Dissertations / Theses: 'Environmental sample analysis'

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Barnabas, Ian Joseph. "Sample preparation in environmental organic analysis." Thesis, Northumbria University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245205.

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Do, Lan. "New tools for sample preparation and instrumental analysis of dioxins in environmental samples." Doctoral thesis, Umeå universitet, Kemiska institutionen, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-70218.

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Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), two groups of structurally related chlorinated aromatic hydrocarbons, are of high concern due to their global distribution and extreme toxicity. Since they occur at very low levels, their analysis is complex, challenging and hence there is a need for efficient, reliable and rapid alternative analytical methods. Developing such methods was the aim of the project this thesis is based upon. During the first years of the project the focus was on the first parts of the analytical chain (extraction and clean-up). A selective pressurized liquid extraction (SPLE) procedure was developed, involving in-cell clean-up to remove bulk co-extracted matrix components from sample extracts. It was further streamlined by employing a modular pressurized liquid extraction (M-PLE) system, which simultaneously extracts, cleans up and isolates planar PCDD/Fs in a single step. Both methods were validated using a wide range of soil, sediment and sludge reference materials. Using dichloromethane/n-heptane (DCM/Hp; 1/1, v/v) as a solvent, results statistically equivalent to or higher than the reference values were obtained, while an alternative, less harmful non-chlorinated solvent mixture - diethyl ether/n-heptane (DEE/Hp; 1/2, v/v) – yielded data equivalent to those values. Later, the focus of the work shifted to the final instrumental analysis. Six gas chromatography (GC) phases were evaluated with respect to their chromatographic separation of not just the 17 most toxic congeners (2,3,7,8-substituted PCDD/Fs), but all 136 tetra- to octaCDD/Fs. Three novel ionic liquid columns performed much better than previously tested commercially available columns. Supelco SLB-IL61 offered the best overall performance, successfully resolving 106 out of the 136 compounds, and 16 out of the 17 2,3,7,8-substituted PCDD/Fs. Another ionic liquid (SLB-IL111) column provided complementary separation. Together, the two columns separated 128 congeners. The work also included characterization of 22 GC columns’ selectivity and solute-stationary phase interactions. The selectivities were mapped using Principal Component Analysis (PCA) of all 136 PCDD/F’s retention times on the columns, while the interactions were probed by analyzing both the retention times and the substances’ physicochemical properties.

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Ying, Lishi. "An automated direct sample insertion-inductively coupled plasma spectrometer for environmental sample analysis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq39610.pdf.

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Kappel, C. "An environmental and behavioural analysis of arson in a Danish sample." Thesis, University of Liverpool, 2018. http://livrepository.liverpool.ac.uk/3023901/.

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Background: Despite its significance as a costly and destructive criminal behaviour, there appears to be some consensus that we know relatively little about arson compared to many other areas of criminal behaviour. Moreover, most existing theory and research into arson has come from the USA, and has tended to concentrate on profiling the characteristics of offenders, rather than investigating, at least in any detail, features of the environment that may influence their behaviour. Aim: The main aim and overarching theme of the current thesis was, therefore, to describe and evaluate some of the main demographic and biographical characteristics, offence related behaviours, and environmental factors associated with arson, in a sample of arson offenders from a European country. Methods: Six empirical studies were conducted, each based on cases drawn from a sample of 746 cases committed by 540 offenders from Denmark between 2002 and 2010 in two police districts, one rural and one urban. Studies 1 and 2 examined a range of demographic and biographical characteristics of arson offenders (such as, gender and age); Studies 3 and 4 covered offence related behaviours (such as selection of targets, and travel distances), and employed regression analyses to look specifically at how these were predicted by other offence related and demographic and biographical variables. Study 5 then investigated the prediction of serial offending as an indicator of arson recidivism using the above demographic and biographical variables and offence related variables. Finally, Study 6 attempted to employ a new approach, via Google Earth, to examine the influence of a range of architectural and structural features of the environment on arson offending; these included 2 targets, presence of high rise buildings, territorial markers, population density and maintenance. Results and Discussion: Findings supported previous literature in identifying the typical arsonist as a young male offender; however, the results further suggested three possible divergent trends in the data corresponding to different categories of arson offender: 1) a more frequent opportunistic arsonist; 2) a less frequent, but more serious, often more persistent serial offender, and 3) a category of mainly female offenders who are less likely to be serial offenders but who may be reacting to dysfunctional home environments. Importantly, in relation to the latter finding, a bimodal peak in age emerged in the subgroup of female offenders, identifying a younger group of female offenders in their mid and late teen years and an older subgroup of female offenders in their late thirties and early forties. Another notable finding was that young male offenders who were not at school were particularly at risk for becoming serial offenders, suggesting that young males not attending school could be targeted in terms of prevention of persistent arson. Also, as predictors of arson, a number of environmental variables were significant and in line with predictions (for example, arson was more prevalant where there were vacant buildings, and very significantly, where the nearest police station was farthest away), but others were significant in a direction opposite to predictions (high building density was associated with lower rates of arson), and some potentially important predicted relationships failed to emerge as significant predictors (such as territorial markers). In addition to the above, two other major findings emerged. First, whilst it was possible be to predict crime scene behaviours from other crime scene behaviours with some degree of accuracy, and, similarly, demographic behaviours (like previous arson) from other demographic factors, predicting crime scene behaviours from demographic factors and vice versa proved to be considerably more difficult. In contrast, in terms of having 3 maximum impact on arson rates the environmental variables considered here did a relatively good job of predicting the presence of arson. A number of limitations and implications are also discussed. Conclusion Considering the results as a whole, notwithstanding some success in predicting arson from demographic and offence related variables, it is concluded that an extension of the kind of environmental approach explored in this thesis could potentially be used for developing environmental schemes for arson prevention that might be considerably easier to apply, and perhaps even more effective in reducing arson, than targeting 'at risk' groups of individuals.

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Lam, Rebecca. "Investigation of two solid sample introduction techniques for the analysis of biological, environmental, and pharmaceutical samples by inductively coupled plasma spectrometry." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102993.

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In this thesis, new approaches to direct trace metals analysis of solid samples by inductively coupled plasma spectroscopy were investigated using laser ablation and thermal vaporization systems for solid sample introduction of biological, environmental, and pharmaceutical samples.
Laser ablation with inductively coupled plasma atomic emission spectroscopy (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) was applied to pharmaceutical tablets. Precision of analysis depended on laser parameters and could be improved using signal ratios. The feasibility of using laser ablation-ICP-MS for detecting natural levels of mercury along a single human hair strand was also demonstrated.
As well, the use of an induction-heating electrothermal vaporizer (IH-ETV) coupled to an ICP-MS was successful in determining mercury concentrations in a single human hair strand. Methodologies for multielement analysis of powdered hair were also explored using IH-ETV-ICP-MS. While calibration by reference hair materials showed promise, calibration methods by liquid standards were not suitable for any element. Detection limits achieved for most elements were below natural levels found in human hair.
IH-ETV-ICP-AES was also applied to the analysis of analyze-laden chromatographic powder. This study showed potential problems that may arise due to the methodology taken to analyze such materials. Finally, recommendations for future investigations and methodologies for laser ablation and thermal vaporization are discussed.

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Mesa, Rodolfo. "Simplifying Sample Preparation using Fabric Phase Sorptive Extraction: Analysis of Trace Targeted Pollutant Residues in Environmental, Biological and Food Samples." FIU Digital Commons, 2017. https://digitalcommons.fiu.edu/etd/3513.

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Sample preparation is an essential component of analytical methods in chemistry. It is not only necessary but also presents an opportunity to increase the effectiveness of the method significantly. There are various commercially available technologies for sample preparation, including numerous variations of LLE, SPE, and SPME. However, these technologies all present significant deficiencies, including the inability to extract directly from complex samples such as whole milk. Instrumental analysis has been improved greatly in the last two decades but still is not applicable to complex samples without sample preparation. This work presents the theory of FPSE, including the synthesis of sol-gel sorbents, coating of FPSE cellulose substrates and the mechanism of retention. Original research data presented herein introduce a comprehensive view on possible applications of FPSE in forensic chemistry and otherwise. Five distinct FPSE-based methods were rigorously developed for analysis of targeted pollutant residues. These methods were validated and compare to leading methods published in peer-reviewed literature quite favorably. Four of the methods were coupled to HPLC-UV and designed for trace or ultra-trace analysis of PAHs, BTEX, substituted phenols and nitroaromatic explosives, respectively. An additional FPSE-based method was developed and validated for direct analysis of BPA and five estrogenic EDCs in commercially purchased whole milk. This latter was coupled to both HPLC-UV and HPLC(QQQ)-MS/MS. The applicability of FPSE(PTHF) media was also tested for screening of aqueous samples and subsequent storage of analytes on the sorbent. My study included simultaneous extraction of a mixture of eight forensically significant compounds with various physicochemical properties and effective storage of each compound in frozen and ambient conditions for 32 weeks. These findings suggest that the storage ability of FPSE media can be extended as long as necessary, which is very significant in forensic laboratories where evidence often needs to be stored in a costly manner that may not be as effective in maintaining the chemical composition of the sample.

