Avaliação da presença de dioxinas e PCBs no meio ambiente através de estudos de caso e viabilidade do uso de cromatografia gasosa acoplada a espectrometria de massas sequencial na análise destes compostos

Exportado OPUSMade available in DSpace on 2019-08-12T08:40:16Z (GMT). No. of bitstreams: 1 igor_cabreira_pussente.pdf: 5124328 bytes, checksum: 9ee3510634de9c16d24a2e23575b0c6d (MD5) Previous issue date: 9Os dibenzodioxinas-policlorados (PCDD), dibenzofuranos policlorados (PCDF) e dioxin-like PCB (dl-PCB) são hidrocarbonetos aromáticos polialogenados persistentes no meio ambiente devido ao baixo potencial de degradação térmica e microbiológica. O número de átomos de cloro e a posição em que estão ligados ao anel aromático determinam o potencial toxicológico destes compostos para os animais. A exposição humana e animal a estes congêneres é monitorada através de programas regulamentados pela União Européia para análise de dioxinas e PCBs em amostras ambientais e do gênero alimentício. Processos industriais e outras atividades humana, bem como incidentes indesejáveis, são as principais fontes de emissão desses compostos para o meio ambiente. O presente trabalho é dividido em três projetos, onde o Capítulo 1 apresenta os aspectos gerais sobre dioxinas e PCBs, detalhando informações sobre os compostos estudados, suas toxicidades e os dados técnicos de análises realizadas em todo o trabalho. No Capítulo 2 apresenta o estudo de caso da ave migratória Chasco-cinzento, no qual se analisou, por cromatografia gasosa acoplada espectrometria de massas de alta resolução (GC-HRMS) , os congêneres tóxicos de PCDD/Fs e dl-PCB, e os não-tóxicos ndl-PCBs em amostras ambientais (solo, ovos e embrião da ave, insetos e larvas de sua cadeia alimentar) coletadas durante o ciclo de reprodução na Holanda, para investigar possíveis rotas de contaminação da ave. Em ovos foram encontrados 13,08 pg TEQ-PCDD/Fs-dl-PCBs-WHO2005 g-1; em larvas ritnaald 7,08 pg TEQ-PCDD/Fs-dl-PCBs-WHO2005 g-1; e em solos ao redor dos ninhos 2,21 pg TEQ-PCDD/Fs-dl-PCBs-WHO2005 g-1. A comparação dos perfis de distribuição e as correlações de Pearson () calculadas entre as amostras, apresentam fortes indícios de que alguns insetos e larvas adquirem os congêneres de PCDD/Fs e PCBs quando em contato com o solo. Ao se alimentar dos insetos, a fêmea transfere para o ovo a contaminação adquirida. No Capítulo 3, foram apresentados os níveis de PCDD/Fs e PCBs em amostras de solos coletadas na área urbanda de Belo Horizonte/MG, analisadas por GC-HRMS. A faixa de concentração total em TEQ variou de 0,43 a 4,54 ng TEQ kg-1 d.m.. O maior nível médio em TEQ por área encontrado foi 2,68 (± 1,63) ng TEQ kg-1 d.m.. Os baixos níveis em TEQ alcançados sugerem que as regiões investigadas não são afetadas pelas possíveis fontes de emissão de dioxinas, embora Belo Horizonte/MG esteja circundada por algumas delas. No Capítulo 4 foi investigado o desempenho da técnica APGC-MS/MS como alternativa para análise de dioxinas, furanos e PCBs, em relação ao GC-HRMS e comparado com a legislação da União Europeia. O estudo apresenta os resultados de mais de 200 amostras reais, que foram obtidos e comparados com GC-HRMS, e a seletividade foi avaliada comparando-se os cromatogramas. A sensibilidade foi consideravelmente melhor no APGC-MS/MS do que a de GC-HRMS, enquanto o intervalo linear de ambas as técnicas cobriram semelhante faixa. As razões entre íons foram em sua maioria dentro da faixa de tolerância de ± 15%. concluiu-se que a determinação de dioxinas e de PCBS utilizando APGC-MS/MS cumprem os requisitos definidos pela Comissão Europeia. Contudo, devido desempenho geral um pouco melhor, o GC-HRMS é o método preferido para efeitos de controle por monitoramento.The polychlorinated dibenzo-p-dioxin (PCDD), polychlorinated dibenzofurans (PCDF) and 'dioxin-like' PCBs (dl-PCBs) are polyhalogenated aromatic hydrocarbons. Due to their low potential for thermal and microbiological degradation, these compounds are persistent in the environment. The number of chlorine atoms and the position where they are attached to the aromatic ring determine the toxicological potential of these compounds to animals. The human and animal exposure to these congeners has been monitored by official programs regulated by the European Union for the analysis of dioxins and PCBs in environmental and foodstuff samples. Industrial processes and other human activities, as well as undesirable incidents, are the main sources of emissions of these compounds to the environment. This work is divided in three main chapters. Hence, in Chapter 1 it is described the general aspects of dioxins and PCBs, with detailed information about these compounds, their toxicities and technical data regarding the analytical techniques performed herein. Chapter 2 presents the case study of migratory bird Northern Wheatear, in which gas chromatography coupled with high resolution mass spectrometry (GC-HRMS) is employed to analyze the toxic congeners of PCDD/Fs and dl-PCBs, as well the non-toxic NDL-PCBs. To investigate possible contamination in the bird routes, the following samples, collected during the bird reproductive cycle in the Netherlands, were analyzed: soil, eggs, embryos as well as insects and larvae of the bird food chain. The following levels were found in each sample: eggs (13.08 pg TEQ PCDD/Fs-dl-PCBs-WHO2005 g-1; 'ritnaald' larvae (7.08 pg TEQ PCDD/Fs-dl-PCBs WHO2005 g-1; soil (collected close to the bird nests: 2.21 pg TEQ PCDD/Fs-dl-PCBs-WHO2005 g-1. The comparison of the distribution profiles revealed strong evidence that some insects and larvae acquire congeners of PCDD/Fs and PCBs when in contact with soil. Then, the female transfers the contamination to the eggs upon feeding on insects. In Chapter 3, the levels of PCDD/Fs and PCBs, as analyzed by GC-HRMS, in soil samples collected in the urban area of Belo Horizonte/MG are presented. The total TEQ concentration ranged from 0.43 to 4.54 ng TEQ kg-1 dry matter (dm). The highest average level was 2.68 (± 1.63) ng TEQ kg-1 dm. The low levels achieved for all samples suggest that the investigated areas are not affected by possible sources of dioxin emissions, even knowing that Belo Horizonte is surrounded by a number of them. In Chapter 4 the performance of APGC-MS/MS as an alternative technique to GC-HRMS for the analysis of dioxins, furans and PCBs is investigated. The results of more than 200 real samples are analyzed. Hence, selectivity was assessed by comparing the chromatograms from both approaches, i. e. GC-HRMS and APGC-MS/MS. Sensitivity was considerably better for APGC-MS/MS than GC-HRMS whereas similar linear dynamic ranges were achieved for both techniques. Finally, the ratios between ions were mostly within the ± 15% tolerance range. Shortly, the determination of dioxins and PCBS by APGC-MS/MS meets the requirements defined by the European Commission. However, due to a slightly superior overall performance, the GC-HRMS technique is still the preferred method for dioxins analysis to be used for control purposes

