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Investigation Of Extraction Methodologies For Quantitative Determination Of Polycyclic Aromatic Hydrocarbons In SedimentsTopal, Tansel 01 January 2011 (has links) (PDF)
The extraction procedures for the determination of polycyclic aromatic hydrocarbons (PAH) concentrations in sediment samples had been developed by using GC-FID and GC-MS. The optimized methods were soxhlet extraction, ultrasonic bath extraction and solid phase micro extraction (SPME). In order to search out the main factors affecting extraction efficiencies of the methods, factorial design was used. The best extraction method was chosen and optimum values for main factors were selected for the development of the extraction method for PAH determination in sediment samples. The accuracy of the method was verified by analyzing NIST SRM 1597 (complex mixture of polycyclic aromatic hydrocarbons from coal tar). The selectivitiy and sensitivity obtained were quite adequate for the determination of PAHs in sediment sample. The best extraction and analysis methods were then applied to determine 16 PAHs in sea sediments from Ö / lü / deniz Lagoon, Mugla, Turkey and 19 PAHs in Ikizcetepeler Dam Lake, Balikesir, Turkey sediments to illustrate the capability of the selected extraction and analysis method to detect PAHs and to determine the status of the contamination.
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Infrared spectroscopy and advanced spectral data analyses to better describe sorption of pesticides in soils.Forouzangohar, Mohsen January 2009 (has links)
The fate and behaviour of hydrophobic organic compounds (e.g. pesticides) in soils are largely controlled by sorption processes. Recent findings suggest that the chemical properties of soil organic carbon (OC) significantly control the extent of sorption of such compounds in soil systems. However, currently there is no practical tool to integrate the effects of OC chemistry into sorption predictions. Therefore, the K [subscript]oc model, which relies on the soil OC content (foc), is used for predicting soil sorption coefficients (K[subscript]d) of pesticides. The K[subscript]oc model can be expressed as K[subscript]d = K[subscript]oc × foc, where K[subscript]oc is the OC-normalized sorption coefficient for the compound. Hence, there is a need for a prediction tool that can effectively capture the role of both the chemical structural variation of OC as well as foc in the prediction approach. Infrared (IR) spectroscopy offers a potential alternative to the K[subscript]oc approach because IR spectra contain information on the amount and nature of both organic and mineral soil components. The potential of mid-infrared (MIR) spectroscopy for predicting K[subscript]d values of a moderately hydrophobic pesticide, diuron, was investigated. A calibration set of 101 surface soils from South Australia was characterized for reference sorption data (K[subscript]d and K[subscript]oc) and foc as well as IR spectra. Partial least squares (PLS) regression was employed to harness the apparent complexity of IR spectra by reducing the dimensionality of the data. The MIR-PLS model was developed and validated by dividing the initial data set into corresponding calibration and validation sets. The developed model showed promising performance in predicting K[subscript]d values for diuron and proved to be a more efficacious than the K[subscript]oc model. The significant statistical superiority of the MIR-PLS model over the K[subscript]oc model was caused by some calcareous soils which were outliers for the K[subscript]oc model. Apart from these samples, the performance of the two compared models was essentially similar. The existence of carbonate peaks in the MIR-PLS loadings of the MIR based model suggested that carbonate minerals may interfere or affect the sorption. This requires further investigation. Some other concurrent studies suggested excellent quality of prediction of soil properties by NIR spectroscopy when applied to homogenous samples. Next, therefore, the performance of visible near-infrared (VNIR) and MIR spectroscopy was thoroughly compared for predicting both foc and diuron K[subscript]d values in soils. Some eleven calcareous soils were added to the initial calibration set for an attempt to further investigate the effect of carbonate minerals on sorption. MIR spectroscopy was clearly a more accurate predictor of foc and K[subscript]d in soils than VNIR spectroscopy. Close inspection of spectra showed that MIR spectra contain more relevant and straightforward information regarding the chemistry of OC and minerals than VNIR and thus useful in modelling sorption and OC content. Moreover, MIR spectroscopy provided a better (though still not great) estimation of sorption in calcareous soils than either VNIR spectroscopy or the K[subscript]oc model. Separate research is recommended to fully explore the unusual sorption behaviour of diuron in calcareous soils. In the last experiment, two dimensional (2D) nuclear magnetic resonance/infrared heterospectral correlation analyses revealed that MIR spectra contain specific and clear signals related to most of the major NMR-derived carbon types whereas NIR spectra contain only a few broad and overlapped peaks weakly associated with aliphatic carbons. 2D heterospectral correlation analysis facilitated accurate band assignments in the MIR and NIR spectra to the NMR-derived carbon types in isolated SOM. In conclusion, the greatest advantage of the MIR-PLS model is the direct estimation of Kd based on integrated properties of organic and mineral components. In addition, MIR spectroscopy is being used increasingly in predicting various soil properties including foc, and therefore, its simultaneous use for K[subscript]d estimation is a resource-effective and attractive practice. Moreover, it has the advantage of being fast and inexpensive with a high repeatability, and unlike the K[subscript]oc approach, MIR-PLS shows a better potential for extrapolating applications in data-poor regions. Where available, MIR spectroscopy is highly recommended over NIR spectroscopy. 2D correlation spectroscopy showed promising potential for providing rich insight and clarification into the thorough study of soil IR spectra. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1415416 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009
