• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • Tagged with
  • 4
  • 4
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Simultaneous detection of drugs of abuse in waste water using gas chromatography-mass spectrometry

Mwenesongole, Ellen Musili January 2015 (has links)
Sewage epidemiology is increasingly becoming an alternative method of estimating drug usage and consumption patterns for a given population. With the constant emergence of new psychoactive substances such as cathinones and piperazines, versatile, reliable, specific and sensitive analytical methods are needed for their detection in complex matrices such as waste water. This thesis reports the development of an analytical method based on solid phase extraction, derivatization with pentafluoropropionic anhydride and analysis by gas chromatography-mass spectrometry for the simultaneous analysis of 29 illicit and therapeutic drugs of abuse. All 29 drugs could be reliably identified in spiked waste water samples using selected ion monitoring and splitless injection. Recoveries for the majority of the drugs were above 70 %. Linearity varied based on the analyte but was assessed in the range 2.0 x 10-4 to 1.4 μg/mL. Intra-assay and intermediate precision of the instrument was determined at 0.005, 0.1 and 1.0 μg/mL, with the majority of relative standard deviations less than 10 %. Limits of detection and quantification for drugs such as amphetamine and methamphetamine were better than reported values for liquid chromatography-tandem mass spectrometry, a more commonly used technique. Untreated 72 h composite waste water samples from Cambridge, UK, were analysed using a six-point standard addition curve. Eleven drugs of abuse were detected, including amphetamine, methamphetamine, butylone and 4-fluoromethamphetamine. The latter two having been detected for the very first time in waste water. Using the validated method, the consumption of heroin, ketamine, cocaine, methamphetamine and amphetamine, in Cambridge, UK, was estimated to be 399.4 ± 90.8, 2463.5 ± 182.5, 195.5 ± 95.4, 84.3 ± 59.1 and 38.9 ± 24.8 mg/day per 1000 inhabitants. This is the first reported validated method for the detection of both classic drugs of abuse and new psychoactive substances in waste water using gas chromatography-mass spectrometry and derivatization with pentafluoropropionic anhydride.
2

Stability Study of Wastewater During Storage at Three Different Temperatures Over a Three-Day Period

Kaskel, Parker 24 May 2022 (has links)
No description available.
3

Contaminants of Emerging Concern in U.S. Sewage Sludges and Forecasting of Associated Ecological and Human Health Risks Using Sewage Epidemiology Approaches

January 2013 (has links)
abstract: Many manmade chemicals used in consumer products are ultimately washed down the drain and are collected in municipal sewers. Efficient chemical monitoring at wastewater treatment (WWT) plants thus may provide up-to-date information on chemical usage rates for epidemiological assessments. The objective of the present study was to extrapolate this concept, termed 'sewage epidemiology', to include municipal sewage sludge (MSS) in identifying and prioritizing contaminants of emerging concern (CECs). To test this the following specific aims were defined: i) to screen and identify CECs in nationally representative samples of MSS and to provide nationwide inventories of CECs in U.S. MSS; ii) to investigate the fate and persistence in MSS-amended soils, of sludge-borne hydrophobic CECs; and iii) to develop an analytical tool relying on contaminant levels in MSS as an indicator for identifying and prioritizing hydrophobic CECs. Chemicals that are primarily discharged to the sewage systems (alkylphenol surfactants) and widespread persistent organohalogen pollutants (perfluorochemicals and brominated flame retardants) were analyzed in nationally representative MSS samples. A meta-analysis showed that CECs contribute about 0.04-0.15% to the total dry mass of MSS, a mass equivalent of 2,700-7,900 metric tonnes of chemicals annually. An analysis of archived mesocoms from a sludge weathering study showed that 64 CECs persisted in MSS/soil mixtures over the course of the experiment, with half-lives ranging between 224 and >990 days; these results suggest an inherent persistence of CECs that accumulate in MSS. A comparison of the spectrum of chemicals (n=52) analyzed in nationally representative biological specimens from humans and MSS revealed 70% overlap. This observed co-occurrence of contaminants in both matrices suggests that MSS may serve as an indicator for ongoing human exposures and body burdens of pollutants in humans. In conclusion, I posit that this novel approach in sewage epidemiology may serve to pre-screen and prioritize the several thousands of known or suspected CECs to identify those that are most prone to pose a risk to human health and the environment. / Dissertation/Thesis / Ph.D. Civil and Environmental Engineering 2013
4