Extraction solid-liquid and partition technique at low temperature (ESL-PBT) of Chlorpyriphos, Thiamethoxan e Deltametrin in apple for gas chromatographic

O objetivo deste trabalho foi otimizar e validar a técnica extração sólido-líquido e partição em baixa temperatura (ESL- PBT) para análise de resíduos dos agrotóxicos clorpirifós, thiamethoxam e deltametrina em amostras de maçã por cromatografia. Na etapa de otimização, as condições ideais para extração dos agrotóxicos de interesse de amostras de maçã fortificadas, foram determinadas empregando um planejamento fatorial. Foram avaliados: composição da mistura extratora, tipo de agitação e o tempo, força iônica da solução aquosa e clean up do extrato, para determinação das melhores condições de análise dos compostos de interesse. As amostras de maçã e a mistura extratora em fase única foram agitadas e deixadas em freezer por aproximadamente 8 horas. A matriz e a fase aquosa congeladas, com o abaixamento de temperatura, foram separadas da fase superior (solvente orgânico) ainda líquida. Esta fase foi submetida à etapa de clean-up e analisada por cromatografia gasosa, utilizando bifentrina como padrão interno. A técnica otimizada consiste em acrescentar a 3,0000 g de maçã, 1,0 mL de solução aquosa de NaH2PO4 a 0,2 mol L-1, 6,5 mL de acetonitrila, 1,5 mL de acetato de etila e submeter essa mistura a agitação mecânica por 30 minutos seguida de congelamento. Posteriormente, eluir o sobrenadante em uma coluna de 10,0 cm contendo 2,0000 g de florisil e 1,5000 g de sulfato de sódio anidro e analisar o extrato (10,0 mL) por cromatografia gasosa com detector por captura de elétrons. A etapa de clean-up foi necessária para minimizar a quantidade de interferentes provenientes da amostra, mas não prejudicou as porcentagens de recuperação dos analitos de interesse. O método otimizado foi validado determinando- se a seletividade, linearidade do detector, limites detecção e quantificação, precisão e exatidão. Os resultados mostraram que a ESL-PBT otimizada é seletiva, não apresentando picos interferentes. A técnica apresentou r2 médio de 0,992 quando se analisou a faixa de trabalho de 25,0 a 500,0 μg L-1. Os limites de detecção e quantificação do método estabelecido para o clorpirifós foi de 2,5 μg L-1 e 5,0 μg L-1, para o inseticida thiamethoxam foi de 5,0 μg L-1 e 15,0 μg L-1 e para a deltametrina foi de 10,0 μg L-1 e 20,0 μg L-1 respectivamente. A precisão foi dividida em repetitividade e precisão intermediária. A repetitividade apresentou coeficientes de variação entre 2,1% e 3,6% e a precisão intermediária obteve um coeficiente de variação máximo de 6,6%. A exatidão obteve coeficientes de variação entre 1,3 e 8,6% para o clorpirifós, 5,1 e 9,2% para o thiamethoxam e 5,1 e 16,2% para a deltametrina. A ESL-PBT se mostrou eficiente para análise de resíduos dos agrotóxicos de interesse em maçã com porcentagens de recuperação maiores que 70 % e limites de detecção abaixo dos limites máximos de resíduos (LMR) estabelecidos pela legislação brasileira para estes agrotóxicos neste tipo de alimento. A quantificação de agrotóxicos em matrizes complexas por cromatografia gasosa pode ser afetada pelos componentes da matriz. Neste trabalho, o efeito de matriz foi estudado, empregando curvas analíticas preparadas em solvente puro e em extratos de maçã (brancos) fortificados para quantificação dos agrotóxicos em extratos de maçã. Os resultados mostraram que os componentes da matriz podem afetar a quantificação dos agrotóxicos estudados. Entretanto, um estudo mais aprofundado deverá ser realizado para poder compreender melhor este fenômeno e sugerir formas adequadas para reduzir o efeito de matriz na quantificação de agrotóxicos em matrizes complexas por cromatografia gasosa. A técnica otimizada e validada foi aplicada em amostras de maçã adquiridas no comércio da cidade de Viçosa-MG. Nas amostras analisadas, foi constatada a presença de resíduos