Determinação simultânea de trialometanos e agrotóxicos em água empregando microextração em fase sólida e microextração em gota única por cromatografia gasosa

• Ano de defesa: 2011
• Autor(a) principal: Carlos, Elenice Aparecida
• Orientador(a): Queiroz, Maria Eliana Lopes Ribeiro de
• Banca de defesa: Rath, Susanne , Oliveira, Juraci Alves de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Agroquímica
• Departamento: Agroquímica analítica; Agroquímica inorgânica e Físico-química; Agroquímica orgânica
• País: BR
• Palavras-chave em Português: Trialometanos; Agrotóxicos; Cromatografia gasosa
• Palavras-chave em Inglês: Trihalomethanes; Pesticides; Gas chromatography
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ANALITICA
• Link de acesso: http://locus.ufv.br/handle/123456789/214

This study aimed to develop methods for simultaneous determination of organochlorine pesticides, trihalomethanes and pyrethroids in water. In order to provide environmentally friendly experimental protocols, gas chromatography with electron capture detector was associated with sample preparation techniques, that uses no organic solvent, or that this volume is significantly reduced, as in solid phase microextraction and single drop microextraction, respectively. The solid phase microextraction was carried out in the headspace (HS-SPME), and factors such as, addition of salt (Na2HPO4), temperature and extraction time for optimization were evaluated. Single drop microextraction was used in direct immersion mode (MEGU-DI), and experimental variables such as organic solvent, volume of the microdrop, contact time of the microdrop with the aqueous solution, stirring rate, addition of salt (NaCl) and sample volume were evaluated to maximize the performance of the technique. After optimization the methods were validated through the following parameters: linearity, intermediate precision, accuracy and limits of detection and quantification. Both methods allow the simultaneous analysis of organochlorine pesticides and pyrethroids in water, and the HS-SPME also allowed the analysis of trihalomethanes (THM). Coefficients of variation (CV) between 3 and 21% and relative recoveries between 70 and 125% were obtained. The protocols developed also showed selectivity and linearity adequate, with correlation coefficients (r) greater than 0.95. The detection limits of all pesticides under study are between 0.003 μg L-1 and 3 μg L-1, being all below their respective maximum contaminant level (MCL) allowed by national (Ministério da Saúde) and international (World Health Organization) legislation for drinking water. Drinking water samples were analyzed using the proposed methods and any of the pesticides were detected. Using HS-SPME, the trihalomethanes chloroform, bromodichloromethane and dibromochloromethane at concentrations of 4.4, 3.8 and 0.7 μg L-1, respectively, were detected in water samples. The sum of the concentration of trihalomethanes was less than 9 μg L-1 in all samples, a value lower than the MCL established by Brazilian legislation (Portaria 518 of the Ministério da Saúde, March 25, 2004), which is 100 μg L-1 for the sum of the four main trihalomethanes.