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Chemical process analysis: chemometrics; instrument control; applications in equilibrium and kinetic investigationsNorman, Sarah Elizabeth January 2008 (has links)
Research Doctorate - Doctor of Philosophy (PhD) / This work presents the development and application of modern data acquisition and analysis techniques for the investigations of equilibrium and kinetic reactions. The analytical technique is known as second order global analysis and a background of this relatively novel approach has been given. The theory behind and characteristics of the computer programs developed analysis as part of this research are described in Chapter Two along with descriptions of the instrumentation and programs developed for the acquisition of both potentiometric and spectrophotometric data. Applications of the developed programs include a potentiometric and spectrophotometric study of the protonation and stability equilibria of a series of polydentate N-donor ligands, as detailed in Chapter Three. The combination of potentiometric and spectrophotometric analysis has been shown to be a powerful analytical tool. Spectrophotometric titrations were also combined with fast stop-flow experiments in order to elucidate the complex reaction mechanisms associated with helicating ligands. The helication of the ligand ‘PepdaH₂’ with copper(II) and nickel(II) is examined in Chapter Four, along with discussions concerning the ability to induce chirality in the helicates from the addition of a chiral counter ion. Investigations into chirality were further continued in Chapter Five where the stereoselectivity of a benzimidazole-based ligand was investigated with circular dichroism titrations. The synthesis and characterisation of the benzimidazole-based ligands are provided, including a study of the ability of the ligands to form higher order complexes as investigated using electrospray mass spectroscopy. Chapter Six provides an in-depth discussion concerning the use of combined glass hydrogen selective electrodes for the determination of equilibrium constants, as this was a major focus of this research. Different calibration techniques are discussed and a description of the internal calibration technique developed is provided along with examples of the advantages of performing internal calibration of the electrode.
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Infrared spectroscopy and advanced spectral data analyses to better describe sorption of pesticides in soils.Forouzangohar, Mohsen January 2009 (has links)
The fate and behaviour of hydrophobic organic compounds (e.g. pesticides) in soils are largely controlled by sorption processes. Recent findings suggest that the chemical properties of soil organic carbon (OC) significantly control the extent of sorption of such compounds in soil systems. However, currently there is no practical tool to integrate the effects of OC chemistry into sorption predictions. Therefore, the K [subscript]oc model, which relies on the soil OC content (foc), is used for predicting soil sorption coefficients (K[subscript]d) of pesticides. The K[subscript]oc model can be expressed as K[subscript]d = K[subscript]oc × foc, where K[subscript]oc is the OC-normalized sorption coefficient for the compound. Hence, there is a need for a prediction tool that can effectively capture the role of both the chemical structural variation of OC as well as foc in the prediction approach. Infrared (IR) spectroscopy offers a potential alternative to the K[subscript]oc approach because IR spectra contain information on the amount and nature of both organic and mineral soil components. The potential of mid-infrared (MIR) spectroscopy for predicting K[subscript]d values of a moderately hydrophobic pesticide, diuron, was investigated. A calibration set of 101 surface soils from South Australia was characterized for reference sorption data (K[subscript]d and K[subscript]oc) and foc as well as IR spectra. Partial least squares (PLS) regression was employed to harness the apparent complexity of IR spectra by reducing the dimensionality of the data. The MIR-PLS model was developed and validated by dividing the initial data set into corresponding calibration and validation sets. The developed model showed promising performance in predicting K[subscript]d values for diuron and proved to be a more efficacious than the K[subscript]oc model. The significant statistical superiority of the MIR-PLS model over the K[subscript]oc model was caused by some calcareous soils which were outliers for the K[subscript]oc model. Apart from these samples, the performance of the two compared models was essentially similar. The existence of carbonate peaks in the MIR-PLS loadings of the MIR based model suggested that carbonate minerals may interfere or affect the sorption. This requires further investigation. Some other concurrent studies suggested