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Mmualefe, Lesego Cecilia. "Sample preparation for pesticide analysis in water and sediments a case study of the Okavango Delta, Botswana." Thesis, Rhodes University, 2010. http://hdl.handle.net/10962/d1005006.

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This thesis presents a first ever extensive analysis of pesticides in water and sediments from the Okavango Delta, Botswana, employing green sample preparation techniques that require small volumes of organic solvents hence generating negligible volumes of organic solvent waste. Pesticides were extracted and pre-concentrated from water by solid phase extraction (SPE) and headspace solid phase microextraction (HS-SPME) while supercritical fluid extraction (SFE) and pressurized fluid extraction (PFE) were employed for sediments. Subsequent analysis was carried out on a gas chromatograph with electron capture detection and analytes were unequivocally confirmed by high resolution mass spectrometric detection. Hexachlorobenzene (HCB), trans-chlordane, 4,4′-DDD and 4,4′-DDE were detected after optimized HS-SPME in several water samples from the lower Delta at concentrations ranging from 2.4 to 61.4 μg L-1 that are much higher than the 0.1 μg L-1 maximum limit of individual organochlorine pesticides in drinking water set by the European Community Directive. The same samples were cleaned with ISOLUTE C18 SPE sorbent with an optimal acetone/n-hexane (1:1 v/v) mixture for the elution of analytes. No pesticides were detected after SPE clean-up and pre-concentration. HCB, aldrin and 4, 4‟-DDT were identified in sediments after SFE at concentration ranges of 1.1 - 30.3, 0.5 – 15.2 and 1.4 – 55.4 μg/g, respectively. There was an increase of pesticides concentrations in the direction of water flow from the Panhandle (point of entry) to the lower delta. DDE, fatty acids and phthalates were detected after PFE with optimized extraction solvent and temperature. The presence of DDT metabolites in the water and sediments from the Okavango Delta confirm historical exposure to the pesticide. However their cumulative concentration increase in the water-flow direction calls for further investigation of point sources for the long-term preservation of the Delta. The green sample preparation techniques and low toxicity solvents employed in this thesis are thus recommended for routine environmental monitoring exercises.

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Ahlgren, Joakim. "Organic Phosphorus Compounds in Aquatic Sediments : Analysis, Abundance and Effects." Doctoral thesis, Uppsala University, Analytical Chemistry, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6701.

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Phosphorus (P) is often the limiting nutrient in lacustrine and brackish eco-systems, and enhanced input of P into an aquatic system might therefore negatively impact the environment. Because modern waste water manage-ment have reduced external P input to surface waters, internal P loading from the sediment has become one of the main P sources to aquatic ecosys-tems, in which relatively unknown organic P compounds seem to be more active in P recycling than previously thought.

This thesis focus is on improving analysis methods for organic P com-pounds in lacustrine and brackish sediments, as well as determining which of these compounds might be degraded, mobilized and subsequently recycled to the water column and on what temporal scale this occur. In both lacustrine and brackish environments, the most labile P compound was pyrophosphate, followed by different phosphate diesters. Phosphate monoesters were the least labile organic P compounds and degraded the slowest with sediment depth. In regulated lakes, it was shown that pyrophosphate and polyphos-phate compound groups were most related to lake trophic status, thus indi-cating their involvement in P cycling. This thesis also indicates faster P turn-over in sediment from the brackish environment compared to sediment from the lacustrine environment.

A comparison of organic P extraction procedures showed that pre-extraction with EDTA, and NaOH as main extractant, was most efficient for total P extraction. Using buffered sodium dithionite (BD) as a pre-extractant and NaOH as main extractant was most efficient for extracting the presuma-bly most labile organic P compound groups, pyrophosphate and polyphos-phate. Furthermore, it was determined that organic P compounds associated with humic substances were more recalcitrant than other P compounds, that the BD step used in traditional P fractionation might extract phosphate monoesters, and that NMR is a statistically valid method for quantification of organic P compounds in sediment extracts.

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LIMA, ANA P. de S. "Avaliacao do impacto de uma atividade garimpeira no municipio de Cachoeira do Piria, Estado do Para." reponame:Repositório Institucional do IPEN, 2005. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11220.

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP

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杜國良 and Kwok-leung Dao. "Development of sample decomposition methods, preconcentration techniques and separation methods for high performance liquidchromatographic analysis of environmental pollutants and industrialwastes." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1994. http://hub.hku.hk/bib/B31233545.

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Carvalho, Lucas Sponton de. "Desenvolvimento e validação de métodos analíticos para avaliação da remoção de sulfonamidas no tratamento de águas residuárias em reatores biológicos de leito fixo." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-24022014-115605/.

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A presença de antibióticos no ambiente evidencia o problema do descarte inadequado de resíduos farmacêuticos e da ineficiência dos atuais sistemas de tratamento de resíduos. Como consequência a essa contaminação há a possibilidade de resistência microbiana e de outros efeitos nocivos, ainda não completamente compreendidos, sobre a fauna e flora aquática. O presente trabalho teve como um dos objetivos desenvolver métodos de preparo de amostra e análise para avaliar o potencial de um reator anaeróbio de leito fixo para a remoção de sulfonamidas de matrizes complexas, além de investigar possíveis resíduos dessa classe em diversos compartimentos ambientais da cidade de São Carlos. Para isso, métodos utilizando extração em fase sólida (SPE) e cromatografia líquida (LC) foram desenvolvidos em associação à análise por espectrometria de massas. Os resultados mostraram que o reator utilizado consegue remover satisfatoriamente o composto investigado, podendo ser, futuramente, uma alternativa aos tratamentos convencionais. Tais resultados foram obtidos a partir do desenvolvimento e validação de um método utilizando detecção por um analisador híbrido do tipo quadrupolo-tempo de voo (SPE-LC-QTOF). Outro método, baseado em SPE-LC-QTRAP (analisador híbrido quadrupolo-aprisionador de íons linear), foi validado visando mostrar que existe contaminação por sulfonamidas e trimetoprima em águas de córregos coletadas em algumas regiões da cidade. Tal objetivo foi atingindo, permitindo inclusive a comparação entre as figuras de mérito obtidas durante a validação dos métodos, que indicou que os analisadores (e os sistemas utilizados, em geral) possuem diferenças significativas que influem em parâmetros como o efeito de matriz, os limites de quantificação e a sensibilidade.
Paralelamente aos métodos convencionais, alternativas de preparo e análise que reduziam a necessidade de grandes volumes de amostra e solventes também foram desenvolvidos. A associação de técnicas miniaturizadas de preparo de amostra e análise permitiu que limites de detecção comparáveis aos dos métodos utilizando SPE fossem atingidos, utilizando, inclusive, o analisador do tipo tempo de voo. Dessa forma, um novo escopo de aplicações usufruindo das características deste último analisador poderá ser desenvolvido a partir da melhor pré-concentração proporcionada pelas estratégias de miniaturização estudadas.
The presence of antibiotics in the environment demonstrates the problem of improper drug disposal and inefficiency of the current water treatment systems. As a result of this contamination, there is the possibility of microbial resistance and other harmful effects, not totally understood, on the aquatic flora and fauna. The present study aimed to develop methods for sample preparation and analysis in order to evaluate the potential of an anaerobic fixed bed reactor for removing sulfonamides from complex matrices and, in addiction, to investigate the presence of this class of contaminants in various environmental compartments of São Carlos. For this, methods using solid phase extraction (SPE) and liquid chromatography (LC), were developed in association with the analysis by mass spectrometry . The results showed that the reactor used can satisfactorily remove the compound investigated and may be, in future, an alternative to conventional treatments. These results were obtained from the development and validation of a method based on solid phase extraction associated with liquid chromatography coupled to mass spectrometry using a hybrid quadrupole-time of flight (SPE-LC-QTOF) analyzer. Another method that was also developed and validated, based on SPE-LC-QTRAP (hybrid quadrupole-linear ion trap), was useful to show that there is contamination by sulfonamides and trimethoprim in water collected from rivers in some areas of the town. This objective was achieved, inclusive allowing the comparison between the figures of merit obtained during the methods validation, which indicated that the analyzers (and the systems used, in general) have significant differences which that affect parameters as matrix effect and quantification limits.
In parallel with the conventional methods, alternatives of sample preparation and analysis that reduced the need of large volumes of sample and solvent were also developed.
The association of miniaturized techniques of sample preparation and analysis allowed detection limits comparable to that of methods using SPE, even using small volumes of sample and solvent and a less sensitive mass analyzer. Thus, a new scope of applications, taking advantage of the characteristics of the QTOF, can be developed from the higher pre-concentration provided by the strategies studied in this work.