dos agrotóxicos clorpirifós na faixa de 0,25 a 0,30 μg L-1, concentrações inferiores às permitidas pela legislação brasileira.The objective of this work was to optimize and validate a solid-liquid extraction and partition technique at low temperature (ESL-PBT) for analysis of the pesticides chlorpyrifos, thiamethoxam and deltamethrin in apple samples by chromatography. During optimization, ideal conditions for extraction of the pesticides of interest from the apple samples were determined by employing a factorial experimental setup. Composition of the extracted mixture, agitation type and time, ionic force of the aqueous solution and clean-up of the extract were evaluated to determine the best conditions for analysis of the compounds of interest. The apple samples and an extractor mixture in a single phase were agitated and frozen for approximately 8 hours. The matrix and frozen aqueous phase were separated from the still liquid (organic solvent) upper phase when lowering the temperature. This phase was submitted to a clean-up step and analyzed by gas chromatography, using bifentrin as an internal standard. The optimized technique consisted of preparing a solution of 3.0000 g of apple, 1.0 mL of an aqueous NaH2PO4 (0.2 mol L- 1), 6.5 mL acetonitrile, 1.5 mL ethyl acetate and the mixture was submitted to mechanical agitation for 30 minutes and then frozen. After this step, the supernatant was separated in a 10.0 cm column containing 2.0000 g of florisil and 1.5000 g of anhydrous sodium sulfate and the extract (10.0 mL) was analyzed by gas chromatography with an electron capture detector. The clean-up stage was necessary to minimize the interferences in the sample, but did not jeopardize the recovery percentages of the analytes of interest. The optimized method was validated by determining selectivity, detector linearity, detection and quantification limits, precision and accuracy. The results show that optimized ESL- PBT is selective and shows no interference peaks. This technique presented na average r2 value of 0.992 when analyzing the working range of 25.0 to 500.0 μg L-1. The detection and quantification limits of the established method for chlorpyrifos were 2.5 μg L-1 and 5.0 μg L-1, for the thiamethoxam pesticide were 5.0 μg L-1 and 15.0 μg L-1 and for deltamethrin were 10.0 μg L-1 and 20.0 μg L-1, respectively. Precision was divided in repeatability and intermediate precision. Repeatability presented coefficients of variation between 2.1% and 3.6% and intermediate precision obtained a maximum coefficient of variance of 6.6%. Accuracy showed coefficients of variation between 1.3% and 8.6% for chlorpyrifos, 5.1% and 9.2% for thiamethoxam and 5.1 and 16.2 for deltamethrin. The ESL-PBT showed to be efficient for analysis of the pesticide residues of interest in apple with recovery percentages greater than 70% and detection limits lower than the maximum limits of the residues (LMR) established by Brazilian legislation for these pesticides in this type of food. Quantification of pesticides in complex matrixes by gas chromatography can be affected by matrix components. In this work, the effect of the matrix was studied, employing analytical curves prepared in pure solvent and in apple extracts (control) for quantification of pesticides in apple extracts. The results showed that the matrix components can affects the quantification of the pesticides studied. However, a deeper study should be performed to better understand this phenomenon and propose suitable methods to reduce the matrix effect on quantification of pesticides in complex matrices by gas chromatography. The optimized and validated technique was applied in apple samples acquired commercial in the city of Vicosa, MG, Brazil. In the analyzed samples, the presence of the pesticide residue chlorpyrifos was found in the range of 0.25 to 0.30 μg L-1, concentrations inferior to those permitted by Brazilian legislation