excellent quality of prediction of soil properties by NIR spectroscopy when applied to homogenous samples. Next, therefore, the performance of visible near-infrared (VNIR) and MIR spectroscopy was thoroughly compared for predicting both foc and diuron K[subscript]d values in soils. Some eleven calcareous soils were added to the initial calibration set for an attempt to further investigate the effect of carbonate minerals on sorption. MIR spectroscopy was clearly a more accurate predictor of foc and K[subscript]d in soils than VNIR spectroscopy. Close inspection of spectra showed that MIR spectra contain more relevant and straightforward information regarding the chemistry of OC and minerals than VNIR and thus useful in modelling sorption and OC content. Moreover, MIR spectroscopy provided a better (though still not great) estimation of sorption in calcareous soils than either VNIR spectroscopy or the K[subscript]oc model. Separate research is recommended to fully explore the unusual sorption behaviour of diuron in calcareous soils. In the last experiment, two dimensional (2D) nuclear magnetic resonance/infrared heterospectral correlation analyses revealed that MIR spectra contain specific and clear signals related to most of the major NMR-derived carbon types whereas NIR spectra contain only a few broad and overlapped peaks weakly associated with aliphatic carbons. 2D heterospectral correlation analysis facilitated accurate band assignments in the MIR and NIR spectra to the NMR-derived carbon types in isolated SOM. In conclusion, the greatest advantage of the MIR-PLS model is the direct estimation of Kd based on integrated properties of organic and mineral components. In addition, MIR spectroscopy is being used increasingly in predicting various soil properties including foc, and therefore, its simultaneous use for K[subscript]d estimation is a resource-effective and attractive practice. Moreover, it has the advantage of being fast and inexpensive with a high repeatability, and unlike the K[subscript]oc approach, MIR-PLS shows a better potential for extrapolating applications in data-poor regions. Where available, MIR spectroscopy is highly recommended over NIR spectroscopy. 2D correlation spectroscopy showed promising potential for providing rich insight and clarification into the thorough study of soil IR spectra. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1415416 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009
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HPLC method development for characterisation of the phenolic composition of Cyclopia subternata and C. maculata extracts and chromatographic fingerprint analysis for quality controlSchulze, Alexandra Elizabeth 12 1900 (has links)
Thesis (MScFoodSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The phenolic composition of Cyclopia species is believed to be partially responsible for the numerous health
promoting properties associated with their extracts. Current quality control measures do not accommodate
variation in phenolic profiles of Cyclopia species. In this study, comprehensive high performance liquid chromatography
(HPLC) methods were developed for the improved characterisation of the phenolic composition of
aqueous extracts of two Cyclopia species (C. subternata and C. maculata). The methods were developed to be
suitable for both routine quantitative analysis on conventional HPLC instrumentation, and the construction of
chromatographic fingerprints for further data analysis. The latter entailed similarity analysis and prediction of
total antioxidant capacity (TAC).
Using a methodical approach, two separate HPLC methods, using diode array detection (DAD), were developed
and validated for the analysis of aqueous extracts prepared from unfermented (green) and fermented
plant material of C. subternata and C. maculata. Separation was achieved using the same method parameters
(column, temperature, mobile phases), except for differing mobile phase gradients. Hyphenation of
the developed HPLC methods with mass spectrometry (MS) and tandem MS allowed the confirmation of
phenolic compounds previously identified in Cyclopia, and the tentative identification of several additional
compounds in Cyclopia species, which are reported here for the first time. These included apigenin-6,8-di-
C-glucoside, 3-hydroxyphloretin-30,50-di-C-hexoside, eriodictyol-di-C-glucoside, iriflophenone-di-O,C-hexoside,
hydroxymangiferin and hydroxyisomangiferin. Subsequently, a large number of aqueous extracts of randomly
selected green C. subternata (n = 64) and C. maculata (n = 50) plant material samples were analysed. Large
quantitative variations were observed on intra- and inter-species levels. Cyclopia maculata extracts contained
almost six times more mangiferin than extracts from C. subternata.
HPLC-DAD analysis produced duplicate fingerprints for each extract which were consequently used for
further analysis. The chromatographic fingerprint of a bioactive extract of each species was included in the
respective data sets. Similarity analysis was conducted between the fingerprints from the randomly selected
extracts and the corresponding active extract. For each species several extracts were determined to have similar
“activity” as that of the active extract (n = 15 for C. subternata and n = 45 for C. maculata). Compounds
potentially responsible for the activity were tentatively identified with the aid of principal component analysis
(PCA) in combination with similarity analysis. PCA was more effective in identifying small differences between
fingerprints than similarity analysis based on the correlation coefficients (r) alone.
