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Otimiza??o de metodologias para determina??o de hidrocarbonetos polic?clicos arom?ticos:aplica??o em ?gua do Rio PotengiBarbosa, Andr?a Francisca Fernandes 05 December 2008 (has links)
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Previous issue date: 2008-12-05 / Petr?leo Brasileiro SA - PETROBRAS / This work aims to detect polycyclic aromatic hydrocarbons (PAHs) through optimized analytical techniques, such as gas chromatography with flame-ionisation detector (CGFID), gas chromatography coupled to mass spectrometry (CGMS), Fluorescence Spectroscopy of Molecular and Purpot of oils and greases (POG). Apply to chemometrics, Factorial Planning 23, in the preparation of samples by liquid-liquid extraction. The sample preparation was used for liquid-liquid extraction and factors in this sample was used for the application of factorial planning 23, such as the use of ultrasound, solvents
(dichloromethane, hexane and chloroform) and ratio of solvent / synthetic sample. These factors were assigned two types of levels: positive and negative. It was used to form the
cube to better analyze the answers. The responses of the eight combinations were obtained in reading the spectrofluorimetric. The optimization of equipment were used, and they served in the HPA's identification of the samples collected in Rio Potengi. The optimization of the equipment was observed every 16's and PAH in the samples was found that the HPA's came from contamination of the Rio Potengi. The contamination comes through organic household waste, hospital waste, and among other contamination that comes from industries that are installed around the River The factorial design of high validity, it was observed a more effective sample preparation. The factorial design of liquid-liquid extraction showed a way to spend less solvent in less time using an ideal solvent, but also a way to extract more analyte from the matrix itself is water. In planning a smaller form factor extraction was the use of ultrasound, the ratio 1:3 corresponding to a solvent and sample 3 and the best solvent was dichloromethane who presented a viable extraction, not discarding the possibility of using also the hexane. The chloroform and may be toxic not had a good extraction / Este trabalho tem como objetivo detectar hidrocarbonetos polic?clicos arom?ticos (HPAs) atrav?s de t?cnicas anal?ticas otimizadas, tais como: Cromatografia Gasosa com
Detector de Ioniza??o de Chama (CGDIC), Cromatografia Gasosa acoplada ? Espectrometria de Massa (CGEM), Espectroscopia de Fluoresc?ncia Molecular e Teor de ?leos e Graxas (TOG). Aplicar a Quimiometria, Planejamento Fatorial 23, na prepara??o de amostras por Extra??o L?quido-L?quido. A prepara??o da amostra utilizada foi ? extra??o l?quido-l?quido e nesta amostragem foi utilizado fatores para aplica??o do planejamento fatorial 23, tais como: a utiliza??o do ultrassom, solventes (diclorometano, hexano e clorof?rmio) e propor??o de solvente/amostra sint?tica. Esses fatores foram atribu?dos dois tipos de n?veis: positivo e negativo. E foi utilizada a forma de cubo para melhor analisar as respostas. As respostas das oito combina??es foram obtidas na leitura do espectrofluor?metro. A otimiza??o dos equipamentos foram utilizados, e eles serviram na identifica??o dos HPA s das amostras coletadas no Rio Potengi. Na otimiza??o do equipamento foi observado todos os 16 HPA s e nas amostras foi encontrados os HPA s que foram provenientes da contamina??o do Rio Potengi. A contamina??o por org?nicos vem atrav?s de lixos dom?sticos, lixos hospitalares, e
dentre outras contamina??es que vem de ind?strias que s?o instaladas em torno do Rio. O planejamento fatorial foi de grande validade, pois foi observada uma maneira mais eficaz de prepara??o de amostra. O planejamento fatorial da extra??o liquido-liquido mostrou uma maneira de gastar menos solventes em menos tempo utilizando um solvente ideal, como
