.]: [s.n.], 2005. http://library.iyte.edu.tr/tezler/master/kimya/T000354.pdf.
Full textAbstract:
Thesis (Master)--İzmir Institute of Technology, İzmir, 2005.Keywords: Mercury, atomic absorption spectrometry, gold, amalgamation, cold vapor. Includes bibliographical references (leaves 48-51).
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Akay, Pinar. "Inorganic Antimony Speciation Using Tungsten Coil Atom Trap And Hydride Generation Atomic Absorption Spectrometry." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611543/index.pdf.
Full textAbstract:
Antimony is a toxic element which is mostly found in two oxidation states (III and V) in environmental, biological and geological samples. Antimony may form various inorganic and organic compounds that exhibit differences in analytical behavior, toxicity and mobilityinorganic compounds of antimony are more toxic than organic forms and toxicity of Sb(III) has been shown to be 10 times higher than that of Sb(V). Therefore selective determination of Sb(III) and Sb(V) is required in environmental and biological samples. Hydride generation atomic absorption spectrometry is a sensitive, fast and economical technique for the determination of antimony at trace level. A possible non-chromatographic method for antimony speciation is hydride generation atomic absorption spectrometry that is based on the relatively slow kinetics of hydride formation from Sb(V). In this study, continuous flow hydride generation method for the determination of antimony was developed and hydride generation conditions were optimized. Analyte solution was prepared in 0.050 mol/L HCl and 1.2% (w/v) NaBH4 stabilized in 0.30% (w/v) NaOH was used as a reductant solution. Inorganic antimony speciation conditions were determined by continuous flow HGAAS system. For the pre-reduction of Sb(V) to Sb(III), 8.0% (w/v) potassium iodide (KI) and 0.10% (w/v) ascorbic acid were used. Further speciation study was also carried out using Ir coated W-coil Atom Trap Hydride Generation Atomic Absorption Spectrometry. Tungsten coil atom trap was used to enhance the sensitivity. Tungsten coil surface was treated with Ir and totally 250 &
#956
g 1000 mg/L Ir stock solution was used for coating of tungsten coil. LOD and LOQ values were calculated as 152 pg/mL and 508 pg/mL according to 120 seconds trapping. 128 and 37 fold enhancement were obtained for 120 seconds collection with respect to W-coil-ETAAS and ETAAS, respectively.
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Yildirim, Emrah. "Tellurium Speciation Using Hydride Generation Atomic Absorption Spectrometry And In-situ Graphite Cuvette Trapping." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610967/index.pdf.
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In recent years speciation analysis is becoming more important as it is known that each chemical form of an element behaves differently in biological and environmental media. Since abundance of tellurium in earth crust is extremely low, very sensitive and accurate methods are needed to determine the concentration of tellurium. Hydride generation atomic absorption is a sensitive, fast and economical technique applied for the determination of tellurium. Speciation of tellurium can be achieved by making use of different kinetic behaviors of Te(IV) and Te(VI) upon its reaction with sodiumborohydride.
A continuous flow hydride generation system was developed and parameters that affect the analytical signal were optimized. Sample solutions were prepared in 4.0 mol/L HClas reductant 0.5 % (w/v) sodiumborohydride in 0.5 % (w/v) NaOH was used. Quantitative reduction of Te(VI) was achieved through application of a microwave assisted prereduction of Te(VI) in 6.0 mol/L HCl solution. Sensitivity of the system was further enhanced by in-situ trapping of the formed H2Te species in a previously heated graphite furnace whose surface was modified using Pd or Ru. Overall efficiency of pyrolytic coated graphite surface was found to be 15% when hydrides are trapped for 60 seconds at 300 oC. LOD and LOQ values were calculated as 86 pg/mL and 287 pg/mL according to peak height values. Efficiency was increased by 46% and 36% when Pd and Ru modifiers were used, respectively. With Ru modified graphite tube 173 fold enhancement was obtained over 180 seconds trapping period with respect to direct ETAAS. LOD values were 6.4 and 2.2 pg/mL for Pd and Ru treated systems, respectively, for 180 s collection of 9.6 mL sample solution.
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True, James Bruce 1967. "Investigation of the use of charge-injection-device detectors for multielement atomic absorption spectrometry." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/282244.