PCDD/Fs and PCBs in soils : A study of case in the city of Belo Horizonte-MG

Dioxins (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs)) are substances that represent a global concern due to their ubiquitous presence and toxicity. Industrial processes and other human activities as well as uncontrollable accidents are the main sources that release these pollutants into the environment. The presence of these compounds has been reported in soils from Europe, Asia and Africa, but currently, there is not much information of dioxin levels in soils from Brazil. This paper presents the levels of PCDD/Fs, dioxin-like PCBs (dl-PCBs) and non-dioxin-like PCBs (ndl-PCBs) in soils collected from urban areas of Belo Horizonte city, Minas Gerais State, Brazil. Total toxic equivalents (TEQ) observed ranged from 0.43 to 4.54 ng TEQ kg-1 d.m. The highest concentration TEQ found was 2.68 (± 1.63) ng TEQ kg-1 d.m. The low total TEQ achieved suggests that the locations evaluated are not being affected by possible sources of dioxin emissions, although Belo Horizonte is surrounded by a number of them

The performance of atmospheric pressure gas chromatography–tandem mass spectrometry compared to gas chromatography–high resolution mass spectrometry for the analysis of polychlorinated dioxins and PCBs in food and feed samples

Recently, gas chromatography tandem mass spectrometry (GC–MS/MS) has been added in EuropeanUnion (EU) legislation as an alternative to magnetic sector high resolution mass spectrometry (HRMS) for the analysis of dioxins and dioxin like polychlorinated biphenyls (dl-PCB) in food and feed. In this study the performance of APGC–MS/MS compared to GC–HRMS is investigated and compared with EU legislation. The study includes the legislative parameters, relative intermediate precision standard devia-tion (SRw,rel), trueness, sensitivity, linear range and ion ratio tolerance. In addition, over 200 real samplesof large variety and spanning several orders of magnitude in concentration were analyzed by both techniques and the selectivity was evaluated by comparing chromatograms. The SRw,rel and trueness were evaluated using (in-house) reference samples and fulfill to EU legislation, though the SRw,rel was better with GC–HRMS. The sensitivity was considerably better than of GC–HRMS while the linear range was similar. Ion ratios were mostly within the tolerable range of ±15%. A (temporary unresolved) systematic deviation in ion ratio was observed for several congeners, yet this did not lead to exceeding of the maxi-mum ion ratio limits. The APGC–MS/MS results for the non-dioxin-like-PCBs (ndl-PCBs) were negatively biased, particularly for PCB138 and 153 in contaminated samples. The selectivity of APGC–MS/MS was lower for several matrices. Particularly for contaminated samples, interfering peaks were observed in the APGC chromatograms of the native compounds (dioxins) and labeled internal standards (PCBs). These can lead to biased results and ultimately to false positive samples. It was concluded that the determination of dioxins and PCBs using APGC–MS/MS meets the requirements set by the European Commission. However, due to generally better selectivity and SRw,rel, GC–HRMS is the preferred method for monitoring purposes