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Dao, Kwok-leung. "Development of sample decomposition methods, preconcentration techniques and separation methods for high performance liquid chromatographic analysis of environmental pollutants and industrial wastes /." [Hong Kong : University of Hong Kong], 1994. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13793871.

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SILVA, RITA de C. A. da. "Estudo da espécie garça-branca-grande Ardea alba (Linnaeus, 1758), para uso como bioindicadora da contaminação ambiental, na região metropolitana de São Paulo." reponame:Repositório Institucional do IPEN, 2013. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10548.

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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Cai, Beilei 1979. "Essays in health and environmental economics: Challenges in the empirical analysis of micro-level economic survey data." Thesis, University of Oregon, 2008. http://hdl.handle.net/1794/8505.

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xi, 108 p. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.
Micro-level survey data are widely used in applied economic research. This dissertation, which consists of three empirical papers, demonstrates challenges in empirical research using micro-level survey data, as well as some methods to accommodate these problems. Chapter II examines the effect of China's recent public health insurance reform on health utilization and health status. Chinese policy makers have been eager to identify how this reform, characterized by a substantial increase in out-of-pocket costs, has affected health care demand and health status. However, due to self-selection of individuals into the publicly insured group, the impact of the reform remains an unresolved issue. I employ a Heckman selection model in the context of difference-in-difference regression to accommodate the selection problem, and provide the first solid empirical evidence that the recent public health insurance reforms in China adversely affected both health care access and health status for publicly insured individuals. Chapter III examines the construct validity of a stated preference (SP) survey concerning climate change policy. Due to the fact that the SP survey method remains a controversial tool for benefit-cost analysis, every part of the survey deserves thorough examination to ensure the quality of the data. Using a random utility approach, I establish that there is a great deal of logical consistency between people's professed attitudes toward different payment vehicles and their subsequent choices among policies which vary in the incidence of their costs. Chapter IV employs the same survey data used in Chapter III, but demonstrates the potential for order effects stemming from prior attitude-elicitation questions. In addition, it considers the potential impact of these order effects on Willingness to Pay (WTP) estimates for climate change mitigation. I find the orderings of prior elicitation questions may change people's opinions toward various attributes of the different policies, and thereby increase or decrease their WTP by a substantial amount. Thus, this chapter emphasizes the significance of order effects in prior elicitation questions, and supports a call for diligence in using randomly ordered prior elicitation questions in stated preference surveys, to minimize inadvertent effects from any single arbitrary ordering.
Adviser: Trudy Ann Cameron

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Wright, Sarah E. "Sample Frequency, Duration, and Spatial Representation Considerations of Great Lakes Beach Sanitary Survey Data at Three Beaches in Racine, Wisconsin." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1416922217.

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OLIVEIRA, BRUNA R. de. "Avaliação dos metais ambientalmente disponíveis em amostras de sedimento de pontos de captação de água para abastecimento público de Palmas, TO." reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9940.

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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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Peterman, Paul Herbert. "Evaluation of Human Toenail as a Non-invasive Biomonitoring Matrix for Assessing Human Exposure to Environmental Organic Pollutants by Optimized Sample Prep and GC/HRMS Analysis." Thesis, University of Missouri - Columbia, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13877161.

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Human biomonitoring is an analytical challenge to find environmental organic chemicals of varying polarity, persistency, and potential toxicity in a suitable, ideally non-invasive matrix at ppb levels that are significantly above method blanks. Compared with more traditional matrices of adipose tissue, serum, and urine, toenail clippings samples are non-invasive, compact, can be shipped without refrigeration, stored indefinitely at room temperature, and processed without concerns for biohazards. With both hydrophilic and hydrophobic layers, toenails contain 1-2% lipid, which is several times higher than serum. Toenails grow slowly and are trimmed every 2-3 months, which offers the potential to integrate both chronic and pulsed episodic exposures. Using toenail samples (65 to 340 mg) donated from four individuals and an indoor house cat, the hypothesis that toenails are a suitable biomonitoring matrix was tested by analyzing for persistent pesticides, over 50 PCB congeners, moderately persistent PBDEs, and transient compounds of triclosan and bisphenol A by using GC/High Resolution MS (GC/HRMS) analysis and for unsuspected compounds using GC/full scan MS. Although not fully digested and dissolved, toenails averaged 1.22% lipid (sd 0.20%, n=10). Lipid was separated and determined using a new small single-use 2-g S-X3 gel permeation chromatography flash column with high purity nitrogen. Multiple toenail samples from one individual were collected for over a year for replicate analysis, p,p’- DDE averaged 0.82 ng/g-nail, sd 0.28, n=5 and 65.2 ng/g-lipid, sd 15.3, n=5 on lipid-adjusted basis. Trans-nonachlor averaged 3.08 ng/g-nail, sd 1.03, n=5; mean 254 ng/g-lipid, sd 97, n=5. PBDE 28 averaged 0.29 ng/g-nail, sd 0.10, n=5; mean 24.8 ng/g-lipid, sd 13.3, n=5. PBDE 85 averaged 0.25 ng/g-nail, sd 0.06, n=5; mean 20.8 ng/g-lipid, sd 6.2, n=5. PBDE 153 averaged 1.82 ng/g-nail, sd 0.51, n=6; mean 150 ng/g-lipid, sd 49.3, n=6. Most effectively biomonitored in toenails were normally transient triclosan (mean 58.3 ng/g-nail, sd 6.6, n=2), chlordanes, DDT, PBDEs, and PCBs including congeners with 2,5- or 2,3,6-chlorine substitution (PCBs 52, 49, 44, 70, 95, 101, 87, and 110), which are suspect neurotoxins, but are rarely found in extant serum biomonitoring data. Toenail soap wash samples indicated little (< 4%) or no exogenous contamination, except for the musks galaxolide and tonalide in most samples, which ranged up to 30%, likely from topical application. The one cat toenail sample had elevated concentrations of PBDEs and especially chlordanes. Unsuspected tentatively identified compounds included a UV Filter compound, octocrylene, a hydroxyl-methyl benzothiazole, and several compounds used in flavors or fragrances.

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COTRIM, MARYCEL E. B. "Avaliação da qualidade da água na bacia hidrográfica do Rio Ribeira de Iguape com vistas ao abastecimento público." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11568.

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

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Hidayanto, Eko. "Portable Elemental Analysis for Environmental Samples." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/66207.

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Wrenn, Douglas Harvey II. "Three Essays on Residential Land Development." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354563794.

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Cordeiro, Thiago Gomes. "Estudo da viabilidade da combinação da decomposição fotocatalítica de matéria orgânica com a geração de hidretos voláteis visando a determinação de arsênio por espectrometria de absorção atômica." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-01102014-093900/.