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Graphite furnace atomic absorption spectrometry has excellent detection limits and accepts a wide variety of samples with little or no sample preparation. The method does, however, suffer from matrix interferences and a lack of highly capable multielement instrumentation. Continuum sources have been employed to GFAAS for multielement determinations, but the one dimensional array detectors used in these instruments can only observe a limited spectral range, limiting the multielement capabilities of these instruments. A continuum source, multielement graphite furnace atomic absorption spectrometer was developed here which employed a prototype echelle polychromator with charge injection device(CID) detection. The detection system employed a new device, the CID∼38, and camera control unit, the SCM5000E, with previously unavailable abilities. The camera system was developed and evaluated to determine its spectroscopic characteristics, and reprogrammed to provide rapid, continuous monitoring of many absorption signals simultaneously. A data acquisition and analysis scheme was developed for the prototype system, and the instrument demonstrated detection limits comparable to single-element line source GFAAS. The low ultraviolet throughput of the prototype echelle limited the spectral range that could be observed. Light scattering inside the spectrometer caused the sensitivity to decrease as the number of elements observed increased. A second echelle spectrometer system with higher wavelength resolution and increased throughput in the far ultraviolet was incorporated in to the instrument. The new system increased the spectral range which could be monitored, allowing more elements farther in the ultraviolet to be determined. The detection limits for the new system are comparable to single-element GFAAS, but degrade farther in the ultraviolet due largely to decreasing source output.
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Fellows, Craig Stephen. "Aluminium analysis in clinical samples by graphite furnace atomic absorption spectrometry and some fundamental studies of plasma source mass spectrometry." Thesis, University of Southampton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296427.
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Ozcan, Gurbetoglu Pelin Gulistan. "Determination Of Cadmium Using Slotted Quartz Tube Atom Trap Atomic Absorption Spectrometry And Metal Coatings." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612212/index.pdf.
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ABSTRACT
DETERMINATION OF CADMIUM USING SLOTTED QUARTZ TUBE ATOM TRAP ATOMIC ABSORPTION SPECTROMETRY AND METAL COATINGS
Özcan Gurbetoglu, G. Pelin M.S., Department of Chemistry Supervisor: Prof. Dr. O. Yavuz Ataman July 2010, 76 pages Flame atomic absorption spectroscopy (FAAS) is a common technique for detecting metals and metalloids in environmental, biological and metallurgical samples. Although it is a rather old technique, it is still very reliable, simple to use and inexpensive. The technique can be used to determine the concentration of over 70 different metals in a solution. However, it has detection limits at mg/L levels. Some atom trapping methods have been developed to reach the detection limits of ng/mL levels. Slotted quartz tube (SQT) is one of these atom trapping methods. It is an important technique, since it is easy to use, applicable in all laboratories, commercially available and economical. This thesis consists of development of a sensitive method for cadmium with the help of SQT atom trap. In this study, it was used for two different purposes. One was for keeping the analyte atoms more in the light path
in other words, for increasing the residence times of analyte atoms in the measurement zone. This first application was provided a 2.9 times enhancement with respect to conventional FAAS. Second application was for trapping the analyte on the surface of the SQT, in other words, for performing on-line preconcentration of cadmium in SQT. In the presence of a lean flame, analyte samples were trapped and collected for a few minutes at a low suction rate. After finishing the collection period, analyte atoms were revolatilized with the help of a small volume of (10-50 µ
L) methyl isobutyl ketone (MIBK) and a rapid atomization occurred. This introduction also altered the flame composition momentarily and analyte atoms were released from the surface of the SQT. Application of this method enhanced the sensitivity 2065 times with respect to conventional FAAS. Another approach to this type of atom trapping has been investigated also in this study, which was coating of SQT with some metals having low volatility. Therefore, some transition metals were coated to the surface of SQT and among them zirconium was selected as the best coating material as having the most sensitivity enhancement factor. That is why, rest of the study was performed with the Zr coated SQT. The enhancement was 3368 as compared with FAAS. Cd determination with this method provides LOD value of 8 pg/mL and Co value of 19 pg/mL. In order to see the effect of some other type of elements or ions on determination of cadmium, interference study was done.
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Karaman, Gamze. "Determination Of Silver By Slotted Quartz Tube Atom Trap Flame Atomic Absorption Spectrometry Using Metalcoatings." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613695/index.pdf.