Determinação de cocaína e metabólitos em amostras de urina de usuários da droga e em amostras ambientais / Determination of cocaine and metabolites in users urine samples and in environmental sample

Campestrini, Iolana, 1985- 27 August 2018 (has links)
Orientador: Wilson de Figueiredo Jardim / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-27T18:04:13Z (GMT). No. of bitstreams: 1 Campestrini_Iolana_D.pdf: 2742870 bytes, checksum: 20a25893a0acbb614cce027eda2bef08 (MD5) Previous issue date: 2015 / Resumo: Este trabalho apresenta a determinação de sete subprodutos da cocaína (COC), incluindo a benzoilecgonina (BE), em amostras de urina de usuários da droga. Com os dados obtidos foi avaliada a incerteza no cálculo da razão entre a BE e o somatório dos demais metabólitos da COC, sendo que a razão média encontrada foi utilizada para inferir sobre o consumo de COC aplicando a epidemiologia do esgoto. Os resultados dessa razão apresentaram grande amplitude de valores e mostrou elevada influência sobre estimativa do consumo. Apresenta, também, a avaliação da eficiência de remoção (ER) para a COC e BE nas estações de tratamento de esgoto (ETE) Anhumas e Capivari e da qualidade de mananciais e de águas de abastecimento do estado de São Paulo. Os melhores índices de remoção foram observados para a ETE Capivari, os quais variaram entre 96 e 99%. Tanto nas amostras de mananciais como nas amostras de água de abastecimento, a BE foi determinada em maiores concentrações do que a COC. Nos rios Piracicaba, Capivari e Anhumas observaram-se os maiores níveis de BE, os quais variaram entre 300 e 1000 ng L-1. Nas amostras de água de abastecimento do rio Capivari e do rio Atibaia foram determinadas as maiores concentrações de BE, chegando a 650 ng L-1. Para a análise dessas amostras foi utilizada a extração em fase sólida (SPE) seguida da cromatografia líquida acoplada à espectrometria de massas sequencial (LC-MS/MS). No geral, o método apresentou exatidão superior a 70%, com coeficiente de variação menor do que 15% no nível de ng L-1 / Abstract: This work describes the determination of seven cocaine (COC) metabolites, including the major one benzoylecgonine (BE), in urine of cocaine users. These determinations allowed the calculation of the ratio between BE concentration and the sum of the other COC metabolites concentration, as well as allowed an assessment of the uncertainty involved in this ratio. The ratios were used to estimate cocaine consumption applying sewage epidemiology yielding high amplitude of values among the ratios calculated. The work also presents COC and BE removal efficiency (RE) in two wastewater treatment plant (WWTP), namely Anhumas and Capiravi, where the best RE were obtained for the Capivari WWTP, which varied between 96% and 99%. Also the assessment of water quality, for both surface and drinking waters of the State of São Paulo, Brazil, was evaluated. The metabolite BE occurred more frequently and at higher concentrations when compared to COC, considering the same samples. For surface water, the highest BE concentrations were found in the Piracicaba, Capivari and Anhumas rivers, and the results varied from 300 to 1000 ng L -1. For drinking waters, the highest BE concentration was found in waters from Capivari and Atibaia rivers, at 650 ng L-1. Solid phase extraction and the liquid chromatography tandem mass spectrometry (LC-MS/MS) were used for the determination of the compounds. In general, the method presented accuracy above 70% and relative standard deviation below 15%, at ng L -1 level / Doutorado / Quimica Analitica / Doutora em Ciências

Page generated in 0.0825 seconds