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Propõe-se, pela primeira vez, a associação do tratamento fotocatalítico de amostra, direcionado à degradação e/ou eliminação de interferentes orgânicos, com a separação analito/matriz via geração de hidretos voláteis seguida de determinação por espectrometria de absorção atômica (HG-AAS). O fotocatalisador TiO2 (P-25) foi utilizado sempre em suspensão na amostra, e como fonte de radiação UV empregou-se lâmpada de mercúrio. Duas geometrias de reator fotocatalítico foram examinadas: irradiação estacionária de amostras contidas em cubetas de quartzo (3,5 mL); e irradiação em reator tubular constituído de bobina de Teflon montada em torno da lâmpada. Para avaliar a eficiência do tratamento sob diferentes condições, utilizou-se inicialmente o sistema-modelo Cd(II)-EDTA, com detecção do Cd(II) não quelado por voltametria de pulso diferencial em eletrodo de gota pendente de mercúrio, sabidamente não influenciada pelo TiO2 em suspensão. Nos estudos com HG-AAS, focalizou-se a aplicação do tratamento fotocatalítico à decomposição da arsenobetaína (Asb), um composto modelo interessante por ser refratário aos tratamentos convencionais (micro-ondas + digestão ácida). As condições selecionadas para a etapa de HG-AAS foram: concentração de HCl, 3 mol.L-1, concentração de NaBH4, 1% m/v em NaOH 0,1 mol.L-1, volume de amostra, 0,10 mL e temperatura do atomizador de tubo de quartzo, 980 °C. Nessas condições, as curvas de calibração obtidas por HG-AAS para As(III) e As(V) na faixa de 0,020 a 0,100 mg.L-1 (20 a 100 ppb) apresentaram linearidade e sensibilidade próximas, indicando eficiência de formação similares, característica esta favorável à quantificação total de arsênio em aplicações futuras a amostra reais. Estudos preliminares mostraram que a taxa de recuperação do arsênio é maior no tratamento fotocatalítico realizado em meio alcalino, (pH=12) em razão da menor tendência à adsorção de arsênio em TiO2 nesse meio frente ao neutro e ácido. Parâmetros como o tempo de irradiação, concentração do fotocatalisador e de Asb, além da influência de O2 molecular como scavenger de elétrons também foram investigados. Nas condições selecionadas, partindo-se de uma solução de Asb 0,075 mg.L-1 em arsênio, alcançou-se recuperação aproximada de 80% mediante irradiação por 15 minutos e de 100% após 45 minutos. A decomposição da Asb pelo método fotocatalítico proposto foi confirmada por espectrometria de massa com ionização por electrospray e estudos adicionais poderão revelar se as espécies de arsênio envolvidas na geração da arsina encontram-se completamente mineralizadas.
The combination of photocatalytic sample preparation, aiming degradation of organic interferences, with analyte/matrix separation by generation of volatile hydrides followed by atomic absorption spectrometric determination (HG-AAS) is proposed for the first time in this work, mainly devoted to the investigation of total arsenic analysis. A mercury lamp served as source of UV-radiation and the photocatalyst, TiO2 (P25), was used as a suspension in the sample solution. Two geometries of photocatalytic reactor were examined: stationary irradiation of a set of samples contained in 3.5 mL quartz cuvettes (preferred one for the present application) and stopped-flow irradiation of a sample in a tubular reactor consisting of a Teflon tube coiled around the lamp. Evaluation of the digestion efficiency of the reactors under different conditions was made with help of the model system Cd(II)-EDTA, with detection of the unchelated Cd(II) by differential pulse voltammetry with the hanging mercury drop electrode, known to work in the presence of TiO2 suspension. The subsequent studies in combination with HG-AAS focused on the photocatalytic degradation of arsenobetaine (Asb), chosen as a model because it is particularly resistant to conventional treatments (microwave + acid digestion). The following conditions were established for the HG-AAS step: HCl concentration (3 mol.L-1) and NaBH4 concentration (1% m/v in NaOH 0,1 mol.L-1), sample volume (0.10 mL) and atomization temperature (980 °C). Calibration curves for As (III) and As (V) by HG-AAS in the range of 0,020 to 0,100 mg.L-1 (20 a 100 ppb) conveyed in slope and linearity, indicating the same efficiency of arsine formation from both species, favoring the total quantification of arsenic in the sample. Alkaline medium (pH=12) was preferred for the photocatalytic digestion because recoveries of arsenic were better than in neutral or acidic medium, possibly due to lower losses by adsorption of arsenic species on TiO2. The effects of parameters such as irradiation time, concentration of the photocatalyst and of arsenobetaine, as well as the influence of molecular O2 as an electron scavenger were investigated. Under selected conditions and for a starting solution of 0,075 mg.L-1 Asb an arsenic recovery of 80% approximately was obtained after 15 minutes of irradiation while full recovery required 45 minutes. The decomposition of the Asb molecule after irradiation was confirmed by electrospray mass spectrometry and a further study may reveal if the arsenic species involved in the arsine generation are fully mineralized ones.

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Taebunpakul, Sutthinun. "Arsenic speciation analysis in food-related and environmental samples." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/6858.

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Metallomics approaches based on the combined use of elemental and molecular mass spectrometry for arsenic speciation analysis in phytoremediating plants, marine algae, cut tobacco and cigarette smoke total particulate matter have been developed. Size-exclusion chromatography (SEC)-ICP-MS is proposed to use as a powerful tool for selecting both the appropriate extractant as well as optimum extraction conditions. Comparative SEC-ICP-MS As profiles and total As concentrations in the extracts were used to identify the optimum condition for As speciation studies as a compromise between extraction efficiency and preservation of compound identity. Methodologies have been developed to gain a better grasp of the factors involved in the uptake and distribution of As in the hydroponically grown Arabidopsis thaliana. The effect of the presence of Se on the As and Hg incorporated into the leaves was investigated here for the first time; Se in the growing media was found not to affect As and Hg concentrations in the leaves. Results also revealed the presence of small amounts of As-PC3, As-PC4 and As-PC5 complexes in the leaves, which were characterized by ESI-Orbitrap MS to minimize ambiguity in species identification. The application of an in vitro dialysis method for predicting the As bioaccessibility in selected edible marine algae, was investigated here for the first time. Results showed low As dialyzability (10-20%) and no transformation of As species, primarily arsenosugars, observed following in vitro gastrointestinal digestion. Knowledge of the distribution of arsenic species in cut tobacco, obtained by sequential extraction, provides an insight into the transformation of arsenic species during the combustion process when the cigarette is burnt. The combustion of organic compounds present in tobacco resulted in the change of redox state and As-species distribution in tobacco smoke. Both the hyphenated MS and XANES techniques were used to obtain information about arsenic speciation in smoke condensates. The results showed that the tobacco smoke contained a mixture of As(III) and As(V); As(III) being found as arsenite and, possibly, thio-arsenite by HPLC-ICP-MS. The reduction of As(V) to As(III) during dynamic cigarette smoke formation can be explained by the overall smoke redox properties in accordance with the cigarette combustion process.

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Zanin, Gimel Roberto. "Importância do mapeamento de habitats e do planejamento amostral no processo de avaliação de impactos ambientais sobre comunidades bentônicas de fundos não consolidados." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/21/21134/tde-15042014-150016/.

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O presente estudo realizou uma análise crítica do planejamento amostral de comunidades bentônicas de substratos inconsolidados. Para tal, foram realizadas análises de custo-benefício dos desenhos amostrais estratificados e não estratificados em ambiente computacional, através das estimativas de exatidão e precisão da amostragem. Os desenhos estratificados apresentaram melhor custo-benefício (mais exatos) do que os não estratificados, sendo que o desenho estratificado-hierarquizado foi considerado o mais custo-eficiente, com melhor precisão em comparação ao estratificado-aleatorizado. Além disso, desenho e esforço amostrais, descritor de comunidade, poder estatístico e complexidade da comunidade bentônica influenciaram a precisão da amostragem. Os conceitos obtidos foram testados em conjunto de dados reais, coletados na Enseada de Caraguatatuba (SP), com vistas à sua aplicação no âmbito do licenciamento ambiental. As tendências observadas para dados reais convergiram com as obtidas nos cenários computacionais. Quanto à aplicação no licenciamento ambiental, constatou-se que diferentes setores da sociedade divergem quanto ao número mínimo de amostras necessário para alcançar níveis adequados de precisão na avaliação de impactos ambientais. Os ambientalistas foram os mais conservadores e a comunidade científica os menos conservadores. Ainda, tanto no cenário virtual quanto no real, uma precisão de 10% resultou em esforços amostrais viáveis financeira e logisticamente, assegurando poder estatístico de 90% no teste de hipóteses
This study performed a critical analysis of the sampling planning of benthic communities in unconsolidated substrates. Cost-benefit analysis of the stratified and non-stratified sample designs were conducted in computational environment, through estimates of sampling accuracy and precision. Thestratified designs presented better cost-benefit results than the non-stratified ones, and the stratified-hierarchical design was considered the most costefficient, with better precision compared to the stratified-randomized. In addition, sampling design and effort, community descriptor, statistical power and complexity of the benthic community influenced sampling precision. These concepts were applied to real data sets collected in Caraguatatuba Bay (SP), with perspectives to its application in environmental licensing. The observed trends for real data converged with the computational scenarios. Regarding its applications for environmental licensing, it was observed that different groups in the society disagreed about the minimum number of samples necessary to achieve adequate precision in environmental impact assessment. Environmentalists were the most conservative group, while members of the scientific community were the least conservative one. Finally, both in real and virtual scenarios, a precision of 10% resulted in sampling efforts which were financially and logistically feasible, assuring a statistical power of 90% in hypothesis testing

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24

Garcia, Ramon. "Microwave-assisted decomposition of environmental samples, and the analysis of plutonium and radiostrontium." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/17233.

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25

吳祖成 and Zucheng Wu. "Development of acillary techniques for chromatographic analysis of trace organic pollutants in environmental samples." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31236327.

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26

Dahlin, Johan. "3D Modeling of Indoor Environments." Thesis, Linköpings universitet, Reglerteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-93999.