Furthermore, multivariate data analysis was used to construct partial least squares (PLS) regression models
for the prediction of TAC from fingerprint data of each species, and available data from two microplate TAC
assays. The construction of the models was successful with reasonable errors (< 10%), and permitted the
determination of compounds of interest for future research. These included compounds of known identity that
had large positive contributions toward the predictions of TAC, or unknown compounds that had small UV signals, but relatively large positive contributions to the models. / AFRIKAANSE OPSOMMING: Die talle gesondheidbevorderingseienskappe van ekstrakte van Cyclopia spesies word gedeeltelik geassosieer met
hul fenoliese samestelling. Huidige kwaliteitskontrolemaatreëls is nie in staat om die variasie wat in die fenoliese
profiele van die spesies voorkom, te akkommodeer nie. Omvattende hoë druk vloeistof chromatografiese (HPLC)
metodes is vir twee Cyclopia spesies, naamlik C. subternata en C. maculata, in hierdie studie ontwikkel vir beter
karakterisering van die fenoliese samestelling van waterekstrakte van dié spesies. Die metodes moes ook geskik
wees vir roetine analise van C. subternata en C. maculata ekstrakte op konvensionele HPLC instrumentasie,
en vir die opstel van chromatografiese vingerafdrukke (fenoliese samestellingsprofiele) vir verdere data analise,
soos gelykvormigheidsanalise en die voorspelling van die totale antioksidantkapasiteit (TAC).
Twee HPLC metodes, wat van ’n ultraviolet-diode detektor (DAD) gebruik maak, is ontwikkel deur ’n
sistematiese benadering te volg. Die onderskeie metodes is vir die ontleding van waterekstrakte van groen (ongefermenteerde)
en gefermenteerde plantmateriaal van C. subternata en C. maculata gevalideer. Ongeag die
spesie is optimale skeiding met dieselfde kolom, mobiele fase en kolom-temperatuur bereik, maar met verskillende
mobiele fase gradiënte. Analise met massaspektrometrie (MS) en tandem MS het die teenwoordigheid
van fenoliese verbindings, wat voorheen in Cyclopia spesies geidentifiseer is, bevestig. Verder is ook ’n aantal
verbindings vir die eerste keer in Cyclopia tentatief geidentifiseer. Dit sluit apigenien-6,8-di-C-glukosied, 3-
hidroksiefloretien-30,50-di-C-heksosied, eriodiktiol-di-C-glukosied, iriflofenoon-di-O,C-heksosied, hidroksiemangiferien
en hidroksie-isomangiferien in. Vervolgens is ’n groot aantal ewekansig gekose waterekstrakte van beide
groen C. subternata (n = 64) en C. maculata (n = 50) plantmateriaal geanaliseer, en groot kwantitatiewe variasie
op intra- en inter-spesievlak waargeneem. Cyclopia maculata ekstrakte het byvoorbeeld byna ses maal die
mangiferieninhoud van C. subternata ekstrakte gehad.
HPLC-DAD analise van die ekstrakte het duplikaat vingerafdrukke van elke ekstrak geproduseer, wat vir
verdere data analise gebruik is. Die chromatografiese vingerafdruk van ’n bioaktiewe ekstrak van elke spesie
was by die onderskeie datastelle ingesluit. Gelykvormigheidsanalise is tussen vingerafdrukke van die ewekansig
gekose ekstrakte en die ooreenstemmende aktiewe ekstrak uitgevoer. Vir elke spesie is ’n aantal “aktiewe”
ekstrakte aangewys (n = 15 vir C. subternata en n = 45 vir C. maculata). Die verbindings wat potensieel
verantwoordelik kan wees vir die aktiwiteite is met behulp van hoofkomponentontleding (PCA) in kombinasie
met gelykvormigheidsanalise, tentatief aangewys. PCA was egter meer effektief om klein verskille tussen vingerafdrukke
aan te dui, in vergelyking met gelykvormigheidsanalise wat slegs op die korrelasie koëffisiënt (r)
gebaseer is.
Meerveranderlike data analiese is gebruik om “gedeeltelike kleinste kwadrate” (PLS) regressiemodelle, vir
die voorspelling van die TAC van beide spesies te bou. Die voorspelling is gebaseer op hul vingerafdruk data en
TAC data van twee TAC mikroplaat metodes. Die model-konstruksie was suksesvol met aanvaarbare voorspellingsfoute
(< 10%). Verbindings van belang kon ook bepaal word. Dit sluit bekende verbindings in wat groot positiewe bydraes ten opsigte van die voorspelling van TAC getoon het, asook ongeidentifiseerde verbindings
wat klein UV-seine getoon het, maar relatiewe groot bydraes tot die modelle gehad het.