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Silver is a precious metal having antibacterial property and widely used in industry mostly for water purification and medicinal products. Therefore, the determination of trace levels of silver is important for industrial applications. Flame atomic absorption spectrometry (FAAS) is a popular technique for the determination of relatively low concentration levels. This mature technique owes its widespread application to its simplicity and low cost. However, for some occasions, FAAS technique suffers from its low sensitivity because of low nebulization efficiency and relatively short residence time of analyte atoms in the measurement zone. In order to overcome this sensitivity problem, atom traps have been developed in recent years. Slotted quartz tube (SQT) is an accessory designed to use as an atom trap in conventional flame atomic absorption burner head. This thesis study involves the development of a sensitive, simple and economical technique with the help of the SQT for the determination silver. Firstly, the technique known as SQT-FAAS was used to increase the residence time of analyte atoms in the measurement zone. In this case, limit of detection (LOD) and characteristic concentration (C0) values were found to be 19 ng/mL and 35 ng/mL, respectively. Enhancement in sensitivity with respect to FAAS was found to be 2.31 fold using SQT-FAAS. Regarding the angle between the two slots of the SQT, 180°configuration was used. Secondly, in order to improve sensitivity further, the SQT was used as an atom trap (AT) where the analyte is accumulated in its inner wall prior to re-atomization. The signal is formed after reatomization of analyte atoms on the trap surface by introduction of organic solvent. For this purpose, uncoated SQT was used as a trap medium. However, there was a memory effect. Therefore, the SQT inner surface was coated with different coating elements and theoptimum conditions were found by using W-coated SQT-AT-FAAS technique. In the presence of a lean air-acetylene flame, analyte atoms were trapped in the inner surface of the SQT for 5.0 min and then revolatilized with the introduction of 25 &mu
L isobutyl methyl ketone (IBMK)
afterwards, a transient signal was obtained. These optimized parameters were used for uncoated SQT, W-coated SQT and Zr-coated SQT atom trap techniques. Sample suction rate was 6.25 mL/min in all techniques. Sensitivity was increased 54 fold using uncoated SQT-AT-FAAS technique with respect to simple FAAS technique. When W-coated SQT-AT-FAAS technique was applied, 135 fold sensitivity enhancement was obtained with respect to FAAS technique. The best sensitivity enhancement, 270 fold, was obtained using Zr-coated SQT-AT-FAAS technique. In addition, the Ag signals were more reproducible (%RSD, 1.21) when Zr was used as a coating element. After the sensitive technique was developed, interference effects of some transition and noble metals and hydride forming elements on Ag signals were investigated. Finally, surface studies were done to determine the chemical state of Ag during trapping period by using X-ray Photoelectron Spectroscopy (XPS). It was observed that the Ag analyte is retained on the SQT surface in its oxide form.
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Chen, Xi 1970. "Quasi-stable slurries for the determination of trace elements by graphite furnace atomic absorption spectrometry." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33386.
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High-pressure homogenization using a new flat valve homogenizer in combination with enzymatic digestion with a crude protease was investigated as a means of releasing Se compounds from zoological and botanical matrices prior to slurry introduction GF-AAS. Timed trials with four zoological certified reference materials (CRMs), three botanical reference materials (RMs), and a food crop indicated that Se release was quantitative after homogenization or became quantitative within 1 h of digestion at 60°C.The same technique was employed on five animal feed samples.
A new model of homogenizer equipped with ceramic homogenizing valve was evaluated in terms of analyte metal contamination levels within the final sample dispersion.
Five animal feed samples and four wood pulp samples, were investigated for their content of Cu, Fe and Mn using high-pressure homogenization as the sample preparation technique prior to GF-AAS. Dispersions of dried animal feeds were sub-sampled reliably after 7 days of storage at 4°C. Trials on pulp samples indicated that pulps could be sub-sampled reliably after 1 day of storage. (Abstract shortened by UMI.)
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JUNIOR, ANILTON COELHO COSTA. "DETERMINATION OF PLATINUM DERIVED FROM ANTI-CANCER DRUGS IN URINE SAMPLES BY ATOMIC ABSORPTION SPECTROMETRY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2007. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=11022@1.
