Solid-phase microextraction (SPME) coupled with gas chromatography/mass spectrometry (GC/MS) is routinely used to analyze polycyclic aromatic hydrocarbons (PAHs) in water. A common SPME-GC/MS approach quantifies target analytes using isotopically labeled standards (IISs); one IIS is needed for each target analyte. This approach is challenging, even prohibitive since IISs are often expensive; moreover, they are generally not available for each analyte of interest. This study developed a novel SPME-GC/MS approach for the quantification of PAHs in water. The new method, which employs only a small number of IISs, uses relative response factor (RRF) (i.e., analyte corresponding to IIS) to quantify PAHs in water. Possible matrix dependency of RRFs values was examined using water that was modified concerning different physical-chemical characteristics (i.e., ionic strength, pH, suspended solids, humic acid, and biological organic carbon represented by hemoglobin). The results revealed that RRFs are not noticeably affected by changing ionic strength and pH; the other three parameters did affect the RRFs. However, the results also showed that the effect is minimal when the solution is dilute (i.e., low concentrations of suspended solids, humic acid or hemoglobin). Relatively stable RRFs for dilute water solutions indicates that this approach can be used for routine quantification of water that does not contain prohibitive amounts of suspended solids, humic acid, and biological organic matter. The developed method was employed to quantify trace levels of PAHs in three different types of water, namely river water, well water, and bottled water. PAH levels in every kind of water were less than 100 ng/L level (i.e., 0.1 ppb). Analyses of spiked water samples containing 2 ng PAHs revealed correlations between calculated RRFs and the physical-chemical properties of the PAHs investigated (i.e., vapor pressure, boiling point, octanol/water partition coefficient, octanol/air partition coefficient, GC retention time). This implies that RRFs for PAHs not examined in this study can be predicted. Overall, the results presented herein constitute a meaningful contribution to the development of SPME-GC/MS methods for quantitative analysis of PAHs and other chemicals in dilute aqueous solutions. Moreover, the development of methods that alleviate the need for IISs corresponding to each target analyte.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais / The present thesis demonstrates, for the first time, the possibility of using of the internal standard method in FIA or BIA systems with amperometric detection. The method allows to obtain accurate results in the presence of fluctuations in the system parameters (injected volume, dispensing rate, ionic strength and accidental insertion of air bubbles) and in the presence of contamination and/or gradual passivation of the working electrode surface. Methods for determination of diclofenac (DCF) using FIA with amperometric detection and simultaneous determination of DCF and codeine (CO) by BIA with amperometric detection have also been developed. The internal standard method was implemented in the flow injection analysis with multiple pulse amperometric detection (FIA-MPA) system by applying a sequence of potential pulses of the working electrode as a function of time. The analyte (+0.80 V/300ms) and internal standard (-0.05 V/400ms) were detected selectively, one at each potential pulse. Significant improvements were obtained in the accuracy of the system when the results before and after normalization (using the internal standard method), were compared. The following errors were calculated, respectively, before and after normalization of the results using the internal standard method. Change in flow rate from 3.0 to 1.0 ml min-1 (-57% e < 1%); volume injection from 300 to 100 &#956;L (-63% and 3%); ionic strength from 0.60 to 0.77 mol L-1 (-44 and 0,2%) and before and after the introduction of air bubbles into the system (-9,6% and 1,7%). A significant improvement was also obtained in the correlation coefficient of the calibration curve in the presence of problems of passivation or contamination of the working electrode. The correlation coefficient was calculated, respectively, as 0,975 and 0,998, before and after the normalization of the results by the IS method. The internal standard method was also applied to correct errors derived from the injection procedure (dispensing rate and injected volume) in batch injection analysis systems (BIA) with amperometric detection when disposable syringes were used. The results obtained before and after normalization of the results by the IS method were the following, respectively: repeatability test (RSD = 6.4 and 1.8%; n = 8), correlation coefficients (R=0.954 and 0.997) and errors obtained in analysis of synthetic samples (E = 9.4 ± 1.5 and 3.5 ± 0.7%; n = 8). The determination of DCF by FIA-MPA was implemented by applying two potential pulses to the BDD electrode using H2SO4 0.1 mol L-1 as supporting electrolyte: (i) + 1.2 V / 50 ms for oxidation and quantification of DCF, and (ii) 0.0 V / 50 ms for constant electrochemical cleaning of the electrode surface. The system showed good stability (RSD = 1.0%, n = 10) and high analytical frequency (135 injections h-1). The method showed a linear response between 5 and 50 &#956;mol L-1 and the detection and