tamb?m uma forma de extrair mais analito da pr?pria matriz ?gua. No planejamento fatorial a menor forma de extra??o foi a utiliza??o do ultrasom, a propor??o 1:3 que corresponde a um de solvente e 3 de amostra e o melhor solvente foi o diclorometano que apresentou uma vi?vel extra??o, n?o descartando a possibilidade de utiliza??o, tamb?m do hexano. O clorof?rmio al?m de ser t?xico n?o apresentou uma boa extra??o
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Avaliação da microbiota fúngica e presença de micotoxinas em amostras de plantas medicinais irradiadas, adquiridas no comércio varejista e atacadista / Evaluation of fungal bioburden and micotoxins presence in irradiated samples of medicinal plants purchased from wholesale and retail marketSimone Aquino 13 November 2007 (has links)
O presente estudo analisou os efeitos da radiação gama na sobrevivência de fungos em plantas medicinais embaladas, adquiridas do comércio atacadista e varejista, em diferentes períodos (0 e 30 dias) após o tratamento por irradiação. Cinco tipos de plantas medicinais [Peumus boldus, Cameilia sinensis, Maytenus ilicifolia, Pauilinia cupana and Cássia angustifolia), foram coletadas de diferentes municípios do Estado de São Paulo e submetidas ao tratamento por irradiação, utilizando-se uma fonte 60Co (tipo Gammacell 220), com doses de 5,0 kGy e 10 kGy e taxa de dose de 3,0 kGy/h. Amostras não irradiadas (grupo controle) foram usadas na contagem de fungos e diluições seriadas de 10-1 a 10-6 das amostras foram semeadas em duplicata e plaqueadas usando o método de cultura em superfície, em ágar Dicloran Glicerol 18% (DG18) e contadas após cinco dias a 25°C. O grupo controle revelou a presença dos gêneros Aspergilius e Penicillium, os quais são conhecidos como fungos toxigênicos e poucas amostras do grupo controle estavam dentro dos limites seguros, estabelecidos pela Organização Mundial de Saúde (OMS, 1998) para plantas medicinais. Em resposta a resistência do tratamento por ionização, na dose de 5 kGy, foi obsen/ado que os gêneros Aspergilius, Piioma e Syncephalastrum foram radiorresistentes, após o processo (dia 0 e 30° dia). O tratamento por radiação gama foi efetivo na descontaminação de todas as amostras de plantas medicinais, após 30 dias, com a dose de 10 kGy e mantidas em condições de vedação. Não foram detectadas aflatoxinas nas amostras do grupo controle, ainda que estas amostras estivessem intensamente contaminadas com Aspergilius flavus. / This present study evaluated the effect of gamma radiation on the fungal survival in packed medicinal plants, purchased from wholesale and retail market, in different period (0 and 30 days) after the treatment. Five kind of medicinal plants (Peurnus boldus, Camellia sinensis, Maytenus ilicifolia, Pauilinia cupana and Cassia angustifolia), were collected from different cities of São Paulo State, and submitted to irradiation treatment using a 60Co source (type Gammacell 220) with doses of 5,0 kGy and 10 kGy and at dose rate of 3.0 kGy/h. Non-irradiated samples (control group) were used for fungal counts and serial dilutions from 10-1 to 10-6 of the samples were seeded in duplicates and plated using the surface culture method in Dichloran 18% Glycerol Agar (DG 18) and were counted after five days at 25°C. The control group revealed the presence of genera Aspergillus and Penicillium, which are known as toxigenic fungi and a few samples of control group were within the safety limits of World Health Organization (WHO, 1998) to medicinal plants. In response to resistance of ionizing treatment, in the dose of 5 kGy, it was obsen/ed that the genera Aspergillus, Phoma and Syncephalastrum were radio-resistant after the process (day 0 and 30° day). The treatment by gamma radiation was effective in decontamination of all irradiated samples of medicinal plants, after 30 days, with the dose of 10 kGy and kept of veiled conditions. It was not detected aflatoxins in samples of control group, even though these samples were heavily contaminated with Aspergillus flavus.