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Controle de qualidade de biodieseis de macaúba e algodão e suas misturas com o diesel usando Espectrometria no Infravermelho Médio e Cartas de Controle Multivariadas / Quality control of macaúba and cotton biodiesels and their diesel blends usind MID Spectrometry and Multivariate Control ChartsGuimarães, Eloiza 23 February 2018 (has links)
CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / A Lei nº 13.033/2014 estabelece a adição de 7 ± 0,5% (v/v) de biodiesel ao óleo diesel utilizado no sistema viário e proíbe a adição de óleos vegetais ou quaisquer solventes nesta mistura. No entanto, há casos de adição irregular de óleos vegetais e/ou residuais no diesel devido, principalmente, ao baixo custo destas matérias-primas em comparação com o produto final ou contaminado durante seu transporte e armazenamento. Assim, são necessárias análises que forneçam respostas imediatas e eficientes para garantir a qualidade dos combustíveis comercializados. Nesse sentido, o presente trabalho propõe o monitoramento da qualidade das misturas biodiesel/diesel (7% de biodiesel e 93% de diesel) usando a Espectrometria no Infravermelho Médio associada a Cartas de Controle Multivariadas baseadas no sinal analítico líquido (NAS). Os biodieseis foram produzidos a partir de óleos de macaúba e algodão usando metanol e etanol. Para cada modelo, foram desenvolvidas três cartas (gráficos): a Carta NAS, que corresponde ao analito de interesse (nesse caso o biodiesel), a carta interferente, relacionadas às contribuições de outros componentes na amostra (diesel), e a carta resíduo correspondendo à variação não sistemática nos espectros (ruído instrumental). Foram analisadas 1508 amostras utilizadas na calibração e validação de seis modelos (biodieseis etílicos e metílicos de algodão, biodieseis metílicos da amêndoa da macaúba, biodieseis metílicos e etílicos do mesocarpo da macaúba, e também de B7 comercial). Na etapa de calibração foram usadas 103 amostras dentro das especificações de qualidade, amostras estas usadas para estabelecerem os limites estatísticos para cada carta. A etapa de validação se deu com amostras dentro e fora das especificações de qualidade (1405 amostras). A validação com amostras fora dos padrões de qualidade foi feita de duas maneiras: em relação ao teor de biodiesel no diesel e à presença de adulterantes no biodiesel, no diesel e na mistura. A presença de adulterantes se deu por substituição parcial do biodiesel por óleos de soja, milho e residual, substituição parcial do diesel por óleo lubrificante, querosene e gasolina e por adição direta dos adulterantes citados na mistura biodiesel/diesel (B7) na faixa de 3,5 a 43,5% (v/v) correspondendo a uma faixa de adulteração de 0,2 a 30% (v/v) na mistura. Assim, foi possível separar as amostras conformes e não conformes tanto em relação ao teor de biodiesel no diesel quanto à presença de adulterantes, uma vez que as amostras dentro das especificações ficaram dentro dos limites estabelecidos e as amostras fora das especificações saíram do limite em pelo menos uma das cartas. Desta maneira, os resultados mostraram que o método descrito neste trabalho é uma alternativa viável, eficiente e rápida no controle de qualidade de biocombustível. / The Law No. 13.033/2014 establishes the addition of 7 ± 0.5% (v/v) of biodiesel to the diesel used in the road system and prohibits the addition of vegetable oils or any solvents to this mixture. However, there are cases of irregular addition of vegetable and/or waste oils in diesel, mainly due to the low cost of these raw materials when compared to the final or contaminated product during transportation and storage. Thus, analyzes are necessary to provide immediate and efficient responses in order to ensure the quality of the marketed fuels. In this sense, the present study proposed the quality monitoring of biodiesel/diesel blends (7% biodiesel and 93% diesel) through the use of the Medium Infrared Spectrometry associated with Multivariate Control Charts based on the liquid analytical signal (NAS). Biodiesel was produced from macaúba (acrocomia aculeate) and cotton oils using methanol and ethanol. For each model, three charts were developed: the NAS Chart, which corresponds to the analyte of interest (in this case biodiesel); the interfering chart, related to the contributions of other components in the sample (diesel); and the waste chart, corresponding to non-systematic variation in spectra (instrumental noise). A total of 1508 samples were used for the calibration and validation of the six models (ethyl and cotton biodiesel, macaúba almond (acrocomia aculeate) methyl biodiesel, macaúba mesocarp (acrocomia aculeate) methyl and biodiesel, and also commercial B7 biodiesel). At the calibration stage, 103 samples were used within the quality specifications, these samples were used to establish the statistical limits for each chart. The validation step was carried out with samples within and out of the quality specifications (1405 samples). The validation with non-standard quality samples was carried out in two ways: in relation to the biodiesel content in diesel and the presence of adulterants in biodiesel, diesel and blend. The presence of adulterants was due to the partial replacement of biodiesel by soybean, corn and residual oils; the partial replacement of diesel by lubricating oil, kerosene and gasoline; and by direct addition of the adulterants mentioned in the biodiesel/diesel blend (B7) in the range of