quantification limits were as 0.14 and 0.46 mmol L-1, respectively. The proposed method was applied to determine of DCF in pharmaceutical formulations and the obtained results were similar to those obtained by HPLC with a confidence level of 95%. The simultaneous determination of DCF and CO was performed using the following potential pulses: (i) +1.1 V / 50 ms: oxidation and quantification of DCF; (ii) +1.4 V / 50 ms: simultaneous oxidation of DCF and CO, (iii) 0.0 V / 200 ms: for constant electrochemical cleaning of the BDD electrode. The oxidation current from CO was obtained by the difference between currents detected at 1.4 and 1.1 V by using a correction factor. The system showed good stability (RSD = 0.9% and 1.1 for DCF and CO respectively, n = 10) and high analytical frequency (~ 300 injections h-1). The method showed a linear response between 10 and 50 &#956;mol L-1 for DCF and 7.1 and 35.7 &#956;mol L-1 for CO. The LQ and LD were calculated, respectively, at 1.1 and 3.7 &#956;mol L-1, for DCF and 1.0 and 3.3 mol L-1 for CO. The proposed method was applied for simultaneous determination of DCF and CO in pharmaceutical formulations and the obtained results were similar to those obtained by HPLC with a confidence level of 95%. Keywords: Multiple pulse amperometry, FIA, BIA, internal standard, simultaneous analysis, boron doped diamond (BDD), codeine, diclofenac. / Esta tese apresenta, pela primeira vez, a possibilidade de usar o método do padrão interno em sistemas FIA ou BIA com detecção amperométrica. O método permite a obtenção de resultados precisos na presença de flutuações em parâmetros dos sistemas (volume injetado, velocidade de injeção, força iônica e inserção acidental de bolhas de ar) e na presença de contaminação e/ou passivação gradual do eletrodo de trabalho. Métodos para determinação de diclofenaco (DCF) usando FIA com detecção amperométrica e simultânea de DCF e codeína (CO) por BIA com detecção amperométrica também foram desenvolvidos. O método do padrão interno foi implementado no sistema de análise por injeção em fluxo com detecção por amperometria de múltiplos pulsos (FIA-MPA) mediante a aplicação de uma sequência de pulsos de potenciais ao eletrodo de trabalho em função do tempo. O analito (+0,80 V/300ms) e o padrão interno (-0,05 V/400ms) foram detectados seletivamente, um em cada pulso de potencial. Melhoras significativas foram obtidas na precisão do método quando os resultados obtidos antes e após a normalização (usando o método do padrão interno) foram comparados. As seguintes variações foram calculadas, respectivamente, antes e após a normalização dos resultados usando o método do padrão interno. Variação na velocidade de vazão de 3,0 para 1,0 mL min-1 (-57% e < 1%); no volume de injeção de 300 para 100 &#956;L (-63% e 3%); força iônica de 0,60 para 0,77 mol L-1 (-44 e 0,2%) e antes e após a inserção de bolhas de ar no sistema (-9,6% e 1,7%). Uma melhora significativa também foi obtida no coeficiente de correlação da curva de calibração na presença de problemas de passivação ou contaminação do eletrodo de trabalho. O coeficiente de correlação foi calculado, respectivamente, em 0,975 e 0,998, antes e após a normalização dos resultados pelo método do PI. O método do padrão interno também foi aplicado para corrigir erros em sistemas de análise por injeção em batelada (BIA) com detecção amperométrica provenientes do procedimento de injeção (velocidade de injeção e volume injetado) quando seringas descartáveis foram utilizadas. Os resultados obtidos antes e após a normalização dos resultados pelo método do PI foram os seguintes, respectivamente: estudo de repetibilidade (DPR=6,4 e 1,8%; n = 8), coeficientes de correlação (R=0,954 e 0,997) e erros obtidos na análise de amostras sintéticas (9,4 ± 1,5% e 3,5 ± 0,7; n = 8). A determinação de DCF por FIA-MPA foi implementada através da aplicação de dois pulsos de potenciais ao eletrodo de BDD em meio de H2SO4 0,1 mol L-1 como eletrólito suporte: (i) +1,2 V / 50 ms para oxidação e quantificação do DCF e, (ii) 0,0 V / 50 ms para constante limpeza eletroquímica do eletrodo de trabalho. O sistema apresentou boa estabilidade (RSD = 1,0%; n=10) e elevada frequência analítica (135 injeções h-1). O método apresentou resposta linear entre 5 e 50 &#956;mol L-1 e os limites de detecção e quantificação foram calculados em 0,14 e 0,46 &#956;mol L-1, respectivamente. O método proposto foi aplicado na determinação de DCF em formulações farmacêuticas e os resultados obtidos foram similares ao obtidos por HPLC a um nível de confiança de 95%. A determinação simultânea de DCF e CO foi realizada usando os seguintes pulsos de potenciais: (i) +1,1 V / 50 ms: oxidação e quantificação de DCF; (ii) +1,4 V / 50 ms: para oxidação simultânea de DCF e CO; (iii) 0,0 V / 200 ms: para constante limpeza eletroquímica do eletrodo de BDD. A corrente de oxidação da CO foi obtida pela subtração entre as correntes detectadas em 1,4 e 1,1 V mediante uso de um fator de correção. O sistema apresentou boa estabilidade (RSD= 1,1 e 0,9% para DCF e CO, respectivamente, n=10) e elevada frequência analítica (~300 injeções h-1). O método apresentou resposta linear entre 10 e 50 &#956;mol L-1 para o DCF e entre 7,1 e 35,7 &#956;mol L-1 para CO. O LD e o LQ foram calculados, respectivamente, em 1,1 e 3,7 &#956;mol L-1, para DCF e 1,0 e 3,3 &#956;mol L-1 para CO. O método proposto foi aplicado na determinação simultânea de DCF e CO em formulações farmacêuticas e os resultados obtidos foram similares ao obtidos por HPLC a um nível de confiança de 95%. / Doutor em Química