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Utilização de técnicas compatíveis com o conceito de química verde na determinação de micropoluentes orgânicos em matrizes ambientais / The use of techniques compatible with the green chemistry concept for the determination of organic micropollutants in environmental matricesMaraissa Silva Franco 20 March 2015 (has links)
Contaminantes orgânicos há tempos são normalmente encontrados em baixíssimas concentrações no meio ambiente. Compostos orgânicos monoaromáticos, derivados dos subprodutos do petróleo, frequentemente são encontrados próximos a postos de combustíveis, onde há constantes vazamentos nos tanques de armazenamento. Poluentes emergentes, como exemplo os fármacos, também são temas constantes de pesquisas, devido à baixa taxa de degradação dos mesmos, mesmo após submetidos a sistemas de tratamento convencionais. Assim, a busca por técnicas de remediação, que visem a completa remoção de poluentes em baixas concentrações e metodologias analíticas que permitam o isolamento e detecção de tais compostos se torna essencial. Esse trabalho tem como uma de suas finalidades otimizar e aplicar um sistema de remoção de compostos orgânicos monoaromáticos presentes em solo, utilizando CO2 no estado supercrítico. A SPME-GC-MS foi otimizada e validada para a etapa de extração, com separação e quantificação por GC-MS dos contaminantes remanescentes após o solo ser submetido ao processo de remediação. Outro etapa do projeto, está relacionada com a determinação de sulfonamidas em lodo de esgoto. Para isso, um método rápido, fácil, barato e robusto de extração foi otimizado e validado, obtendo bons limites de quantificação (10-25 ng g-1) e detecção (4-9 ng g-1), com precisão e exatidão satisfatórios, de acordo com os valores estabelecidos pela ANVISA. Ainda com o propósito de determinar sulfonamidas em lodo de esgoto, um método LC online foi desenvolvido. A finalidade é promover o clean-up da matriz e extração dos analitos em um sistema de extração em fase sólida capilar online. Para isso, fez uso de duas colunas capilares (530 µm x 6,0 cm) dispostas em série, inseridas em um sistema cromatográfico capilar acoplado a detecção por espectrometria de massas. A primeira coluna teve como finalidade a retenção de interferentes presentes na amostra utilizando para isso, uma fase polimérica Strata-X. Já a segunda coluna, extraiu as sulfonamidas de interesse utilizando, para isso, uma fase polimérica aniônica Oasis Max. O extrato inserido no sistema de extração em fase sólida onlineera composto por 100 % solvente orgânico (acetonitrila); utilizando diferentes porcentagens de acetonitrila na etapa de carregamento, foi possível realizar clean-up adequado da amostra. A eluição dos analitos foi feita utilizando-se fase móvel acidificada. Com esse sistema, melhorou-se em até 30 % a extração de alguns compostos. Todos os métodos de preparo de amostra utilizados no trabalhos seguem a tendência atual sugerida pelo conceito do green chemistry. / The determination of organic contaminants in environmental matrices has long been a challenge for the scientific community, due to the very low concentrations they are present. Monoaromatic organiccompounds derived from petroleum sub-products are still a concern, because they are often found in environmental sites near gas stations, where there are constant leaks in storage tanks. Emerging pollutants,which include personal care products and pharmaceuticals, are also constant subject of research due to their low degradation rate, even after conventional treatment systems. Moreover, the research forremediation techniques aimed at complete removal of pollutants at low concentrations, as weel as new analytical methodologies for isolation and detection of such compounds are, both, essential. This workaims to optimize and apply a system to remove monoaromatic organic compounds present in soil, using CO2 in the supercritical state. As an analytical tool, SPME was optimized and validated with separation and quantification by GC-MS of selected contaminants remaining after the remediation process. Another research work developed is related to the determination of sulfonamides in sewage sludge.Firstly a methodology based on QuEChERS extraction method was optimized and validated, obtaining good results as limits of quantification, LOQ (10-25 ng g-1) and detection, LOD (4-9 ng g-1) withsatisfactory accuracy and precision, according to the values established by ANVISA. Still working to determine sulfonamides in sewage sludge, a new online sample preparation method was developed. Thepurpose of this method is to promote the matrix clean-up and concentration analytes in a capillary SPE system. It was used two capillary columns (500 µm x 6.0 cm) arranged in series in a capillarychromatographic system coupled to mass spectrometry. The first column was intended to retain interferences present in the sample, using a Strata-X polymer phase. The second column extracted sulfonamidesof interest, making use of an anionic polymer phase (Oasis MAX). The extract inserted in the online SPE system was composed of 100% organic solvent (acetonitrile); using different percentages of ACNwith appropriately pH at the loading stage, it was possible to achieve a satisfatory sample clean-up. The elution of the analytes was performed using an acidified mobile phase. This system improved by up to30% extraction yield of some compounds. All sample preparation methods used in the works follow the current trend suggested by the green chemistry concept.
