Regensburg, Univ., Diss., 2008

Techn. University, Diss., 2000--Berlin.

Techn. Universiẗat, Diss., 2003--Clausthal. / Enth.: Bd. 1. Dissertation. Bd. 2. Techn. Dokumentation.

Universiẗat, Diss., 2003--Bonn.

Univ., Diss., 2002--Frankfurt (Main) / Zsfassung in dt. Sprache

A matéria orgânica do solo (MOS) representa um importante reservatório de carbono (C) nos ecossistemas terrestres. O conteúdo de C estocado no solo pode ser liberado para a atmosfera na forma de CO2, com a decomposição da MOS, ou pode ser aumentado com a entrada de resíduos e retenção da MOS. Nesse sentido, é importante entender os mecanismos de estabilidade e retenção da MOS para predizer como os solos respondem a mudanças, quer sejam elas induzidas por alterações climáticas ou por práticas de manejo. Dentro dos Latossolos, classe que ocupa cerca de 32 % do território brasileiro, há aqueles que possuem horizonte A húmico hiper espesso e, portanto, com maior estoque de C. Aspectos sobre a origem, formação e preservação do horizonte A húmico destes solos em suas ocorrências em diferentes biomas ainda não foram completamente elucidados e estão estritamente ligados à fonte, dinâmica e mecanismos de preservação e distribuição da MOS no solo. O objetivo deste trabalho é entender a gênese da MO dos Latossolos húmicos que ocorrem no Bioma Cerrado, por meio da caracterização molecular pela técnica da pirólise acoplada à cromatografia gasosa e espectroscopia de massas (pirólise - CG/EM). Para isso, foram coletadas amostras dos horizontes A em dois perfis de Latossolos com horizonte A húmico (LH1, LH2) e um perfil de Latossolo com horizonte A moderado (solo de referência; LNH) situados em superfície de aplanamento adjacente à Serra do Espinhaço, no município de Grão Mogol - MG, sob clima tropical semi-úmido e vegetação de cerrado sensu strictu. Por meio da descrição morfológica dos solos em diferentes níveis de observação (campo, lupa e microscópio) procurou-se entender melhor os mecanismos de espessamento do horizonte A e a distribuição de partículas de carvão ao longo do perfil. As amostras dos horizontes foram submetidas ao fracionamento físico e extração da MOS, gerando as seguintes frações: fração leve livre (FLL); fração leve oclusa (FLO), fração extraível com NaOH (EXT) e resíduo (RES). A morfologia dos perfis evidencia a intensa e longa atividade biológica (fauna e raízes) a que esses solos foram e estão submetidos. Isso explica a abundância de microagregados e a consequente macropososidade elevada, assim como a ampla distribuição de fragmentos de carvão em todo o horizonte A, e parte do B, com dimensões milimétricas a submilimétricas, sugerindo a fragmentação destes ao longo do tempo. Foi evidenciado o maior conteúdo de carvões nos dois LHs em comparação ao LNH. A distribuição da MOS nas frações estudadas foi a mesma para os três perfis estudados: RES>EXT>FLL>FLO, que mostra a importância da fração RES para estes solos. Produtos da carbonização (Black carbon; BC: hidrocarbonetos poliaromáticos) foram mais abundantes na fração RES e FLO, no entanto, a maior diferença qualitativa entre a MOS de LHs e LNH diz respeito à abundância de BC na fração RES, que é maior em LHs do que LNH; confirmando a maior quantidade de carvões em LHs verificada na morfologia. Um índice de degradação do BC foi estabelecido com base em análise fatorial com os todas as frações estudadas e produtos poliaromáticos. Este índice, aplicado às frações EXT e RES, mostrou que a degradação do BC aumenta com a profundidade/idade, e não houve diferenças significativas entre os perfis estudados. Portanto, LHs provavelmente tem maior entrada de carvões, o que deve estar ligado a um histórico de maior incidência de incêndios ou maior abundância local de espécies arbóreas. / Soil organic matter (SOM) is an important carbon (C) stock in terrestrial ecosystems. C in soils can be released to the atmosphere in CO2 form by SOM decomposition, or can be stored with residue inputs and SOM retention in the soils. In this sense, it is important to understand the SOM stability mechanisms to predict how soils behave under climatic or human management induced environmental changes. Latosols occupy 40% of the national territory in Brazil. Some of them have a hyper thick A horizon with a major C stock, Humic Latasols. Aspects that underlie the formation of humic A horizon are still unclear, and mainly concern SOM dynamics, SOM preservation mechanisms, and SOM distribution with depth. The aim of this work is to understand the genesis of Humic Latosols through molecular characterization of SOM by pyrolysis coupled to gas chromatography and mass spectrometry (pyrolysis - GC/MS). For this purpose samples from two profiles (LH1, LH2) were collected, and in addition a reference profile was sampled (Latosol without humic characteristics, LNH). All profiles were located near Grão Mogol city (MG) under a semi-humid tropical climate and Cerrado vegetation. Morphology at different levels (field, bloom and microscope) showed that charcoal was abundant in all three profiles, and an extremely high biological activity. Profiles were sampled in detail and all samples were submitted to sequential physical fractionation and chemical extraction, generating the following SOM fractions: free light fraction (FLF); occluded light fraction (OLF); NaOH extractable fraction (EXT) and residue (RES). The molecular composition of the samples was studied by pyrolysis-GC/MS. Profile morphology evidence the long and intense biological activity (faunal and roots) in this soils, in the past and present time. This explains the microaggregate abundance and consequent macroporosity, and also the distribution of charcoal fragments in all of A and part of B horizon. These fragments have submilimetrical a milimetrical dimensions, suggests its fragmentation along the time. It was evidenced too, the bigger charcoal content in LHs than LNH. The C distribution in the fractions was the same for all the studied profiles: RES>EXT>FLL>FLO, which shows the importance of the RES fraction for these soils. Pyrolysis products derived from black carbon (BC; polyaromatics hydrocarbons) were most abundant in RES and FLO. In the RES, PAHs were more abundant in the LH than LNH; confirming the biggest quantity of charcoals in LHs verified in morphology. A BC degradation index was established using factor analysis with all PAH and all fractions studied. Depth records of these parameter showed an increase with depth in both EX and RES, and showed no differences between the studied profiles. It is concluded, therefore, that the LH had a larger input of charcoal. It is hypothesized that the larger contribution from BC in LHs is related to local differences in fire intensity and/or more trees in the vegetation.