O objetivo deste estudo foi avaliar parâmetros tais como, moagem, tamanho de partículas, homogeneidade, segregação, dissolução de amostras e amostragem de suspensão, visando o desenvolvimento de método para a determinação de Ir, Pd, Pt e Rh por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) em sílica mesoporosa para uso catalítico. Após a moagem em moinho eletrônico de almofariz e pistilo, a análise do tamanho e distribuição das partículas revelou que 89% das partículas apresentam tamanhos <100 &#181;m e 23% com tamanho <5 &#181;m. Na avaliação de segregação dos analitos na amostra, os resultados obtidos para amostra com moagem grosseira, indicaram que os elementos estão distribuídos de maneira heterogênea entre as frações. Entretanto, a moagem fina aumentou a homogeneidade e esta pode ser uma etapa importante e necessária no sentido de evitar segregação da amostra. A análise por difração e de Raios-X mostrou que não ocorreram reações mecanoquímicas durante a moagem e por fluorescência de Raios-X forneceu resultados discrepantes entre os laboratórios, o pode estar relacionado com a heterogeneidade que induziu erros de amostragem. A avaliação de desempenho do ICP OES foi feita a partir do estabelecimento de parâmetros de mérito como seletividade, repetibilidade, estabilidade, robutez e limite de detecção. Na otimização foram considerados os parâmetros potência, vazão de nebulização e vazão de gás auxiliar. Foi feito um estudo em solução aquosa e em meio da amostra para escolha das linhas de emissão dos elementos Ir, Pd, Pt, Rh e dos candidatos a padrões internos. Apesar dos bons resultados encontrados em solução aquosa, o aumento do sinal de fundo em meio da amostra restringiu a escolha dos comprimentos de onda. Para o estudo da dissolução das amostras foram avaliados quatro procedimentos em forno de micro-ondas com frasco fechado. Os melhores resultados foram obtidos com 150 mg de amostra, 6 mL de água régia e 210 ºC de aquecimento durante 60 min. As determinações por ICP OES usando padrões internos Ru para Pd, Yb para Pt e Dy para Rh foram aquelas que forneceram os resultados mais coerentes com aqueles obtidos por fluorescência de Raios-X. Nos estudos visando à introdução de amostra na forma de suspensão foram avaliados: a massa de amostra para o preparo da suspensão, o efeito da concentração de ácido nítrico e o uso de padrão interno na tentativa de corrigir erros de matriz. 60 mg de amostra com um volume final de 20 mL de ácido nítrico 0,5% (v v-1) foram os escolhidos. Entretanto, a determinação dos elementos via suspensão mostrou resultados muito inferiores aos valores de concentrações esperados. Irídio foi investigado somente para otimização de ICP OES porque a sílica mesoporosa para uso de catalisador automotivo tem não esse elemento em sua composição. / The aim of this study was to evaluate parameters such as grinding, particle size, homogeneity, segregation, sample dissolution and slurry sampling for method development for the determination of Ir, Pd, Pt and Rh in silica mesoporosa for catalyst using inductively coupled plasma optical emission spectrometry (ICP OES). After the grind in an electronic grider with mill and pistil, the analysis of the particle size distribution showed 89% of particles with sizes <100 &#181;m and 23% of particles with sizes <5&#181;m. The separation in different particle size fractions showed that the sample with coarse grind (as sent to the lab) is not homogenous for the elements in comparison with that submitted to grind. X-Ray Diffraction and X-Ray Fluorescence analysis did not showed chemical reactions during the grinding, however a discrepancy between results of different laboratories. The performance of ICP OES was made by using figures of merit such as selectivity, repeatability, stability, robustness and limit of detection. In the optimization of ICP OES power supply, nebulizer flow rate and auxiliary gas flow rate were considered. Studies were conducted in aqueous and in the sample solution to choose emission wavelengths for Ir, Pd, Pt, Rh and internal standard candidates. Despite the good results obtained in aqueous solution, increasing the background signal in sample media restricted the choice of the emission wavelengths. For sample dissolution four procedures using microwave oven with closed-vessel were evaluated. The best results were obtained with 150 mg of the sample, 6 mL of aqua-regia and 210 ºC of heating, during 60 min. Determinations by ICP OES using internal standards Ru for Pd, Yb for Pt, and Dy for Rh were those who provided more consistent results in comparison with those obtained by x-ray fluorescence. For slurry sampling introduction sush parameters were evaluated: the mass of sample to prepare the slurry, the effect of the nitric acid concentration and the use of internal standard to correct matrix effects. 60 mg of the sample with a final volume of 20 mL of nitric acid 0.5% (v v-1) were chosen. However, the determination of Pd, Pt and Rh via suspension showed concentrations below to those expected, as determined by ICP OES in solution. Iridium was investigated only for ICP OES optimization because the silica mesoporosa for automobile catalyst use have not this element in its composition.