3.5 to 43.5% (v/v) corresponding to an adulteration range of 0.2 to 30% (v/v) in the blend. Thus, it was possible to separate the conforming and non-conforming samples, both regarding the biodiesel content in diesel and the presence of adulterants, since the samples within the specifications were within the established limits, and the samples out of the specifications have exceeded the limit in least one of the charts. Thus, the results have showed that the method described in this study is a viable, efficient and fast alternative to the biofuel quality control. / Tese (Doutorado)
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Fabricação de biossensor óptico de glicose em alumina anódica porosaFerro, Letícia Mariê Minatogau 31 March 2016 (has links)
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Previous issue date: 2016-03-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Porous anodic alumina (PAA) has been used as platform for the manufacture of optical sensors. Itshows chemical resistance, thermal stability, hardness, biocompatibility, high surface area which facilitates interaction with the analyte and good morphological organization with the possibility to manipulate its pore size. Furthermore, PAA shows optical responses characterized by Fabry-Pérot interferences that can be obtained by photoluminescence and reflectance spectroscopy. Besides the surface of the AAP can be modified by Layer-by-Layer technique (LbL) in order to enhance optical sensors. Changes in Fabry-Pérot interferences can be monitored and analyzed as sensor responses. In this work, LbL film were deposited using hydrochloride polyallylamine (PAH) and glucose oxidase (GOx) for the purpose of manufacturing an optical biosensor for glucose detection. A protective bilayer of PAH and poly (vinyl sulfonic acid) (PVS) was assembled. The growth of the films were monitored by photoluminescence and total reflectance techniques. In addition, biosensor tests were carried out by immersing PAA in glucose solutions with different concentrations in order to check for changes in Fabry-Pérot oscillations. Analyzing the results, orderly growth of LbL film and biosensor response were verified. Results of the biosensor test were characterized by displacements of Fabry-Pérot interferences to shorter wavelengths and by multivariate analysis. Limit of detection determined by qualitative analysis of the Fabry-Pérot oscillations was 0.1 mol.L-1 to both PAA without surface modification and modified PAA. By using partial least squares (PLS) regression, it was possible to determine glucose from 0.1 mol.L-1 with PAA without modification and 0.01 mol.L-1 for PAA with LbL film. Furthermore, it was also verified the viability of using chemometrics to examine Fabry-Pérot interferences obtained with the PAA as an alternative method shown in the literature, which involves concepts of Fabry-Pérot equation. / A alumina anódica porosa (AAP) vem sendo utilizada como plataforma na fabricação de sensores ópticos por apresentar resistência química, estabilidade térmica, dureza, biocompatibilidade, grande área superficial que facilita a interação com o analito e boa organização morfológica com a possibilidade de se manipular as dimensões de seus poros. Além disso, a AAP apresenta respostas ópticas caracterizadas pelas interferências de FabryPérot, que podem ser obtidas por espectroscopia de fotoluminescência e de reflectância. A superfície da AAP ainda pode ser modificada pela técnica de deposição por camadas, Layerby-Layer (LbL), com o intuito de se aprimorar esses sensores ópticos, sendo que mudanças nas interferências de Fabry-Pérot podem ser acompanhadas e analisadas como resposta do sensor. Neste trabalho, houve a deposição de filmes LbL de polialilamina hidroclorada (PAH) e de glicose oxidase (GOx), contendo um colchão de PAH e de ácido poli(vinil sulfônico) (PVS), com a finalidade de fabricação de um biossensor óptico de glicose. O crescimento dos filmes foi acompanhado por fotoluminescência e reflectância total. Além disso, testes dos biossensores foram realizados imergindo a AAP em soluções de glicose com concentrações diferentes a fim de se verificar alterações nas oscilações apresentadas nos espectros. A partir dos resultados obtidos foram verificados o crescimento ordenado do filme LbL e a resposta do biossensor, que foi caracterizada pelo deslocamento das interferências de Fabry-Pérot para comprimentos de onda menores e por análise multivariada. O limite de detecção determinado através da análise qualitativa das oscilações de Fabry-Pérot foi de 0,1 mol.L-1 de glicose, tanto para a AAP sem modificação superficial, quanto para a modificada. Com o emprego da regressão por mínimos quadrados parciais (PLS, do inglês “partial least squares”) foi possível a determinação de glicose a partir de 0,1 mol.L-1 para a AAP sem modificação e de 0,01 mol.L-1 para a AAP com filme LbL. Além disso, foi verificada também a viabilidade de se utilizar a quimiometria para analisar as interferências de Fabry-Pérot obtidas com a AAP como um método alternativo do apresentado na literatura, que envolve conceitos da equação de Fabry-Pérot.