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With the aid of modern sensors it is possible to create models of buildings. These sensorstypically generate 3D point clouds and in order to increase interpretability and usability,these point clouds are often translated into 3D models.In this thesis a way of translating a 3D point cloud into a 3D model is presented. The basicfunctionality is implemented using Matlab. The geometric model consists of floors, wallsand ceilings. In addition, doors and windows are automatically identified and integrated intothe model. The resulting model also has an explicit representation of the topology betweenentities of the model. The topology is represented as a graph, and to do this GraphML isused. The graph is opened in a graph editing program called yEd.The result is a 3D model that can be plotted in Matlab and a graph describing the connectivitybetween entities. The GraphML file is automatically generated in Matlab. An interfacebetween Matlab and yEd allows the user to choose which rooms should be plotted.

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Jantzi, Sarah C. "Elemental Analysis and Forensic Comparison of Soils by Laser-Induced Breakdown Spectroscopy (LIBS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/967.

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The elemental analysis of soil is useful in forensic and environmental sciences. Methods were developed and optimized for two laser-based multi-element analysis techniques: laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser-induced breakdown spectroscopy (LIBS). This work represents the first use of a 266 nm laser for forensic soil analysis by LIBS. Sample preparation methods were developed and optimized for a variety of sample types, including pellets for large bulk soil specimens (470 mg) and sediment-laden filters (47 mg), and tape-mounting for small transfer evidence specimens (10 mg). Analytical performance for sediment filter pellets and tape-mounted soils was similar to that achieved with bulk pellets. An inter-laboratory comparison exercise was designed to evaluate the performance of the LA-ICP-MS and LIBS methods, as well as for micro X-ray fluorescence (μXRF), across multiple laboratories. Limits of detection (LODs) were 0.01-23 ppm for LA-ICP-MS, 0.25-574 ppm for LIBS, 16-4400 ppm for µXRF, and well below the levels normally seen in soils. Good intra-laboratory precision (≤ 6 % relative standard deviation (RSD) for LA-ICP-MS; ≤ 8 % for µXRF; ≤ 17 % for LIBS) and inter-laboratory precision (≤ 19 % for LA-ICP-MS; ≤ 25 % for µXRF) were achieved for most elements, which is encouraging for a first inter-laboratory exercise. While LIBS generally has higher LODs and RSDs than LA-ICP-MS, both were capable of generating good quality multi-element data sufficient for discrimination purposes. Multivariate methods using principal components analysis (PCA) and linear discriminant analysis (LDA) were developed for discriminations of soils from different sources. Specimens from different sites that were indistinguishable by color alone were discriminated by elemental analysis. Correct classification rates of 94.5 % or better were achieved in a simulated forensic discrimination of three similar sites for both LIBS and LA-ICP-MS. Results for tape-mounted specimens were nearly identical to those achieved with pellets. Methods were tested on soils from USA, Canada and Tanzania. Within-site heterogeneity was site-specific. Elemental differences were greatest for specimens separated by large distances, even within the same lithology. Elemental profiles can be used to discriminate soils from different locations and narrow down locations even when mineralogy is similar.

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Lyn, Jennifer A. "Optimising uncertainty from sampling and analysis of foods and environmental samples." Thesis, University of Sussex, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270732.

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Brown, Jessica Elise. "Assessment of Similarity in Chemically Complex Samples." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1954.

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Concern within the public health community is mounting regarding what some deem as "candy-flavored tobacco". A recent study by King et al. (2014) found that >40% of middle and high school student smokers use flavored cigarettes or flavored little cigars. This study investigated the validity of the "candy-flavored tobacco" designation by comparing flavor profiles of 18 flavored tobacco products with 15 candy and Kool-Aid products using gas chromatography mass spectrometry (GC/MS). Significant compositional overlap was found; nearly 75% of the compounds detected were present in at least one flavored tobacco and one candy or Kool-Aid product. Benzaldehyde and or benzyl alcohol were measured in cherry candies, Kool-Aid and tobacco. Similar levels of benzaldehyde were measured in the cherry Kool-Aid and wild cherry Cheyenne cigars at 3338 ± 623 and 3937 ± 251 μg/serving. Methyl anthranilate, 1-hexanol, [lowercase gamma]-decalactone, and raspberry ketone were found in all grape, apple, peach and berry products, respectively. Vanillin and or ethyl vanillin were constituents of all flavored tobacco products analyzed. Many flavorants, such as limonene, are also volatilizable biogenic organic compounds (VBOCs). A more comprehensive understanding of the identities and properties of VBOCs, precursors to secondary organic aerosol (SOA), would support air quality and climate change research and management. Our knowledge is limited by extreme compositional diversity within the VBOC class. Only recently have techniques such as two-dimensional gas chromatography time of flight mass spectrometry (GCxGC/TOFMS) been employed, and the complexity of the data poses analysis challenges. To address this, agglomerative hierarchical cluster analysis (HCA) was performed on data generated by GCxGC/TOFMS analysis of air samples collected during the Particle Investigations at a Northern Ozarks Tower: NOx, Oxidant, Isoprene Research (PINOT NOIR) study. HCA resulted in the assignment of 204 compounds into 27 clusters: these clusters were grouped into 4 distinct types making the data significantly more manageable. The assignment of a cluster to a type was mostly based on the frequency with which compounds appeared in samples. Type I clusters contained compounds that were present in only one sample, suggesting meteorological influence.

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Zhang, Xin. "Application of chemometrics to hyperspectral imaging analysis of environmental and agricultural samples." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/301275.

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This Thesis deals with the resolution of hyperspectral imaging data by using chemometric methods, in particular by using appropriate data pretreatment methods and by using Multivariate Curve Resolution (MCR) methods. The main contribution of the present Thesis is the study and implementation of the MCR-ALS (Multivariate Curve Resolution Alternating Least Squares) method for the resolution of hyperspectral images, collected by remote sensing (airborne or space borne Earth observation instrument) and by micro-spectroscopy imaging. Specifically, in this Thesis work, we explore the combination of chemometric and hyperspectral imaging methods for the resolution of spectra (signatures) and spatial distribution maps of the chemical constituents of a sample. The ultimate goal of this study is to improve the analysis and interpretation of hyperspectral imaging data by taking advantage of different chemometric powerful tools. Local rank/selectivity properties describing the spatial information of spectroscopic images can be used as a constraint to increase the performance of MCR methods significantly, decreasing rotation ambiguity uncertainties. Different multivariate resolution methods were compared, such as MCR-ALS, Principal Component Analysis (PCA), and Minimum Volume Simplex Analysis (MVSA), Multivariate Curve Resolution-Function Minimization (MCR-FMIN), MCR-BANDS and FAC-PACK. All these approaches have been used for the evaluation of the extension of rotation ambiguities remaining in the results after their application. Several hyperspectral images provided by standard and widely used instruments such as NASA’s Airborne Visible Infra-Red Imaging Spectrometer (AVIRIS), Raman hyperspectral imaging Spectrometer, and Infrared hyperspectral imaging Spectrometer have been used as example of data sets to test the different methods, in particular to test the MCR-ALS method. The results obtained in this Thesis show that MCR-ALS method can be successfully used for hyperspectral image resolution purposes. The spectra signatures of the pure constituents present in hyperspectral images and their concentration distribution at a pixel level can be estimated. Constituents identification can be performed using the resolved pure spectra signatures and comparing them to reference spectra from spectral libraries or from experimental spectra of reference samples. Application of image data pretreatment methods reduce significantly the presence of strong fluorescence background in Raman hyperspectral images. In contrast, infrared hyperspectral imaging is not affected by fluorescence. Kramers-Kronig transform enables to calculate absorption spectra in case only reflectance spectra can be measured for infrared spectra. The extent of rotation ambiguity associated to MCR-ALS and other resolution methods can be rather high when they are applied for hyperspectral image resolution with high noise. The correct resolution of hyperspectral images can only be guaranteed if additional constraints are applied, such as those providing information about the local rank properties of the image, i.e. about the presence or absence of the different constituents (components) in the image pixels. Only in this way it is possible to increase the reliability of the solutions provided by MCR methods and decrease the uncertainties associated to them. Appropriate use of local rank and selectivity constraints can improve significantly the quality of the pure spectra (signatures) and of the constituent distribution maps resolved by MCR-ALS analysis of hyperspectral images in remote sensing studies. Use of correlation coefficients between selected spectra and image pixel spectra is shown to provide an alternative way for the application of the selectivity constraint in hyperspectral images for the first time. This alternative method resulted to be satisfactory when pure pixels exist. MCR-BANDS method can be used to get estimations of the extension of rotation ambiguities in MCR resolved results. The Area of Feasible Solutions represents feasible solutions geometrically. The range of rotation ambiguity calculated by MCR-BANDS and AFS are in agreement. MCR-ALS with the trilinearity constraint is an effective way to characterize and resolve Excitation-Emission Matrix fluorescence spectra (EEM).
Esta Tesis trata de la resolución de datos de imágenes hiperespectrales utilizando métodos quimiométricos, en particular mediante el uso de métodos de pretratamiento de datos y utilizando métodos de resolución multivariante de curvas (MCR). La principal contribución de la presente Tesis es el estudio y la aplicación del método MCR-ALS (resolución multivariante de curvas mediante mínimos cuadrados alternados) para la resolución de imágenes hiperespectrales, adquiridas mediante técnicas de teledetección y mediante técnicas de micro-espectroscopia. Específicamente, en el trabajo de esta Tesis, se explora la combinación de los métodos quimiométricos y de los métodos de análisis de imágenes hiperespectrales, para la resolución de los espectros (firmas) y de los mapas de distribución de los componentes químicos de la muestra. El objetivo final de este estudio es mejorar el análisis y la interpretación de los datos de imágenes hiperespectrales mediante el aprovechamiento de diferentes herramientas quimiométricas poderosas. La detección del rango local y las propiedades de selectividad que describen la información espacial de los componentes presentes en las imágenes espectroscópicas. Se han comparado diferentes métodos de resolución, tales como MCR-ALS, MVSA (Mínimo Volumen Simplex Análisis), PCA (Análisis de Componentes Principales), y MCR-FMIN. Los métodos MCR-BANDS y FAC-PACK se han utilizado para la evaluación de la extensión de las ambigüedades rotacionales existentes en los resultados después de la aplicación de estos métodos de resolución multivariante. En esta Tesis se han analizado diversos conjuntos de datos compuestos por varias imágenes hiperespectrales proporcionadas por instrumentos estándar tales como el espectrómetro de imágenes hiperespectrales en el visible y en el infrarrojo AVIRIS de la NASA, y diversos espectrómetros de imágenes hiperespectrales Raman y infrarrojo de laboratorio. La eficacia del procedimiento MCR-ALS se ilustra proporcionando comparaciones exhaustivas con otros métodos de resolución de mezclas espectrales a partir de conjuntos de datos hiperespectrales simulados y reales.