Das übergeordnete Ziel dieser Promotion war die Untersuchung und Kompensation des Matrixeffekts für die Analytik von Arzneimitteln in komplexen Probenmatrices mit LC-ESI-MS/MS-Technik. Zunächst konnte eine einfache analytische Methode für eine breite analytische Anwendbarkeit entwickelt werden. Es zeigte sich jedoch, dass die Matrixeffektkompensation zu einem Mehraufwand bei der Probenvorbereitung führt. Deshalb wurde anschließend der Mechanismus des Matrixeffektes auf die LC-ESI-MS/MS-Technik genauer untersucht. Die gewonnenen Erkenntnisse wurden anschließend eingesetzt, um eine einfache alternative Quantifizierungsmethode mittels der PCI eines internen Standards zu entwickeln. Im ersten Teilprojekt wurde eine LC-ESI-MS/MS-Methode für die Analytik von häufig verschriebenen Antibiotika in Abwasserproben der Stadt Dresden entwickelt. Da weder Vergleichsmatrix für Abwasser zur Verfügung stand, noch für alle Zielanalyte isotopenmarkierte Standards erhältlich sind, wurde der stark variierende Matrixeffekt der Abwasserproben mittels der Standardaddition kompensiert. Die Ergebnisse der Methodenentwicklung zeigen, dass eine genaue und flexible Methode entwickelt werden konnte, die Matrixkompensation jedoch zu einem erhöhten Zeit- und Materialaufwand führt. Es wurde deutlich, dass neben bisher genutzten Kompensationsmethoden für den Matrixeffekt, wie Standardaddition und interner isotopenmarkierter Standards, neue alternative Strategien getestet werden müssen. In dem zweiten Teilprojekt wurde daher der Matrixeffektmechanismus von Urin-, Plasma- und verschiedenen Abwasserproben bei der Messung von verschiedenen Arzneimitteln mittels LC-ESI-MS/MS analysiert. Die Ergebnisse der Untersuchungen mittels „post-column infusion“ konnten bisherige Erkenntnisse zu Matrixeffektmechanismen bestätigen und das Verständnis vertiefen. Matrixeffekte sind von der jeweiligen Zusammensetzung der Probenmatrix abhängig, aber auch substanzspezifisch. Dabei kommt es zwischen Analyt und Begleitsubstanzen zu einer Konkurrenz um freie Ladungsträger oder zu einer veränderten Anordnung/Verteilung innerhalb der ESI-Spray-Tröpfchen. Gleichzeitig zeigten die Ergebnisse, dass es auch andere Mechanismen, wie z. B. Ladungstransfers zwischen Analyt und Begleitsubstanzen, geben muss. Schließlich wurden die Ergebnisse des zweiten Teilprojekts in einer innovativen Methodenentwicklung zur Matrixkompensation und zur Quantifizierung von 16 Arzneimitteln in Urinproben verwendet. Der Matrixeffekt der Substanzen mit vergleichbarer Signalsuppression konnte über einen einzelnen nachsäuleninfundierten internen Standard kompensiert werden. Die Ergebnisse zeigen einen deutlichen Vorteil der entwickelten Methode gegenüber Matrix-Kalibrierung in Präzision und Richtigkeit oder dem Einsatz von isotopenmarkierten internen Standards in Aufwand der Methodenentwicklung und Verbrauch von Standardsubstanzen. Die Ergebnisse der vorliegenden Arbeit zeigen die Bedeutung, Komplexität und den Einfluss der Matrixeffekte in der Anwendung der LC-ESI-MS/MS-Technik. Einerseits sind geeignete Methoden für die Minimierung von Matrixeffekten wie Probenvorbereitung und Chromatographie nötig, andererseits müssen Ionisierungsmechanismen, insbesondere die Wechselwirkungen von Zielanalyten und Begleitsubstanzen, zukünftig Gegenstand weiterer Untersuchungen sein. Die Ergebnisse dieser Arbeit liefern wichtige Beiträge zur Verbesserung der Analytik von komplexen Proben mittels der LC-ESI-MS/MS-Technik. / The overall goal of this Ph.D. thesis was to investigate and compensate the matrix effect of the analysis of drugs in complex sample matrices with LC-ESI-MS/MS technique. First, a simple analytical method for a broad analytical applicability was developed for wastewater analysis. However, the matrix effect compensation embraced the main part effort in sample preparation. Therefore, the mechanism of the matrix effect on the LC-ESI-MS/MS technique was examined in more detail. The findings were used to develop an alternative quantification method using post-column infusion of an internal standard substance. In the first project, a LC-ESI-MS/MS method was developed to analyze commonly prescribed antibiotics in wastewater samples of Dresden. Since neither comparison matrix for wastewater nor all isotopically-labeled analogs for the target analytes were available, the strongly varying matrix effect of the wastewater samples was compensated by standard addition. The results show that the developed method is precise and flexible, but the matrix effect compensation leads to an increased expenditure of time and materials. Besides previously used matrix effect compensation methods, such as standard addition and internal isotopically-labeled standard, new alternative strategies need to be tested. Therefore, the matrix effect mechanism of various drugs and sample matrix combinations was examined in the second project using post-column infusion. The results confirmed previous findings on matrix effect mechanisms and deepened our understanding that matrix effects not only depend on the composition of the sample matrix but are also substance-specific. This results to a competition of free charge carriers between analyte and accompanying substances or to an alternated distribution within the ESI spray droplets. Furthermore, the results indicate that there are other mechanisms, such as charge transfer between analyte and concomitant substances. The results of the second project were used to invent a method for matrix effect compensation and quantification of 16 drugs in urine samples. The matrix effects of the substances with comparable signal suppression were compensated by a single post-column infused internal standard. The developed method has a significant advantage over the matrix calibration regarding precision and accuracy as well as the use of isotopically-labeled internal standards in effort of method development and consumption of standard substances. Finally, the results of this work show the importance, complexity and influence of the matrix effects in the application of the LC-ESI-MS/MS-technique. Suitable methods for minimizing matrix effects such as sample preparation and chromatography are needed and ionization mechanisms, in particular the interactions of target analytes with accompanying substances, should be investigated in future studies. The work of this Ph.D. project contributes to the improvement of the analysis of complex samples using the LC-ESI-MS/MS-technique.