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A estratégia de injeções consecutivas em cromatografia gasosa aplicada à rotina de análise de antioxidantes em polietilenoLopes Neto, Vanjoaldo dos Reis January 2006 (has links)
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Dissertação Vanjoaldo dos Reis Lopes Neto.pdf: 848318 bytes, checksum: 4fe600f95ca5b05beaeda33a5f367dba (MD5) / A automação é uma das tendências da Química Analítica Moderna e esta visa
o aumento da produtividade sem afetar a qualidade dos resultados, melhorar a
segurança do operador e minimizar possíveis impactos ao ambiente. Na mesma
frente, deve ser citada a quimiometria, a qual permite extrair o máximo de
informações químicas com menor número de observações. Nesta lógica, diferentes
estratégias têm sido desenvolvidas para aumentar a produtividade das
determinações cromatográficas.
Nas análises cromatográficas é usual que uma nova injeção da amostra seja
feita após a eluição de todos os componentes da alíquota da amostra anteriormente
injetada, mas aplicando critérios de lógica associada à automação, foi possível
incrementar a produtividade analítica sem afetar a qualidade dos resultados,
aplicando o conceito de injeções consecutivas. O procedimento foi aplicado nas
determinações de aditivos em polietileno, com amostras cedidas pela Braskem S.A.
Foi desenvolvido um software em QuickBasic 4.5 para estabelecer os
intervalos de tempo entre as consecutivas injeções para que não ocorressem
sobreposições dos picos dos componentes de interesse com outros picos oriundos
de alíquotas anteriormente inseridas.
Os três aditivos avaliados (Irganox 1076, Irgafós 168 e Irgafós 168oxi) foram
determinados em 45 amostras de polietileno, com redução do tempo total de
operação de 38 para 13,5 h. Os resultados obtidos pela metodologia proposta não
apresentaram diferenças significativas frente aos obtidos pelo método convencional
empregado nas rotinas analíticas da Braskem, para 95% de confiabilidade. / Automation is one of the tendencies of Modern Analytical Chemistry and it
aims the increase of analytical productivity without detriment of results, the
improvement of operator security and to minimize the possibility of environmental
impact. In the same way chemometrics deserves prominence since it allows
maximization of extraction chemical information with minimal number of experiments.
This logic has been employed to develop different strategies to increase the
productivity of chromatographic determinations without detriment of quality results.
In chromatographic analysis it is usual that a new injection is carried out after
elution of all components of related to prior injection, but with logical criteria coupled
to automation it was possible to increase analytical productivity with the concept of
successive injection. The procedure was applied in the determination of polyethylene
additives in Braskem S.A. samples.
A QuickBasic 4.5 software was developed in order to define the time intervals
between successive injection that did not leads to analyte peaks carryover with peaks
from prior injection.
Three additives were evaluated (Irganox 1076, Irgafós 168 and Irgafós 168oxi)
and determined in 45 polyethylene samples with reduction of 38 for 13,5 h of total
determination time. The results obtained by proposed methodology were compared
with those ones obtained by conventional methodology employed in Braskem
analytical routines, and they agreed at 95% confidence level.
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Desenvolvimento e validação de metodologia analítica para determinação de cloridrato de tizanidina em formas farmacêuticasBrandalise, Mariana January 2012 (has links)
O objetivo deste trabalho foi o desenvolvimento e a validação de métodos analíticos para determinação de cloridrato de tizanidina (TZ) matéria-prima e forma farmacêutica. Na fase de identificação, a matéria-prima (substância química de referência) foi analisada e caracterizada utilizando-se medidas físicas (ponto de fusão e solubilidade), espectrometria no infravermelho e por técnicas cromatográficas (cromatografia líquida de alta eficiência e cromatografia em camada delgada). Após foi desenvolvido e validado método analítico para o doseamento de cloridrato de tizanidina matéria-prima utilizando a titulação por volumetria em meio não-aquoso, que pode ser realizada em estabelecimentos de pequeno porte. No estágio posterior, para quantificação da forma farmacêutica utilizou-se desenhos experimentais (fatorial fracionado e desenhos de composto central). O método CLAE com detector Charged Aerosol Detection (CAD) foi validado e um produto de degradação foi obtido na condição de degradação de estresse oxidativo (H2O2 13%). Foi também quantificado o cloreto presente na molécula. Tanto a volumetria em meio não-aquoso com determinação do ponto final por indicador, quanto o método cromatográfico foram comparados com métodos descritos em compêndios oficiais e não demonstraram diferença significativa quando aplicados ao doseamento da matéria-prima e forma farmacêutica, respectivamente. / The aim of this work was the development and validation of analytical methods for determination of tizanidine hydrochloride (TZ) raw material and dosage form. In the identification phase, the raw material drug (chemical reference) was analyzed and characterized using physical measures (melting point and solubility), infrared spectrophotometry and chromatographic techniques (high performance liquid chromatography and thin layer chromatography). An analytical method for assay of tizanidine hydrochloride raw material was developed and validated by using volumetric titration in a non-aqueous liquid, which can be performed in small establishments. In a later stage, for the measurement of the dosage form an experimental design was used (fractional factorial and centered composite design. The HPLC method with charged aerosol detection (CAD) was validated and a degradation product was obtained under the oxidative stress condition (H2O2 13%). Chloride present in the molecule also was quantified. Both, the non-aqueous titration method with coloured indicator and the chromatographic one were compared to the methods described in official compendia and do not present significant difference when applied to the determination of the raw material and dosage form, respectively.