The ability to locate human remains, specifically in a forensic setting, is crucial to investigations. Research in the past two decades has identified volatile organic compounds (VOCs) as the source of the decomposition odor. The study examined the headspace (area directly above) of decomposing remains, Sigma-Aldrich (St. Louis, MO) Pseudo Corpse Scents (formulations one and two), cadaveric blood, and decompositional fluid for target VOCs to which human remains detection (HRD) dogs could indicate. These samples were tested using solid-phase microextraction (SPME) and a gas chromatograph-mass spectrometer (GC/MS) for the exact odor profile and compared to literature about VOCs present in decomposition. The author hypothesized that a series of seven target chemical compounds (carbon disulfide, hexanal, nonanal, dimethyl sulfide, dimethyl disulfide, styrene, and benzoic acid methyl ester) would be present when the headspace of all samples tested. Ideally, a synthetic compound that will better mimic human decomposition odor profile can be created to aid in the training of HRD dogs. There are some disadvantages to using dogs in the field, and the lack of standardization when training HRD dogs is a major one. By examining VOC profiles of different sources of decomposition, a core set of VOCs of human decomposition may be identified to aid in the standardization of training. Of the eight target compounds chosen from the literature, only two were found in any samples tested for this experiment, hexanal and nonanal found in pig heart, deer liver, as well as human muscle and epidermis. Acetic acid was identified in every sample with the exception of the control. Also, in accordance with the literature, putrescine and cadaverine were not found in any of the samples.

