Exposição à mistura de pesticidas em baixas doses: validação de método e aplicação a tecido adiposo de animais de experimentação (ratos Lewis)
Carregando...
Data
2009-07-28
Autores
Toledo Netto, Pedro [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A presença de pesticidas em matrizes ambientais e biológicas vem sendo investigada há décadas e estudos sobre a atuação de baixas concentrações destes contaminantes, como possíveis alteradores endócrinos e agentes carcinogênicos, ainda são incipientes. Portanto, o desenvolvimento de métodos analíticos para determinação destes compostos em matrizes biológicas torna-se necessário para se ter uma estimativa da quantidade que pode ser bioacumulada e relacioná-la ao desenvolvimento de alterações em diversos tecidos do organismo. O objetivo deste trabalho foi desenvolver e validar um método eficiente e rápido para determinação de resíduos dos pesticidas dicofol, dieldrin, endosulfan e permetrina em matriz de tecido adiposo de ratos. Estes pesticidas foram selecionados por apresentarem controvérsias quanto aos efeitos nocivos que podem causar ao homem, como por exemplo desregulação do sistema endócrino e, coincidentemente, por terem sido encontrados pela Agência Nacional de Vigilância Sanitária (ANVISA) em matrizes vegetais consumidas pela população brasilerira nos últimos anos. A principal dificuldade do trabalho foi estabelecer um procedimento experimental que permitisse a remoção de lipídios. Nesse sentido diversas condições experimentais foram avaliadas para eliminação destas macromoléculas, entre elas: extração em fase sólida, dispersão da matriz em fase sólida, envolvendo combinações de diversos adsorventes e extração por congelamento da amostra. Finalmente o método otimizado incluiu a extração das amostras de tecido adiposo com hexano em banho de ultrasom, seguida da extração em fase sólida (alumina) utilizando uma alíquota (1 mL) do extrato, sendo a eluição processada com hexano:diclorometano e, finalmente a concentração do eluato a secura, sua redissolução em isooctano e análise por GC/ECD. O método foi validado com sucesso...
The presence of pesticides in environmental and biological materials have been known for decades, but studies regarding their low concentration on potential carcinogenic and endocrine disruption effects are only beggining. Therefore, the development of quantitative analytical methods for pesticides in complex biological samples is important not only to estimate pesticide accumulation but also to evaluate possible tissue damages. The aim of this work was to develop and validade a simple, fast and senstive method for the pesticides dicofol, dieldrin, endosulfan and permethrin in rat adipose tissue. These specific molecules have been selected because they are the most frequently found in fruit and vegetables consumed in Brazil, according a survey performed by the National Health Surveillance Agency (Anvisa) and because they have been recently found to affect the endocrine system. The stablishment of an efficient procedure to eliminate lipids was a very difficult step. Therefore, several combinations of sorbents and eluents were tested copled to solid phase extraction, matrix solid phase dispersion and sample freezing extraction. Finally the optimized method includes the extraction from rat adipose tissue samples with hexane in ultrasonic bath. The resulting extract is submitted to solid phase extraction using alumina and eluted with hexane:dichloromethane. Extracted solvent was dried and redissolved in isooctane and analysed by GC/ECD. The method was sucessfully validated by following parameters: linearity range (analytical curve in sample extract): 5 to 1200 ng g-1; recovery at three different levels of sample fortification (50, 100 and 500 ng g-1 for dieldrin and endosulfan, 500, 1000 and 5000 ng g-1 for dicofol and permethrin); accuracy (recovery:75 – 119%); precision (coefficient of variation: 3 – 19%); selectivity... (Complete abstract click electronic access below)
The presence of pesticides in environmental and biological materials have been known for decades, but studies regarding their low concentration on potential carcinogenic and endocrine disruption effects are only beggining. Therefore, the development of quantitative analytical methods for pesticides in complex biological samples is important not only to estimate pesticide accumulation but also to evaluate possible tissue damages. The aim of this work was to develop and validade a simple, fast and senstive method for the pesticides dicofol, dieldrin, endosulfan and permethrin in rat adipose tissue. These specific molecules have been selected because they are the most frequently found in fruit and vegetables consumed in Brazil, according a survey performed by the National Health Surveillance Agency (Anvisa) and because they have been recently found to affect the endocrine system. The stablishment of an efficient procedure to eliminate lipids was a very difficult step. Therefore, several combinations of sorbents and eluents were tested copled to solid phase extraction, matrix solid phase dispersion and sample freezing extraction. Finally the optimized method includes the extraction from rat adipose tissue samples with hexane in ultrasonic bath. The resulting extract is submitted to solid phase extraction using alumina and eluted with hexane:dichloromethane. Extracted solvent was dried and redissolved in isooctane and analysed by GC/ECD. The method was sucessfully validated by following parameters: linearity range (analytical curve in sample extract): 5 to 1200 ng g-1; recovery at three different levels of sample fortification (50, 100 and 500 ng g-1 for dieldrin and endosulfan, 500, 1000 and 5000 ng g-1 for dicofol and permethrin); accuracy (recovery:75 – 119%); precision (coefficient of variation: 3 – 19%); selectivity... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Quimica analitica, Pesticidas, Cromatografia gasosa, Validação, Saúde humana, Analytical chemistry
Como citar
TOLEDO NETTO, Pedro. Exposição à mistura de pesticidas em baixas doses: validação de método e aplicação a tecido adiposo de animais de experimentação (ratos Lewis). 2009. 100 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Química, 2009.