Desde a prospecção do minério bauxita, passando pelo seu beneficiamento até a sua entrada no processo Bayer, tem-se como principais índices de qualidade e de processo os parâmetros químicos: alumina aproveitável (Al2O3Ap) e sílica reativa (SiO2Re), determinados segundo um procedimento que simula a digestão Bayer em escala de laboratório. Uma grande inovação para a indústria da bauxita seria fazer o controle por parâmetros mineralógicos, % gibbsita e % caulinita, via difratometria de raios X, intenção buscada nesse trabalho pela proposta de um método combinado Rietveld-Le Bail-Padrão Interno, cujos resultados são bem promissores para bauxitas gibbsíticas tipo-Paragominas, matriz para qual foi desenvolvido. Tal combinação não só melhorou a qualidade da quantificação de gibbsita e caulinita, como diminuiu o peso de cálculo tornando o procedimento mais prático e rápido. A alta correlação (r2=0,99) entre os resultados mineralógicos pelo método combinado e os resultados químicos pelo método tradicional, os deixam em igual escolha, pois foram iguais estatisticamente. No entanto, ressalta-se que o método tradicional subestima o valor de caulinita pela conversão da SiO2Re, enquanto o método combinado se aproxima mais do valor verdadeiro. Obter um resultado pelo método combinado mostrou ser mais prático e rápido que pelo método tradicional. Enquanto o tempo total estimado pelo combinado é < 3 h, pelo tradicional é de no mínimo 6 h. Como proposta de validação do método combinado, um segundo foi desenvolvido para quantificação de Al-goethita por DSC, o qual mostrou boa precisão. E muito embora o uso da técnica no controle industrial seja pouco provável por questões de praticidade e tempo de análise, usá-la na validação de antigos e novos métodos de quantificação mineralógica de bauxitas pode ser muito útil. A ordem crescente de substituição de Fe por Al pretendida pelas sínteses planejadas (7 variedades) foi confirmada pelos resultados de DRX, FRX, DSC e MEV, e assim um pequeno banco de dados de entalpias padrão de desidroxilação de Al-goethitas foi estabelecido. A produção de padrões complexos, misturas de variedades goethíticas, é tão importante quanto produzir uma só goethita, pois tais misturas são termodinamicamente comuns na natureza e, portanto, comuns em bauxitas. Após uma identificação clara da limitação do método tradicional para estimar caulinita pela conversão de SiO2Re em bauxitas tipo-Paragominas, um estudo de otimização do método Alcan foi realizado com base em um planejamento fatorial completo 23. As variáveis escolhidas foram temperatura, concentração cáustica e tempo para duas situações: bauxita com baixa SiO2Re e bauxita com alta SiO2Re. A temperatura foi a variável mais importante, apresentando um efeito positivo sobre a quantidade de SiO2Re, uma vez que o aumento na temperatura aumentou a taxa de conversão completa de caulinita em sodalita. Modelos empíricos de 1ª ordem foram apropriadamente obtidos para predição da quantidade de SiO2Re como função da temperatura, concentração cáustica e tempo, os quais responderam com as seguintes condições ótimas: (1) sem presença significante de quartzo - temperatura de 180 °C, concentração cáustica de 10 % com tempo de 60 min para baixa SiO2Re e 25 min para alta SiO2Re, e (2) com presença significante de quartzo - temperatura de 150 °C, concentração cáustica de 20 % e tempo de 60 min, para ambas as situações estudadas. / In the bauxite industry - exploration, beneficiation and refinery - two main chemical parameters are used for the quality control: available alumina (AvAl2O3) and reactive silica (RxSiO2). They are determined by a procedure that simulates the Bayer process in laboratory scale. A great innovation for this industry would be to make this control by mineralogical parameters, i.e., the % of gibbsite and % of kaolinite via Powder X-ray Diffraction Analysis. This is one of the main purposes of this work by means of a combined Rietveld-Le Bail-Internal Standard Method, whose results were very promising for the Paragominas-type bauxites. This combination not only improved the quality of gibbsite and kaolinite quantification, as decreased computer processing time, making it a more convenient and fast procedure. The high correlation (r2=0.99) between the mineralogical results from the combined method and chemical results by the traditional method, leave them the same choice, as they were statistically equal. However, it is noteworthy that the traditional method underestimates the kaolinite value obtained from the conversion of RxSiO2, while the combined method is closer to the true value. Obtaining a result by the combined method proved to be more convenient and faster (< 3 hours) than the traditional method (at least 6 hours). As a validation for the proposed combined