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Simplifying Sample Preparation using Fabric Phase Sorptive Extraction: Analysis of Trace Targeted Pollutant Residues in Environmental, Biological and Food SamplesMesa, Rodolfo 26 October 2017 (has links)
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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A Novel Miniaturised Dynamic Hollow-Fibre Liquid-Phase Micro-Extraction Method for Xenobiotics in Human Plasma SamplesHansson, Helena January 2010 (has links)
Bioanalytical chemistry is a challenging field, often involving complex samples, such as blood, plasma, serum or urine. In many applications, sample cleanup is the most demanding and time-consuming step. In the work underlying this thesis a novel dynamic miniature extractor, known as a hollow-fibre liquid-phase microextractor (HF-LPME), was designed, evaluated and studied closely when used to clean plasma samples. Aqueous-organic-aqueous liquid extraction, in which the organic liquid is immobilised in a porous polypropylene membrane, was the principle upon which the extractor was based, and this is discussed in all the papers associated with this thesis. This type of extraction is known as supported-liquid membrane extraction (SLM). The aim of this work was the development of a dynamic system for SLM. It was essential that the system could handle small sample volumes and had the potential for hyphenations and on-line connections to, for instance, LC/electrospray-MS. The design of a miniaturised HF-LPME device is presented in Paper I. The extraction method was developed for some weakly acidic pesticides and these were also used for evaluation. In the work described in Paper II, the method was optimised on the basis of an experimental design using spiked human plasma samples. Paper III presents a detailed study of the mass-transfer over the liquid membrane. The diffusion through the membrane pores was illustrated by a computer-simulation. Not surprisingly, the more lipophilic, the greater the retention of the compounds, as a result of dispersive forces. The main focus of the work described in Paper IV was to make the HF/LPME system more versatile and user-friendly; therefore, the extractor was automated by hyphenation to a SIA system. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript.
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Methods to improve the sample quality of macromolecular complexes for structure determination by 3D Electron Cryo-Microscopy / Methoden zur Verbesserung der Probenqualität makromolekularer Komplexe zur Strukturbestimmung mittels 3D Kryo-ElektronenmikroskopiePlatzmann, Florian Peter 24 February 2012 (has links)
No description available.
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In vivo Solid Phase Microextraction for Brain Tissue AnalysisCudjoe, Erasmus January 2014 (has links)
New solid phase microextraction (SPME) method was developed for brain tissue bioanalysis on a liquid chromatography mass spectrometry platform.
To achieve set objectives, in vivo SPME desorption process was optimized for high throughput analysis through the development of a desorption device. Subsequently, new SPME coatings were developed for the extraction of polar neurotransmitters from biological matrices. In a targeted analysis, in vivo SPME was used to monitor of changes in the concentrations of endogenous compounds (multiple neurotransmitters) and exogenous drugs (carbamazepine and cimetidine) in the striatum of the rat brain extracellular fluid. For the first time, SPME was used for quantitative analysis of neurotransmitters and also study spacial distribution of other drugs in different regions of the brain extracellular fluid.