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Fingerprinting de cocaína : um estudo do perfil químico no estado do Espírito SantoSouza, Lindamara Maria 28 March 2014 (has links)
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tese_7529_Lindamara Maria de Souza20140630-82317.pdf: 3532286 bytes, checksum: 2c24c77fad763f25826fe7fa50a73f20 (MD5) / CAPES / A cocaína é uma droga estimulante do Sistema Nervoso Central (SNC) e um potente anestésico local. A duração de seus efeitos depende da forma consumida (sal, principalmente o cloridrato de cocaína, ou de base, de base livre ou crack) e no modo de administração (injetando, aspiração ou o fumo). A cocaína é definida como um alcaloide tropânico por apresentar em sua estrutura o núcleo tropano. Entretanto, apesar de sua composição definida, com a finalidade de diluir e aumentar o volume final da droga, o mercado ilícito se utiliza de uma grande diversidade de aditivos químicos como benzocaína, lidocaína, cafeína, procaína, entre outros. Esta dissertação foi dividida em três capítulos destinados a: i) avaliar o teste colorimétrico, ou seja, o teste de Scott, usando a espectroscopia de infravermelho com transformada de Fourier utilizando acessório de reflexão total atenuada (ATR-FTIR). Dezessete aditivos químicos foram avaliados, onde quatro forneceram resultados falsos positivos (prometazina, lidocaína, leite em pó e fermento). Quando o teste de Scott é realizado e aliado a técnicas espectroscópicas como ATR-FTIR e quimiometria, resultados conclusivos são obtidos e podem ser usados à rotina de laboratórios forenses. ii) Foi estudado o perfil químico orgânico de amostras de cocaína apreendidas no ano de 2012 nos meses de janeiro a julho usando a cromatografia gasosa acoplada a um espectrometro de massas quadrupolar (GC-MS). Neste capítulo, 101 amostras foram analizadas no modo full scan e 83 destas usadas para construção de um modelo quimiométrico usando a análise de componentes principais (PCA). Os principais adulterantes encontrados foram lidocaína, fenacetina e cafeína. Adicionalmente, cocaína, lidocaína e cafeína foram quantificadas a partir do monitoramento do íon selecionado (SIM) e seus valores de linearidade, limites de detecção e quantificação determinados. iii) as amostras de cocaína apreendidas pela polícia civil foram classificadas em função do tempo (2008, 2009, 2010, 2011 e 2012) e da localização de apreensão (em função das quatro macrorregiões do estado) usando a técnica de GC-MS aliada à análise multivariada (PCA), onde um total de 512 amostras foram investigadas. / Cocaine is a central nervous system (CNS) stimulant drug that causes psychological dependence. The duration of its effects depends on the form consumed (salt, e.g. cocaine hydrochloride, or base, e.g. crack) and on the mode of administration (snorting, smoking or injecting). Cocaine is defined as a tropanic alkaloid present in its structure by the tropane core. Despite its defined composition, aiming to increase the final amount of drug, illicit market applies a wide variety of diluent chemicals such as benzocaine, lidocaine, caffeine, procaine, among others. This project was divided into three chapters dedicated to: i) evaluating colorimetric, ie, the Scott test, using infrared spectroscopy with Fourier transform using Attenuated Total Reflection accessory (ATR-FTIR). Seventeen chemical additives were evaluated, which provided four false positives (promethazine, lidocaine, powdered milk and yeast). As the Scott test is performed and combined with spectroscopic techniques such as ATR-FTIR and chemometrics, conclusive results are obtained and can be used for routine forensic laboratories. ii) organic chemical profile of samples seized in the year 2012 in the months from January to July were analyzed using gas chromatography coupled to a quadrupole mass spectrometer (GC-MS) was studied. In this chapter, 101 samples were analyzed in full scan mode and 83 of these used to construct a model of principal component analysis (PCA). The main adulterants found were lidocaine, phenacetin and caffeine. Additionally, cocaine, lidocaine and caffeine were quantified from the selected ion monitoring (SIM), and their values of linearity, limits of detection and quantification determined. iii) samples of cocaine seized by the Civil Police were classified according to the time (2008, 2009, 2010, 2011 and 2012) and the location of apprehension (in relation to the four geographical regions of the state) using the technique of GC-MS associated with multivariate analysis (PCA), where a total of 512 samples were investigated.
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