Aerosols are either emitted directly into the atmosphere or are generated in the atmosphere; the latter process forms secondary organic aerosol (SOA). One of the important sources for SOA is the oxidation of volatile organic compounds (VOCs) by OH radicals, NOx, and O3. Aerosol can be visualized as suspended solid or liquid particle which is in equilibrium with surrounding gases. The products of SOA formation is a mixture of semi volatile organic compounds and a fraction of the products are condensable under atmospheric conditions. The condensable portion of aerosol is called particulate matter (PM) and these suspended particles can range in diameter from a few nanometers to microns. PM can impact climate through direct and indirect radiative forcing and can degrade air quality by reducing visibility and causing detrimental health effects. SOA can also form indoors, which also contributes to the health risk of PM. The severe impact of PM on human health and climate drives the scientific community to investigate the volatile organic compounds (VOCs) and their potential to form SOA, as well as the factors that alter the efficiency of SOA generation and the type of products. In a similar pursuit, the focus of this dissertation is the investigation of the SOA precursors that are emitted from trees and how they vary as a function of insect infestation. Also, the role of mixtures of VOCs as SOA precursors are investigated; commercial and lab made VOC mixtures are studied for SOA generation, product analysis, and absorption characteristics of aged SOA. Chapter 1 introduces PM, VOCs present in atmosphere, SOA generation, and speciation of products generated from the ozonolysis of VOCs. The impact of PM on human health and climate are summarized. A literature survey on the VOCs that are precursors to SOA and present in the outdoor and indoor environment is presented along with factors that may lead to variability in amount of VOCs. SOA generation from direct plant emissions and consumer products is surveyed. These studies show that VOC oxidation generate SOA which is important in the atmosphere due to climate and health effects and indoors due to health effects. A summary of SOA phase partitioning theories, the reaction mechanism for the formation of products from ozonolysis of the dominant biogenic SOA precursors (monoterpenes), and the factors that affect SOA generation is presented. Chapter 2 summarizes the results obtained from a field study assessing the impact of bark beetle infestation on SOA precursor emissions from forests in the Western United States. Samples of VOCs were collected by our collaborators from healthy and bark beetle infested trees using scent traps. We solvent extracted and analyzed by gas chromatography/mass spectrometry (GC/MS) nearly four hundred scent traps. An increase in the total and the individual VOCs emitted by infested trees was measured. A statistical analysis shows significant differences between the emissions from infested and healthy trees. A perspective is provided on potential impact of bark beetle infestation on regional SOA. The majority of the laboratory experiments for SOA generation have focused on individual VOCs as the single SOA precursor. However, as demonstrated in Chapter 2 for example, in a real environment multiple VOCs co-exist. Multiple SOA precursors undergo concurrent oxidation reactions, and it is not known if the products from concurrent oxidation of multiple precursors are the same as the sum of the products from individual SOA precursors. Mass closure analysis of field samples show that a significant fraction of the chemical identity of organic PM is unknown, but the chemistry impacts the toxicity of PM. Hence, it is important to understand SOA formation from realistic SOA mixtures. Chapter 3 describes the results of the SOA generation by ozonolysis of limonene and VOC mixtures containing limonene. We use an additive approach for building a surrogate VOC mixture close in composition to a commercially-available mixture. The yield of PM as a function of VOC precursor mixture was measured with respect to VOC composition using smog chamber SOA generation and scanning mobility particle sizing. PM in the chamber was collected onto filters and extracted, and the individual products of SOA were identified and quantified by GC/MS. The condensed-phase SOA products generated during these experiments for different VOC mixtures are compared. In Chapter 4, condensed-phase products sampled from SOA generated by the ozonolysis of α pinene and VOC mixtures containing α pinene, including two fir needle essential oils, are studied by extracting filter samples and analyzing the extracts by GC/MS. The products generated from VOC mixtures are characteristic of the most dominant VOC present in the mixture i.e. either limonene or α pinene. Some mixtures show the generation of new products which are not observed for corresponding individual VOC ozonolysis and hence can be used as marker for the corresponding VOC mixture. The distribution of α-pinene SOA products changes as the composition of the SOA precursor mixture changes. In Chapter 5, the UV visible absorption characteristics of ammonium ion aged SOA are discussed. Ammonium ion aging of aerosol leads impacts the radiative properties of aerosol and has the potential to impact aerosol's role in climate change. Filter samples containing SOA generated from two mixtures with different dominant monoterpenes (α-pinene-based Siberian fir needle oil and a limonene-based air freshener) were extracted. The absorption coefficients of the extracts were measured as a function of ammonium ion aging time using UV-visible absorption spectrometry. The conclusions from all above chapters are summarized in Chapter 6.