A new approach was developed for improved metabolites coverage in a global non-targeted metabolomics studies. The proposed in vivo method showed how complementary results can be obtained through the combination of microdialysis and SPME for simultaneous sampling of the brain extracellular fluid.
Finally, in a clinical application, SPME was used to monitor changes in the concentration of multiple neurotransmitters during deep brain stimulation of the pre-frontal cortex of the brain.
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Mass Spectrometric Applications for Diagnosing Metabolic and Endocrine DiseasesKushnir, Mark M. January 2008 (has links)
Disease-specific compounds (biomarkers) are analyzed in clinical laboratories to assist with diagnosing diseases. This thesis describes development and validation of liquid chromatography tandem mass spectrometry (LC-MS/MS) based tests for diagnosing a diverse group of endocrine and metabolic diseases. The analytical methods used on-line and off-line sample extraction and analytical derivatization as means of enhancing the analytical sensitivity, specificity and clinical utility. All developed methods were extensively validated and reference intervals for the biomarker concentrations were established in blood samples of healthy adults and children. Advantages of the LC-MS/MS as an analytical technique include possibility of simultaneous measurement of multiple analytes and ability of confirming their identity. In this thesis we proposed and evaluated approaches for the assessment of the specificity of analysis in the methods that use tandem mass spectrometry detection. To enhance throughput of the LC-MS/MS tests for the biomarkers that have endogenous or exogenous isomers an approach was developed for quantitation of isomers from unresolved chromatographic peaks. Using methods developed in this thesis we performed a study of the steroidogenesis in ovarian follicles of healthy women and women with polycystic ovary syndrome (PCOS). Obtained data on the steroid concentrations and associations between the steroid metabolites in the pathway would be helpful for better understanding of the ovarian pathophysiology. Potential biomarkers of PCOS were identified in the thesis; further studies will be necessary to confirm their clinical utility.
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Patterning nanocrystals using DNAWilliams, Shara Carol January 2003 (has links)
Thesis (Ph.D.); Submitted to the University of California at Berkeley, Berkeley, CA (US); 1 Sep 2003. / Published through the Information Bridge: DOE Scientific and Technical Information. "LBNL--55024" Williams, Shara Carol. National Institutes of Health (US) 09/01/2003. Report is also available in paper and microfiche from NTIS.
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Determinação de resíduos de compostos orgânicos em água por microextração líquido-líquido dispersiva (DLLME) E GC-(TQ)MS/MS / Simultaneous determination of organic compound residues in water samples by dispersive liquidliquid microextraction (DLLME) AND GC-(TQ)MS/MSMartins, Manoel Leonardo 29 November 2010 (has links)
The use of chemicals, which generates a lot off benefits, is responsible for the contamination of soil, water and foods. The concern about contamination of surface
and ground water systems by pesticides has grown in scientific circles, especially by the presence of pesticides and other compounds in water sources. Thus, rapid analytical methods, sensitive and efficient must be developed in order to verify the concentration levels of pesticides and other organic compounds in water samples
agree with those established by law to protect human health and the environment media. This study aimed to optimize, validate and implement an extraction method to
determine residues of mononitro, ketones, trifluralin, oxirane, lindane, 2,4-D ester, chlorpyrifos, bromoketal, α-endosulfan, β-endosulfan and endosulfan sulfate in
samples of tap water, industrial wastewater and groundwater by Dispersive Liquid-Liquid Microextraction (DLLME) modified and Gas Chromatography with Mass