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FUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DO RIO DE JANEIROFINANCIADORA DE ESTUDOS E PROJETOS
Devido à sua capacidade de inibição do processo de divisão celular, complexos de platina têm sido empregados na quimioterapia do câncer desde o final da década de 60, sendo a cisplatina e a carboplatina as formas mais utilizadas. Estudos farmacocinéticos e a estimativa da quantidade de platina acumulada no organismo durante o tratamento quimioterápico ou devido à exposição ao metal têm sido alvo de grande interesse. Logo, são necessários métodos analíticos adequados para o monitoramento de platina em amostras clínicas, apropriados para essas diferentes substâncias. No presente trabalho, foram desenvolvidos procedimentos analíticos rápidos, simples e exatos para determinação direta de platina, na forma de cisplatina e carboplatina, em urina humana, utilizando a espectrometria atômica. No caso da absorção atômica em forno de grafite, o programa de temperatura, o volume de amostra e a concentração do diluente (HNO3) foram definidos por um planejamento composto central. Nas condições otimizadas, os resultados obtidos pelo procedimento proposto não apresentaram diferenças estatisticamente significativas daqueles obtidos por procedimentos comparativos independentes, na análise de amostras de urina de paciente submetido ao tratamento com cisplatina. A calibração foi realizada por adição de analito, com PtCl2. Com a adição de NaCl ao meio diluente, os efeitos multiplicativos de matriz puderam ser contornados, permitindo a calibração externa com soluções de calibração preparadas no mesmo meio que o branco, utilizando sais inorgânicos de platina. Melhor sensibilidade também foi obtida, e recuperações de 98±4% foram observadas para os vários níveis de concentração estudados, assim como coeficientes de variação de 1 a 10%, tanto para a cis como para a carboplatina. O limite de detecção (n=10, k=3) foi de 4 (mi)g L-1 de Pt na amostra original. A espectrometria de absorção atômica com fonte contínua de alta resolução na chama (HR-CS F AAS) também foi estudada. As condições da chama foram definidas por um planejamento multivariado D-optimal, tomando-se como resposta a soma dos coeficientes angulares das curvas de adição de analito em três urinas diferentes, assim como o desvio padrão relativo dessas inclinações. O limite de detecção foi de 55 Og L-1 (n=10, k=3), na amostra original, em Pt, cerca de uma ordem de grandeza melhor do que aquele obtido utilizando-se um equipamento de fonte de linhas. Calibração externa, com soluções de calibração em urina livre de Pt, utilizando sal inorgânico de platina (PtCl2), foi possível, e os resultados obtidos por HR-CS F AAS não se mostraram significativamente diferentes daqueles encontrados por procedimentos comparativos independentes.
Platinum coordination compounds have been used in cancer chemotherapy since the late 1960s. Cisplatin and carboplatin are the most common platinum based drugs used in cancer treatment. Pharmacokinetics investigations, the determination of the body burden during the treatment as well as the baseline levels of platinum in humans has attracted great interest. Thus, accurate analytical methods for fast and easy platinum monitoring in clinical samples are necessary. In the present work, atomic spectrometric methods for the direct determination of platinum as cisplatin and carboplatin in human urine were investigated. In relation to Graphite Furnace Atomic Absorption Spectrometry the optimum temperature program, sample volume and diluent concentration were defined by a central composite design optimization. Analyte addition with PtCl2 was used for calibration, and no statistically significant difference was observed between the results obtained by the proposed and comparative procedures in the analysis of a set of urine samples. Multiplicative matrix effects were overcome by adding NaCl to the diluent solution. External calibration with PtCl2 in blank matched medium was then possible. The recoveries were 100±1%, and the coefficient of variation ranged from 1 to 10%. The limit of detection (LOD) was 4 ug L-1 of Pt in the original urine sample. High resolution continuous source flame atomic absorption spectrometry was also investigated. The flame conditions were optimized by a multivariate D-optimal design, taking as response the sum of the analyte addition calibration slopes and their standard deviation. The LOD was 55 Og L-1 (n=10, k=3), in the original sample. Matrix matched external calibration with PtCl2, was possible, and the results obtained by the proposed procedure were also in good agreement with those obtained by independent comparative procedures.
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曾令建 and Ling-kin Simon Tsang. "Graphite furnace capacitively coupled plasma atomic emission spectrometry in the determination of trace metals in biological andenvironmental samples." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31220009.
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Tsang, Ling-kin Simon. "Graphite furnace capacitively coupled plasma atomic emission spectrometry in the determination of trace metals in biological and environmental samples /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19737403.
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Carroll, J. H. "Development and application of probe atomisation in line-source and continuum-source electrothermal atomic absorption spectrometry." Thesis, University of Strathclyde, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382344.
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