method, a second method was developed to quantify Al-goethite by DSC, which showed good accuracy. Although the use of DSC technique in industrial control is unlikely for practical reasons and analysis time, its use can be very helpful in the validation of old and new methods for the mineralogical quantification of bauxites. XRD, XRF, DSC and SEM results confirmed the increasing order of Al for Fe replacement intended for the planned synthesis (7 types). Thus, a small database of standard enthalpies of Al-goethites dehydroxylation was built. The production of standards of goethites mixtures is as important as producing a single goethite standard, because these are thermodynamically common in nature and thus bauxites with complex mixtures of goethites are also common. After clearly identifying the limitations of the traditional method to estimate kaolinite from the conversion of RxSiO2 in the Paragominas-type bauxites, an optimization study of the Alcan method was carried out based on a 23 full factorial design. The chosen variables were temperature, caustic concentration and time, for two main situations: bauxite with low RxSiO2 and bauxite with high RxSiO2. The temperature was the most important variable, with a positive effect on the amount of RxSiO2, since the increase in temperature increased the rate of full kaolinite to sodalite conversion. First-order empirical models were properly obtained to predict the amount of RxSiO2 as a function of temperature, caustic concentration and time, which responded to the following optimal conditions: (1) without significant amount of quartz - 180 °C, NaOH 10 % and 60 min for low RxSiO2 and 25 min for high SiO2Re, and (2) with significant amount of quartz - 150 °C, NaOH 20 % and 60 min for both situations.

This thesis describes two different sample preparation strategies for inductively coupled plasma atomic emission spectrometry (ICP-AES), and their ability regarding multi element quantification in complex samples. Sensitivity, repeatability, reproducibility and accuracy were investigated. The aim was to increase the over all efficiency, the speed of analysis, and/or the sensitivity of the analytical method. The intention was to measure analytes with concentrations ranging from ng/g to mg/g simultaneously. The aim was additionally to study chemical and physical processes occurring during the sample preparation, the sample transport to the plasma, and the atomization therein. In the first sample preparation strategy, a hydrophilic highly cross-linked iminodiacetate-agarose adsorbent, IDA-Novarose, was used for preconcentration of metal ions, and matrix elimination in natural water samples. The sorbent was synthesized with different binding capacities. The effect of the capacity on preconcentration, matrix elimination, and uptake capability at high flow rates was studied. For a high capacity IDA-Novarose (≥ 45 µmole/ml) quantitative uptake was seen even at high flow rates (100 ml/min) for Cu2+ with a high affinity to the adsorbent, and for Cd2+ with a moderate affinity. For lower capacities the uptake of Cd2+ was affected by the sample matrix and the flow rate. A method based on the determination of the conditional stability constant of the metal sorbent complex was suggested for the prediction of the sorbent capacity needed to obtain quantitative recovery and optimal matrix elimination. The sorbent was used in a flow system with online buffering for the analysis of a certified riverine water (SLRS-3), tap water and lake water. With few exceptions the results obtained by ICP-AES after preconcentration agreed well with the certified concentrations and results obtained by ICP-MS. The other sample preparation strategy discussed is a method for non digested biological samples from different animal organs for the multi element analysis by ICP-AES. This “mix and measure method” consists of a simple homogenization of the sample with a mixing rod in a small amount of neutral media, followed by dilution and direct measurement with ICP-AES. The total time of analysis is only a few minutes. The ability of this fast method to accurately quantify some elements of toxic, environmental, and/or physiological concern with the lowest possible sample dilution and the highest possible plasma load was evaluated. In 10 % liver slurry Cd, Co, and Sr, at concentration levels around 0.05 µg/g were quantified simultaneously with P and K around 2000 µg/g and with several other elements in between (Al, Ca, Cu, Fe, Mg, Mn, Pb, and Zn). The relative standard deviation of repeated measurements of samples was around 5 - 6 % for regardless of the concentration of the element. The method was also used for fast screening of the elemental distribution in mice organs (brain, heart, kidney, liver, lung and spleen).