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Skutas, Jorie L. "Microbial and Genomic Analysis of Environmental Samples in Search of Pathogenic Salmonella." NSUWorks, 2017. http://nsuworks.nova.edu/occ_stuetd/461.

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Salmonellosis or “food poisoning” is a foodborne infection brought on by the pathogen Salmonella from the ingestion of the bacterium on contaminated foods such as vegetables. Infection from Salmonella leads to the highest incidence of hospitalizations and deaths each year, compared to any other bacterial foodborne illness. South Florida is the second largest agricultural winter vegetable producer in the United States, and contamination of vegetables is often observed in preharvest practices. A hardy bacterium, Salmonella, has been shown to live up to 6 weeks in soil and water up to 42°C without a host. The Florida Everglades is a tropical wetland that plays a large role in South Florida’s watershed. It can be divided into agricultural, conservation, and urban areas that connect Lake Okeechobee to Florida Bay by canals, swamps, and rivers. Inland canals tightly regulate water levels in South Florida as a means of flood control for residential and agricultural land. With the influences of anthropomorphic run off from agricultural and urban use, we hypothesized that microbial communities would significantly differ between three select sites in western (Collier county) versus three sites in more urban eastern Florida (Broward county): natural standing water, manmade drainage canal in agricultural areas, and manmade drainage canals in urban areas. We also hypothesized that pathogenic like Salmonella would be present in these habitats. Deep sequencing and ecological genetics analyses of the 16s rRNA V4 region yielded a total of 163,320 unique bacterial OTUs from a total of 139 samples collected monthly for one year in 2015 and part of 2016. Salmonella is not considered an abundant taxon within the microbial population. With the knowledge that Salmonella resides within the microbial population isolates were cultured from soil and water samples that were taken monthly from each site using a modified version of the Food and Drug Administration Bacterial Analytical Methods manual (FDA-BAM). The culturing resulted in 234 isolates obtained and 31 different serovars of Salmonella. Culturing showed that Salmonella favored months with high standing water and high-water temperatures that would lead to the ideal environment for survival. The most commonly occurring isolates within the sample set are those associated with agricultural animals. Though Salmonella may be a rare taxon within the microbial population given the correct environmental conditions such as warm temperatures it is possible to observe Salmonella year round within the South Florida environment.

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Gosland, Raymond Montgomery. "Developments in the analysis of environmental samples by ICP-MS and ETAAS." Thesis, University of Strathclyde, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282783.

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MATSUBARA, TASSIANE C. M. "Estudo sobre a determinação de antimônio em amostras ambientais pelo método de análise por ativação com nêutrons. Validação da metodologia e determinação da incerteza da medição." reponame:Repositório Institucional do IPEN, 2011. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10042.

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Made available in DSpace on 2014-10-09T12:34:07Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T14:00:09Z (GMT). No. of bitstreams: 0
Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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Wu, Zucheng. "Development of acillary techniques for chromatographic analysis of trace organic pollutants in environmental samples /." Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19667188.

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35

麥麗玲 and Lai-ling Josephine Mak. "Determination of pesticides in environmental and food samples by capillary electrophoresis and electroanalytical methods." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31243459.

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Bhowmick, Subhamoy. "Arsenic and its speciation analysis in biological and environmental samples using ICP techniques." Doctoral thesis, Universitat de Girona, 2013. http://hdl.handle.net/10803/125307.

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Arsenic (As) is one of the common cancers causing contaminant in groundwater of West Bengal, India along with other regions of the world. Scientists believe that As contamination in groundwater of these region are because of the reductive dissolution of iron oxyhydroxide and the oxidation of organic matter. However, our research shows that a combination of carbonate mineral dissolution and the reduction of iron oxyhydroxides accounts for the high As concentration in groundwater. Thus the people of this region are exposed daily to high levels of As through various pathways. Our study on saliva shows that this biofluid is a good biomarker of As exposure. Moreover, by measuring the various forms of As in saliva, individual susceptibility to arsenic related diseases can be understood. Lastly, we propose nano Zero Valent iron doped onto montmorillonite as an effective material to reduce high levels of As in water quickly and efficiently
L'arsènic (As) és un dels contaminants cancerígens més comuns en les aigües subterrànies de Bengala Occidental, Índia, així com d’altres regions. Els científics creuen que la contaminació en arsènic en l'aigua subterrània d'aquesta regió és deguda a la dissolució reductiva dels oxihidròxids de ferro i a l'oxidació de la matèria orgànica. No obstant, la nostra investigació mostra que una combinació de la dissolució mineral de carbonat i la reducció dels oxihidròxids de ferro en són la causa. Com a conseqüència la població d'aquesta regió estan exposats a nivells alts d'As. El nostre estudi mostra que la saliva és un bon biomarcador d'exposició a l’arsènic. A més, mitjançant la determinació de l’especiació d’As en saliva es pot comprendre la susceptibilitat individual a malalties relacionades amb aquest element. Finalment, proposem la utilització de montmorillonita dopada amb nanopartícules de ferro metàl·lic com un material eficaç per reduir els alts nivells d'As en l'aigua

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Ellis, Jenny. "Elemental speciation analysis of metals, phosphorus and sulfur exploring environmental and biological samples /." Cincinnati, Ohio : University of Cincinnati, 2007. http://www.ohiolink.edu/etd/view.cgi?ucin1196104876.

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Thesis (Ph. D.)--University of Cincinnati, 2007.
Advisor: Joseph A. Caruso. Title from electronic thesis title page (viewed Feb. 6, 2008). Keywords: ICP-MS; Phosporus; Sulfur; Elemental Speciation; Mass spectrometry; Fire retardants; Phosphopeptides. Includes abstract. Includes bibliographical references.

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Worrasettapong, Watcharapong. "Ultratrace analysis and speciation studies on trace elements in environmental and biological samples." Thesis, University of Sheffield, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269381.

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Silwana, Bongiwe. "Graphene supported antimony nanoparticles on carbon electrodes for stripping analysis of environmental samples." University of the Western Cape, 2015. http://hdl.handle.net/11394/5141.