Linha de pesquisa: Tecnologia e vigil?ncia em sa?de. / Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2018-01-10T19:40:05Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) anderson_caldeira_oliveira.pdf: 1872739 bytes, checksum: 55f5678427b28e816e057b67c0d0cecc (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-01-19T17:14:17Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) anderson_caldeira_oliveira.pdf: 1872739 bytes, checksum: 55f5678427b28e816e057b67c0d0cecc (MD5) / Made available in DSpace on 2018-01-19T17:14:17Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) anderson_caldeira_oliveira.pdf: 1872739 bytes, checksum: 55f5678427b28e816e057b67c0d0cecc (MD5) Previous issue date: 2017 / O Brasil encontra-se entre os pa?ses de maior consumo de coca?na no mundo. As quest?es relacionadas ao uso da coca?na provocam preocupa??es, uma vez que s?o acompanhadas de consequ?ncias que atingem m?ltiplas dimens?es da sociedade moderna. Os problemas associados ao tr?fico e ao consumo de drogas est?o difundidos por todo o pa?s, alcan?ando, inclusive, munic?pios de pequeno porte. A presen?a de adulterantes pode ocasionar rea??es inesperadas bem como potencializar os danos ? sa?de dos usu?rios. Este trabalho teve como objetivo caracterizar amostras de coca?na apreendidas no munic?pio de Diamantina, Minas Gerais, quanto ao teor de coca?na e presen?a de adulterantes. Em uma primeira etapa do trabalho, foi validada uma metodologia anal?tica para quantifica??o de coca?na em amostras apreendidas com uso da Cromatografia Gasosa acoplada ? Espectrometria de Massas com monitoramento de ?ons selecionados (selected-ion monitoring - SIM) (CG-EM-SIM). Em uma segunda etapa, foram analisadas cento e vinte e nove amostras, sendo destas sessenta e sete apreendidas na forma de p? e sessenta e duas como crack. Foram realizadas an?lises para a identifica??o de adulterantes e para determina??o do teor de coca?na nas amostras, sendo a identifica??o de adulterantes realizada por Cromatografia Gasosa acoplada Espectrometria de Massas (CG-EM), no modo full scan, e a quantifica??o da coca?na por CG-EM?SIM. Foi realizada a compara??o do teor m?dio entre as amostras apreendidas na forma p? e de crack pelo teste U de Mann-Whitney. A fenacetina foi o principal adulterante encontrado. Outros adulterantes como benzoca?na, cafe?na, levamisol, lidoca?na e proca?na tamb?m foram detectados. As amostras apreendidas como crack apresentaram not?rio predom?nio da fenacetina como adulterante. O teor de coca?na das amostras estudadas apresentou varia??o dentro de um amplo intervalo (0-93%). Os teores m?dios de coca?na observados para as formas de p? e de crack foram, respectivamente, 31,7% e 54,3%, sendo tais valores estatisticamente distintos. A vigil?ncia em rela??o ?s caracter?sticas de drogas il?citas deve ser uma atividade cont?nua para fornecer aos ?rg?os de controle e de sa?de p?blica elementos de aux?lio ?s atividades de repress?o e tamb?m para tomadas de decis?o e de diagn?stico por parte dos profissionais de sa?de que lidam com atendimento aos usu?rios de drogas. As informa??es obtidas neste trabalho poder?o contribuir para futuras a??es de educa??o e conscientiza??o em rela??o aos riscos associados ao uso de drogas. / Disserta??o (Mestrado Profissional) ? Programa de P?s-Gradua??o em Sa?de, Sociedade e Ambiente, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / Brazil is among the countries with the highest cocaine use in the world. The issues related to cocaine use raise concerns, since they are accompanied by consequences that affect the modern society multiple dimensions. The problems associated with illicit trafficking and drug abuse are widespread throughout the country, reaching small towns. The adulterants presence can cause unexpected reactions as well as potentiate the damages to the users? health. This study aimed to characterize the cocaine samples seized in Diamantina, Minas Gerais, Brazil, regarding the cocaine content and the adulterants presence. In the study?s first phase, an analytical methodology was validated for the cocaine quantification in samples seized using Gas Chromatography coupled to a Mass Spectrometry with Selected-Ion Monitoring (GC-MS-SIM). In a second phase, one hundred and twenty-nine samples were analyzed, from which sixty-seven were seized as powder and sixty-two as crack. Analyzes were performed to identify adulterants and to determine the cocaine content in the samples. The identification of adulterants were carried out by a Gas Chromatography coupled to a Mass Spectrometry (GC-MS) in the full scan mode, and quantification of cocaine contend by GC-MS-SIM. The mean content comparison between the samples seized as powder and crack was performed by the Mann-Whitney U test. Phenacetin was the main adulterant found. Other adulterants such as benzocaine, caffeine, levamisole, lidocaine and procaine were also detected. The samples seized as crack showed a predominance of phenacetin as adulterant. The cocaine content of the samples studied varied within a wide range (0-93%). The average cocaine contents observed for the powder and crack forms were, respectively, 31,7% and 54,3%, and these values were statistically different. The surveillance in relation to the illicit drugs characteristics should be a continuous activity to provide control to the public health agencies with support elements for repression activities, as well as decision-making and diagnosis by the health professionals dealing with the drug users? care. The information obtained in this study may contribute to the future education and awareness actions regarding the risks associated with the drug use.

Physical and chemical properties of pesticides may vary significantly. Pesticides can be acidic, neutral or alkaline. Some compounds containing phosphorus, other sulfur, nitrogen or halogens. These atoms can be important for the detection of pesticides. Some of the compounds are volatile, others on the contrary not evaporate, which is also one of the important properties for chromatography. The diversity of pesticides actually makes it impossible to create a universal method, which is very impractical in terms of quality and time determination. Because that pesticides are one of the most chemicals in most countries. In the food and drinking water are limits on pesticides in order to avoid negative impact on public health. For residues in soil or surface water limits are set. (Lutz et al., 2006) The objective of this thesis is to evaluate the possibility of using two types of chromatographs with different detectors for the analysis of pesticide. Pendimethalin which was chosen for this work, will be analyzed usinga liquid chromatograph with UV detektor and gas chromatography with mass detector. Both this method will be compared as well two extraction methods (Soxhlet extraction and shaking), and two extraction agents (methanol and acetonitrile). Another point of the work is to provethe hypothesis that, for the determination of pendimethalin in soil is by gas chromatography using a mass spectrometer in comparison with the high performance liquid chromatography time and more expensive, but will achieve a higher yield and a lower detection limit of the pesticide.