Desde a prospecção do minério bauxita, passando pelo seu beneficiamento até a sua entrada no processo Bayer, tem-se como principais índices de qualidade e de processo os parâmetros químicos: alumina aproveitável (Al2O3Ap) e sílica reativa (SiO2Re), determinados segundo um procedimento que simula a digestão Bayer em escala de laboratório. Uma grande inovação para a indústria da bauxita seria fazer o controle por parâmetros mineralógicos, % gibbsita e % caulinita, via difratometria de raios X, intenção buscada nesse trabalho pela proposta de um método combinado Rietveld-Le Bail-Padrão Interno, cujos resultados são bem promissores para bauxitas gibbsíticas tipo-Paragominas, matriz para qual foi desenvolvido. Tal combinação não só melhorou a qualidade da quantificação de gibbsita e caulinita, como diminuiu o peso de cálculo tornando o procedimento mais prático e rápido. A alta correlação (r2=0,99) entre os resultados mineralógicos pelo método combinado e os resultados químicos pelo método tradicional, os deixam em igual escolha, pois foram iguais estatisticamente. No entanto, ressalta-se que o método tradicional subestima o valor de caulinita pela conversão da SiO2Re, enquanto o método combinado se aproxima mais do valor verdadeiro. Obter um resultado pelo método combinado mostrou ser mais prático e rápido que pelo método tradicional. Enquanto o tempo total estimado pelo combinado é < 3 h, pelo tradicional é de no mínimo 6 h. Como proposta de validação do método combinado, um segundo foi desenvolvido para quantificação de Al-goethita por DSC, o qual mostrou boa precisão. E muito embora o uso da técnica no controle industrial seja pouco provável por questões de praticidade e tempo de análise, usá-la na validação de antigos e novos métodos de quantificação mineralógica de bauxitas pode ser muito útil. A ordem crescente de substituição de Fe por Al pretendida pelas sínteses planejadas (7 variedades) foi confirmada pelos resultados de DRX, FRX, DSC e MEV, e assim um pequeno banco de dados de entalpias padrão de desidroxilação de Al-goethitas foi estabelecido. A produção de padrões complexos, misturas de variedades goethíticas, é tão importante quanto produzir uma só goethita, pois tais misturas são termodinamicamente comuns na natureza e, portanto, comuns em bauxitas. Após uma identificação clara da limitação do método tradicional para estimar caulinita pela conversão de SiO2Re em bauxitas tipo-Paragominas, um estudo de otimização do método Alcan foi realizado com base em um planejamento fatorial completo 23. As variáveis escolhidas foram temperatura, concentração cáustica e tempo para duas situações: bauxita com baixa SiO2Re e bauxita com alta SiO2Re. A temperatura foi a variável mais importante, apresentando um efeito positivo sobre a quantidade de SiO2Re, uma vez que o aumento na temperatura aumentou a taxa de conversão completa de caulinita em sodalita. Modelos empíricos de 1ª ordem foram apropriadamente obtidos para predição da quantidade de SiO2Re como função da temperatura, concentração cáustica e tempo, os quais responderam com as seguintes condições ótimas: (1) sem presença significante de quartzo - temperatura de 180 °C, concentração cáustica de 10 % com tempo de 60 min para baixa SiO2Re e 25 min para alta SiO2Re, e (2) com presença significante de quartzo - temperatura de 150 °C, concentração cáustica de 20 % e tempo de 60 min, para ambas as situações estudadas. / In the bauxite industry - exploration, beneficiation and refinery - two main chemical parameters are used for the quality control: available alumina (AvAl2O3) and reactive silica (RxSiO2). They are determined by a procedure that simulates the Bayer process in laboratory scale. A great innovation for this industry would be to make this control by mineralogical parameters, i.e., the % of gibbsite and % of kaolinite via Powder X-ray Diffraction Analysis. This is one of the main purposes of this work by means of a combined Rietveld-Le Bail-Internal Standard Method, whose results were very promising for the Paragominas-type bauxites. This combination not only improved the quality of gibbsite and kaolinite quantification, as decreased computer processing time, making it a more convenient and fast procedure. The high correlation (r2=0.99) between the mineralogical results from the combined method and chemical results by the traditional method, leave them the same choice, as they were statistically equal. However, it is noteworthy that the traditional method underestimates the kaolinite value obtained from the conversion of RxSiO2, while the combined method is closer to the true value. Obtaining a result by the combined method proved to be more convenient and faster (< 3 hours) than the traditional method (at least 6 hours). As a validation for the proposed combined method, a second method was developed to quantify Al-goethite by DSC, which showed good accuracy. Although the use of DSC technique in industrial control is unlikely for practical reasons and analysis time, its use can be very helpful in the validation of old and new methods for the mineralogical quantification of bauxites. XRD, XRF, DSC and SEM results confirmed the increasing order of Al for Fe replacement intended for the planned synthesis (7 types). Thus, a small database of standard enthalpies of Al-goethites dehydroxylation was built. The production of standards of goethites mixtures is as important as producing a single goethite standard, because these are thermodynamically common in nature and thus bauxites with complex mixtures of goethites are also common. After clearly identifying the limitations of the traditional method to estimate kaolinite from the conversion of RxSiO2 in the Paragominas-type bauxites, an optimization study of the Alcan method was carried out based on a 23 full factorial design. The chosen variables were temperature, caustic concentration and time, for two main situations: bauxite with low RxSiO2 and bauxite with high RxSiO2. The temperature was the most important variable, with a positive effect on the amount of RxSiO2, since the increase in temperature increased the rate of full kaolinite to sodalite conversion. First-order empirical models were properly obtained to predict the amount of RxSiO2 as a function of temperature, caustic concentration and time, which responded to the following optimal conditions: (1) without significant amount of quartz - 180 °C, NaOH 10 % and 60 min for low RxSiO2 and 25 min for high SiO2Re, and (2) with significant amount of quartz - 150 °C, NaOH 20 % and 60 min for both situations.