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>Magister Scientiae - MSc
Platinum Group Metals (PGMs), particularly palladium (Pd), platinum (Pt) and rhodium (Rh) have been identified as pollutants in the environment due to their increased use in catalytic converters and mining in South Africa (as well as worldwide). Joining the continuous efforts to alleviate this dilemma, a new electrochemical sensor based on a nanoparticle film transducer has been developed to assess the level of these metals in the environment. The main goal of this study was to exploit the capabilities of nanostructured material for the development and application of an adsorptive stripping voltammetric method for reliable quantification of PGMs in environmental samples. In the study reported in this thesis, glassy carbon electrode (GCE) and screen-printed carbon electrode (SPCE) surfaces were modified with conducting films of nanostructured reduced graphene oxide-antimony nanoparticles (rGO-SbNPs) for application as electrochemical sensors. The rGO-SbNPs nanocomposite was prepared by Hummer`s synthesis of antimony nanoparticles in reaction medium containing reduced graphene oxide. Sensors were constructed by drop coating of the surfaces of the carbon electrodes with rGO-SbNPs films followed by air-drying. The nanocomposite material was characterised by: scanning and transmission electron miscroscopies; FTIR, UV-Vis and Ramanspectrosocopies; dc voltammetry; and electrochemical impedance spectroscopy. The real surface area of both electrodes were studied and estimated to be 1.66 × 10⁶ mol cm⁻² and 4.09 × 10³ mol cm⁻² for SPCE/rGO-SbNPs and GCE/rGO-SbNPs, respectively. The film thickness was also evaluated and estimated to be 0.36 cm and 1.69 × 10⁻⁶ cm for SPCE/rGO-SbNPs and GCE/rGO-SbNPs, respectively. Referring to these results, the SPCE/rGO-SbNPs sensor had a better sensitivity than the GCE/rGO-SbNPs sensor. The electroanalytical properties of the PGMs were first studied by cyclic voltammetry followed by indepth stripping voltammetric analysis. The development of the stripping voltammetry methodology involved the optimisation of experimental conditions such as selection of adequate supporting electrolyte, choice of pH and /or concentration of supporting electrolytes, deposition potential, deposition time, stirring conditions. The detection of Pd(II), Pt(II) and Rh(III) in environmental samples were performed SPCE/rGO-SbNPs and GCE/rGO-SbNPs at the optimised experimental conditions For the GCE/rGO-SbNPs sensor, the detection limit was found to be 0.45, 0.49 and 0.49 pg L⁻¹ (S/N = 3) for Pd(II), Pt(II) and Rh(III), respectively. For the SPCE/rGO-SbNPs sensor, the detection limit was found to be 0.42, 0.26 and 0.34 pg L⁻¹ (S/N = 3) for Pd(II), Pt(II) and Rh(III), respectively. The proposed adsorptive differential pulse cathodic stripping voltammetric (AdDPCSV) method was found to be sensitive, accurate, precise, fast and robust for the determination of PGMs in soil and dust samples. The simultaneous determination of PGMs was also investigated with promising results obtained. The AdDPCSV sensor performance was compared with that of inductive coupled plasma mass spectroscopy (ICP-MS) for the determination of PGM ions in soil and dust samples. It was found that though the metals could be determined by ICP-MS technique, it was limited from the standpoints of sensitivity, ease of operation and versatility compared to the AdDPCSV sensor. This study has show cased the successful construction and application of novel SPCE/rGO-SbNPs and GCE/rGO-SbNPs AdDPCSV sensors forthe determination of PGMs in environmental samples (specifically roadside dust and soil samples). The study provides a promising analytical tool for monitoring PGMs pollutants that are produced by automobiles and transported in the environment.

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ELLIS, JENNY L. "ELEMENTAL SPECIATION ANALYSIS OF METALS, PHOSPHORUS AND SULFUR: EXPLORING ENVIRONMENTAL AND BIOLOGICAL SAMPLES." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1196104876.

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41

Tsai, Yeng-Chieh. "The application of two-dimensional genomic DNA nylon matrix for environmental samples analysis." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 67 p, 2009. http://proquest.umi.com/pqdweb?did=1654501591&sid=1&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Yu, Zhao. "Syntheses and Sensing Applications of Modified Noble Metal-containing Nanoparticles." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1623251284619434.

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43

Wilson, Walter. "Novel Developments on the Extraction and Analysis of Polycyclic Aromatic Hydrocarbons in Environmental Samples." Doctoral diss., University of Central Florida, 2014. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/6384.

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This dissertation focuses on the development of analytical methodology for the analysis of polycyclic aromatic hydrocarbons (PAHs) in water samples. Chemical analysis of PAHs is of great environmental and toxicological importance. Many of them are highly suspect as etiological agents in human cancer. Among the hundreds of PAHs present in the environment, the U.S. Environmental Protection Agency (EPA) lists sixteen as "Consent Decree" priority pollutants. Their routine monitoring in environmental samples is recommended to prevent human contamination risks. A primary route of human exposure to PAHs is the ingestion of contaminated water. The rather low PAH concentrations in water samples make the analysis of the sixteen priority pollutants particularly challenging. Current EPA methodology follows the classical pattern of sample extraction and chromatographic analysis. The method of choice for PAHs extraction and pre-concentration is solid-phase extraction (SPE). PAHs determination is carried out via high-performance liquid chromatography (HPLC) or gas chromatography/mass spectrometry (GC/MS). When HPLC is applied to highly complex samples, EPA recommends the use of GC/MS to verify compound identification and to check peak-purity of HPLC fractions. Although EPA methodology provides reliable data, the routine monitoring of numerous samples via fast, cost effective and environmentally friendly methods remains an analytical challenge. Typically, 1 L of water is processed through the SPE device in approximately 1 h. The rather large water volume and long sample processing time are recommended to reach detectable concentrations and quantitative removal of PAHs from water samples. Chromatographic elution times of 30 – 60 min are typical and standards must be run periodically to verify retention times. If concentrations of targeted PAHs are found to lie outside the detector's response range, the sample must be diluted (or concentrated), and the process repeated. In order to prevent environmental risks and human contamination, the routine monitoring of the sixteen EPA-PAHs is not sufficient anymore. Recent toxicological studies attribute a significant portion of the biological activity of PAH contaminated samples to the presence of high molecular weight (HMW) PAHs, i.e. PAHs with MW ? 300. Because the carcinogenic properties of HMW-PAHs differ significantly from isomer to isomer, it is of paramount importance to determine the most toxic isomers even if they are present at much lower concentrations than their less toxic isomers. Unfortunately, established methodology cannot always meet the challenge of specifically analyzing HMW-PAHs at the low concentration levels of environmental samples. The main problems that confront classic methodology arise from the relatively low concentration levels and the large number of structural isomers with very similar elution times and similar, possibly even virtually identical, fragmentation patterns. This dissertation summarizes significant improvements on various fronts. Its first original component deals with the unambiguous determination of four HMW-PAHs via laser-excited time-resolved Shpol'skii spectroscopy (LETRSS) without previous chromatographic separation. The second original component is the improvement of a relatively new PAH extraction method - solid-phase nanoextraction (SPNE) - which uses gold nanoparticles as extracting material for PAHs. The advantages of the improved SPNE procedure are demonstrated for the analysis of EPA-PAHs and HMW-PAHs in water samples via GC/MS and LETRSS, respectively.
Ph.D.
Doctorate
Chemistry
Sciences
Chemistry

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Marshall, Lisa-Jane R. "Chemical analysis of archaeologically important samples from waterlogged, temperate and arid environments." Thesis, University of Reading, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493953.

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The overall aim of this project was to integrate chemical and archaeological techniques by the study of a number of specific individual cases from temperate, semi-arid and waterlogged sites. Samples taken from a Roman road profile at the temperate site of Silchester were found to be composed of chert and kaolinite. No phosphate, an indicator for human/animal activity was identified. Analysis of the metal content of the road samples showed high levels of iron in all layers with the highest percentage found in the orange layer. The iron may be present as an iron silicate which is found around areas where metalworking (especially ironworking) took place.

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Yeung, Wai Yin. "Environmental concentrations, toxicology, and development of new methods for extraction and mass balance analysis of perfluorinated compounds in environmental samples /." access full-text access abstract and table of contents, 2009. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?phd-bch-b2374960xf.pdf.

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Thesis (Ph.D.)--City University of Hong Kong, 2009.
"Submitted to Department of Biology and Chemistry in partial fulfillment of the requirements for the degree of Doctor of Philosophy." Includes bibliographical references (leaves 211-239)

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McClean, Jennifer Natalie. "Novel isothermal PCR methodologies for the selective detection and analysis of microorganisms in environmental samples." Thesis, Queen's University Belfast, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557957.