Spectrometry Tandem using Triple Quadrupole type (GC-(TQ)MS/MS). The method is based on the rapid injection, with a syringe, of a mixture of an extractor solvent (50
μL of carbon tetrachloride) and an dispersor solvent (2.0 mL acetone) previously cooled (ice batch, 0 - 4 °C) in an aqueous sample (5.0 mL), contained in a 10 mL
graduated glass tube with conical bottom, with no pH correction and cooled (ice batch, 0 - 4 °C). It is not necessary to stir the sample in this step. Remove 25 μL of
the sedimented phase separated by simple sedimentation for 10 min. from the bottom of conical tube with a microsyringe and transferred to a vial of 200 μL for GC-
(TQ)MS/MS determination. The preconcentration factor obtained was 100 times. The method was validated by determining the limits of detection and quantification limits (LOD and LOQ), linearity, precision and accuracy. The calibration curves showed adequate linearity between 0.05 e 10 μg L-1 with coefficients of determination higher
than 0.993. The method showed good recovery values between 70 and 115%, RSD(%) ranged from 10.9 to 17.2%, LOQs between 0.02 and 0.09 μg L-1, and was considered adequate for the analysis of pesticide residues and other organic
compounds evaluated in water samples. After validation, the method was applied to samples of drinking water, industrial wastewater and groundwater. No pesticide
residues and other organic compounds evaluated were found in the water samples tested. / A utilização de substâncias químicas, que por um lado gera benefícios, por outro é responsável pela contaminação do solo, água e alimentos.A preocupação com a contaminação de sistemas aquáticos superficiais e subterrâneos por pesticidas tem crescido no meio científico, em especial pela presença de pesticidas e outras susbtâncias químicas em mananciais de água. Dessa forma, métodos analíticos rápidos, sensíveis e eficientes têm de ser desenvolvidos para verificar se
os níveis de concentração dos pesticidas e outras substâncias químicas em amostras de água estão de acordo com os estabelecidos pela legislação, a fim de resguardar a saúde humana e o meio ambiente. Este estudo teve como finalidade otimizar, validar e aplicar um método de extração e determinação de resíduos de mononitro, ketona, trifluralina, oxirano, lindano, 2,4-D-éster, clorpirifós, bromoketal, α-endosulfan, β-endosulfan e endosulfan sulfato em amostras água de torneira, efluente industrial e água subterrânea, aplicando a técnica DLLME modificada e quantificação por Cromatografia Gasosa acoplada à Espectrometria de Massas
Sequencial tipo Triplo Quadrupolo (GC-(TQ)MS/MS). A técnica de extração DLLME está baseada na injeção rápida, com auxílio de uma seringa, de uma mistura dos solventes extrator (50 μL de tetracloreto de carbono) e dispersor (2,0 mL de acetona) previamente resfriada em banho de gelo a uma temperatura entre 0 e 4 °C, em uma amostra aquosa (5,0 mL) contida em um tubo de vidro, com fundo cônico, graduados
com volume de 10 mL, sem correção de pH e mantida resfriada em banho de gelo entre 0 e 4 °C. O procedimento não requer agitação da amostra. Retira-se a fase sedimentada separada por sedimentação simples após 10 min., do fundo do tubo cônico com auxílio de uma microseringa de 25 μL e transfere-se para um frasco de
200 μL, para determinação no sistema GC-(TQ)MS/MS. O fator de pré-concentração obtido é de 100 vezes. Na validação do método determinaram-se os limites de
detecção e limites de quantificação (LOD e LOQ), linearidade, precisão e exatidão. As curvas analíticas apresentaram linearidade adequada entre 0,05 e 10 μg L-1 com
valores de coeficiente de determinação superior a 0,993. O método apresentou bons valores de recuperação, entre 70 e 115% e RSD(%) entre 10,9 e 17,2%, com LOQs entre 0,02 e 0,09 μg L-1. O método foi considerado adequado para a análise de resíduos dos pesticidas em estudo em amostras de água. Após a validação, o método foi aplicado em amostras de água de potável, efluente industrial e água subterrânea. Não foram encontrados resíduos dos pesticidas e outras substâncias químicas estudados nas amostras analisadas.
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