The aim of this paper is to document the development of a method for detectionand quantification of Polychlorinated biphenyls (PCB) in soil using GasChromatography (GC) connected to a Quadrupole Mass Spectrometer (MS) via aninternal standard (CB189). The method developed is performed in conjunction withthe information provided by the Swedish environmental agency (Svenskanaturvårdsverket, SNV) in regards to PCB limits for sensitive land usage. The steps ofthe method and maintenance of the GC/MS are used to create a user manual andan attempt at transformative learning is done in an effort to teach the staff atLjungaLab AB so that at the very least, independent analysis can be run and at best,new methods and application are independently developed for the GC/MS. Anevaluation of the teaching efforts is also done to assess what grade of learning isachieved. / Syftet med denna uppsats är att dokumentera utvecklingen av en metod fördetektion och kvantifiering av polyklorerade bifenyler (PCB) i jord med hjälp avgaskromatografi (GC) ansluten till en masspektrometer (MS) och med användningav en intern standard (CB189). Metoden som utvecklats skapades med hjälp avuppgifter från det svenska naturvårdsverket (SNV) angående PCB-gränser för känsligmarkanvändning. Därefter skapades en användarmanual som beskriver stegen imetoden och även underhåll av GC/MS. Personalen på LjungaLab AB undervisadesi hur man använder och underhåller instrumenten för att, åtminstone, kunna köraoberoende analyser, och i bästa fall, utveckla nya metoder och tillämpningarsjälvständigt. Det sistnämda är ett försök till transformativ lärande. En utvärdering avlärarinsatser sker också för att bedöma vilken grad av lärande som uppnås.

Le cholestérol est l'une des molécules biologiques indispensable au bon fonctionnement de la plupart des organismes vivants, y compris chez l’homme. Cette molécule se trouve en abondance dans des tissus cérébraux et joue trois rôles principaux dans l'organisme. C’est un constituant (composant) essentiel de la membrane cellulaire qui sert à maintenir l’intégrité et la fluidité des cellules. Le cholestérol est aussi un élément déclencheur pour la production d’hormones stéroïdiennes comme les hormones sexuelles et la vitamine D. Finalement, il contribue à la production des acides biliaires par le foie. Dans cette étude, une méthode analytique de quantification absolu du cholestérol dans sections tissulaires de cerveau de souris par IMS a été développée. Pour ce faire, dans un premier temps des courbes d’étalonnage faites à partir de concentrations croissantes de cholesterol-d7 ont été réalisé en dopant directement des sections minces d’homogénat de cerveau. Par la suite, un étalon interne de stigmastérol (un stérol naturel d’origine exclusivement végétale) a été utilisé pour normaliser les signaux en provenance du cholestérol et du cholestérol-d7. Finalement, les analyses ont été effectué en utilisant une méthode IMS préalablement développée au laboratoire pour la détection spécifique et l’imagerie du cholestérol par désorption ionisation laser assistée par l’argent. L’étalon interne a été utilisé ici pour réduire les erreurs instrumentales, et les résultats avant et après normalisation montrent le rôle fonctionnel de cette méthode dans l’amélioration de la linéarité de la courbe d’étalonnage et, en conséquence, la mesure précise du cholestérol dans des échantillons analysés. / Cholesterol is one of the biological molecules essential for the proper functioning of most living organisms, including humans, and accurate quantification of cholesterol has many potential implications. This molecule is found abundantly in the brain and plays three main roles in the body. It is an essential component of the cell membrane which serves to maintain the integrity and fluidity of cells. Cholesterol is also a chemical trigger for the production of various steroid hormones such as sex hormones and vitamin D. Ultimately, it helps the liver to produce bile acids. A greater understanding of cholesterol and of its role in the body may directly impact our understanding of these processes. In this study, an analytical method for the absolute quantification of cholesterol in the mouse brain slices by IMS was developed. To achieve this calibration curves made from increasing concentrations of cholesterol-d7 were first performed by doping them on thin sections of brain homogenate. Subsequently, stigmasterol (a natural sterol of exclusively plant origin) was used as an internal standard to normalize the signals from cholesterol and cholesterol-d7 was evenly deposited over all analyzed sections. Finally, the analyzes were performed using an IMS method previously developed in the laboratory for the specific detection and imaging of cholesterol by silver-assisted laser ionization desorption. The internal standard was used here to reduce instrument errors, and the before and after normalization results show the functional role of this method in improving the linearity of the calibration curve and, therefore, the accurate measurement of cholesterol in the analyzed samples.