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SUMMARY (To be printed on this form) Phosphoramidite derivatives of a nucleoside analogue bearing photoswitchable ortho, meta and para-azobenzene moieties were synthesized and used to incorporate the photoswitchable azobenzene group proximal to the 5' and 3' ends of deoxyoligonucIeotide primers (12mers) of the glyceraldehydes-3-phosphate dehydrogenase (GAPDH) gene. The photochemical E~Z isomerisation of azobenzene appended primers was investigated by UV/vis spectroscopy and RP-HPLC. Melting studies were also performed to determine the Tm of the primers. Isothermal primer extension reactions were performed with Klenow fragment at the dark- adapted and irradiated photo stationary states. This revealed that only the para-azobenzene perturbed the extension by the enzyme. Further investigation with time course experiments to determine a yield using fluorescent fluorescein label and explore the possibility of photoswitchable DNA amplification using the para-azobenzene primers. OligonucIeotides bearing a novel photoswitchable moiety, phenylazopyridine, have been prepared. Directed Michaelis-Arbuzov reactions of support-bound internucleotide phosphite triesters with alkane-diamines were effected in the presence of iodine. The primary amine functionalised oligonucleotides were subsequently purified trityl on. This enabled resolution offast- and slow-isomers of oligomers.

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Gstach, Dieter. "Small sample performance of two approaches to technical efficiency estimation in noisy multiple output environments." Inst. für Volkswirtschaftstheorie und -politik, WU Vienna University of Economics and Business, 1998. http://epub.wu.ac.at/1190/1/document.pdf.

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This paper provides simulation evidence concerning some statistical properties of two different approaches to technical efficiency estimation for multiple-output production under noisy conditions: The Ray Frontier Approach (RFA) from Löthgren (1997) DEA+ proposed in Gstach (1996). RFA, unlike earlier approaches in the realm of stochastic frontier analysis, is capable of efficiency estimation in the case of multiple outputs as well and lends itself for comparison with DEA+. Several settings with varying sample sizes, noise to signal ratios and mean inefficiencies are investigated. (author's abstract)
Series: Department of Economics Working Paper Series

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48

Segal, Alina. "Development of membrane extraction with a sorbent interface for the analysis of environmental and clinical samples." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ65260.pdf.

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Weldegergis, Berhane Tekle. "Analysis of organochloro-pesticides in Eritrean water and sediment samples." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/49830.

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Thesis (MSc)--Stellenbosch University, 2004.
ENGLISH ABSTRACT: The choice of the sample preparation technique used in combination with a chromatographic technique in environmental analysis strongly influences the performance of the method as a whole. The main aim of this work was to evaluate methods like: micro liquid-liquid extraction (цLLE)and solid phase micro extraction (SPME) in combination with gas chromatography-electron capture detector (GCECD) and a recently developed technique named stir bar sorptive extraction (SBSE) combined with thermal desorption system-programmable temperature vaporizationgas chromatography-mass spectrometer (TDS-PTV-GC-MS) for the analysis of organochloro-pesticides (OCPs) in natural water and to make a comparison between them. The most suitable method was then selected for the analysis of water samples collected from Eritrea. An additional goal was to develop a sensitive method for the analysis ofOCPs in soil and sediment samples. цLLE-GC-ECD and SPME-GC-ECD methods were evaluated for the analysis of OCPs in water. The former allowed achieving a sensitivity of less than 100 ppt and the latter was able to detect down to the 1 ppt level. Both methods were found to be repeatable with %RSD of3% to 19% and 5% to 12% as well as linear with a range of 1:103 and 1:5x103 respectivey. SBSE-TDS-GC-MS was also investigated for the analysis of OCPs in water samples. With this technique a good sensitivity down to 1 ppt was also obtained. The less sensitive nature of the MS compared to ECD was hereby compensated for by the large amount of polydimethylsiloxane (PDMS) phase on the stir bar. The method was repeatable and linear with a range of 1:5000, which is similar to the one obtained for the SPME-GC-ECD method. All three methods were also tested with real contaminated water samples and a comparison of the three techniques in terms of sensitivity, linearity, repeatability, availability and cost effectiveness was done. As a method of choice in terms of the above criteria, SPMEGC- ECD was applied to the water samples collected from Eritrea. The presence of some oePs such as a-BBC (benzenehexachloride), heptachlor, heptachlor epoxide, endosulfan I, p,p'-DDE (dichlorodiphenylchloroethylene), endosulfan II, p,p'-DDD (dichlorodiphenyldichloroethane), endosu!fan sulfate and p,p'-DDT (dichlorodiphenyltrichloroethane) in some of the Eritrean water samples was demonstrated The SPME-GC-ECD technique for the analysis OCPs in soil and sediment samples was investigated. It was shown to be able to detect down to 1 pg/g (lppt) with good linearity and repeatability. The method was also evaluated for authentic soil samples. Due to a lack of time the method could not be applied for the analysis of the soil and sediment samples collected from Eritrea.
AFRIKAANSE OPSOMMING: Die keuse van 'n gepaste monster-voorbereidingsmetode wat gebruik word tesame met 'n chromatografiese skeidingtegniek in omgewings-analise het 'n beduidende effek op die algehele metode. Die doel van hierdie werk was om metodes soos mikrovloeistof- vloeistof ekstraksie (цLLE) en soliede fase mikro ekstraksie (SPME) in kombinasie met gaschromatografie met elektronvangs deteksie (GC-ECD) te ontwikkel vir die analise van organochloor-pestisiede (OCPs) in natuurlike water. Vervolgens is hierdie metodes vergelyk met die onlangs-ontwikkelde roerstaaf sorptiewe ekstraksie tegniek (SBSE) in kombinasie met termiese desorbsie-GCmassaspektrometriese deteksie (TDS-GC-MSD). Die mees geskikte metode is vervolgens gebruik vir die analise van Eritreaanse watermonsters. Daarbenewens was die doelook om 'n sensitiewe metode te ontwikkel vir die analise van OCPs in gronden sedimentmonsters. Beide цLLE en SPME-GC-ECD metodes is gekarakteriseer deur goeie herhaalbaarheid en lineariteit. Die sensitiwiteit van bogenoemde metodes was minder as 100 dele per triljoen (ppt) en 1 ppt, respektiewelik. Ook met SBSE-TDS-GC-MSD kon 'n deteksielimiet van 1 ppt bereik word. In hierdie geval is vir die verlies van sensitiwiteit van die MSD in vergelyking met die ECD, gekompenseer deur die groter hoeveelheid PDMS op die roerstaaf in vergelyking met 'n SPME apparaat. Die herhaalbaarheid en lineariteit van die metode is vergelykbaar met dié van die SPMEGC- ECD metode. Al drie metodes is vergelyk vir die analise van gekontamineerde watermonsters in terme van sensitiwiteit, liniêre bereik, herhaalbaarheid, toeganklikheid en kosteeffektiwiteit. SPME-GC-ECD is vervolgens gekies as metode van voorkeur vir die analise van Eritreaanse watermonsters. Die teenwoordigheid van sekere OCPs soos a-BHC, heptachloor, heptachloorepoksied, endosulfan I, p,p'-DDE, endosulfan II, p,p' -DDD, endosulfan sulfaat en p,p' -DDT in die monsters is gedemonstreer. Die toepasbaarheid van die SPME-GC-ECD metode vir die analise van OCPs in grond-en sedimentmonsters is ook geëvalueer, en dit was moontlik om so min as 1 pg/g waar te neem. Weens tydbeperkings was dit nie moontlik om Eritreaanse grondmonsters met die ontwikkelde metode te analiseer nie.

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Fitzgerald, Nicholas B. "The Small Volume Autonomous Water Sampler (SVAWS): An Innovative, Cost- Effective, Adaptable Protocol." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1533.

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As of 2007, U.S. pesticide use stood at 1.1 billion pounds with 80% of all usage in agriculture. Such realities pose a potentially dangerous threat to our surface water bodies. This research provides a detailed analysis of the design, operation and field testing of a prototype water sampler, the Small Volume Autonomous Water Sampler (SVAWS). The research includes a discussion of the design and construction of the SVAWS. Seven USGS employees operated the SVAWS in a number of different states and conditions in order to collect samples for pesticide analysis. Field-testing outcomes of the SVAWS were measured through a Participant Survey Request and a Likert-Scale Assessment. Overall, survey data proved the SVAWS to be an effective device for collecting water samples in different locations and conditions. Users also understood the SVAWS has significant potential for applications other than pesticide studies. While feedback did show a number of alterations or modifications could improve the design, the device proved to be effective across many of its goals, from valid water sampling to reducing costs of sample acquisition. Recommendations for future research include these and other avenues of research. A conclusion addresses the potential future of the SVAWS with respect to water sampling applications.

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Dissertations / Theses on the topic 'Environmental sample analysis'

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