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Método de pré-concentração e extração de agroquímicos organoclorados em águas superficiais utilizando a técnica de microextração líquido-líquido

by Koltz Watthier, Elizabeth Aparecida

Abstract (Summary)
There are many agrochemicals residues in water sources in trace level. This way, the development and improvement of the analytical techniques to prepare the samples has been of great interest to reach low concentrations and to adapt thevolumes of the samples to the detection systems. For the development of this study the liquid-liquid microextraction technique was used, in the investigation of theorganochlorine agrochemical, Aldrin y-BCH (Lindane) and Heptachlor, using the Murray flask modified. The efficiency of the extraction depends on some experimental parameters such as the type of the extractor solvent, time of rest andshaking time of the sample. According to the experiments it established that the hexane was the best solvent, rest and shaking time of 10 minutes. Where studied the variation of the factors, pH, saline concentration and shaking time of the enriched sample water based on a factorial experimental 2³ as tool to find the best conditions of the analytes extraction. The optimized condition of the extraction, according to thefactorial experimental for the agrochemicals was: pH 7,0, saline concentration 5g NaCl and shaking time of the sample 10 minutes. The analytical curves were built through the calibration by the method, in the conditions of the pH 5,0, saline concentration 117g (2.0 mol.dm-3) and shaking time of 10 minutes. The recoveries of the agrochemicals Aldrin, y-BHC(lindane) and Heptachlor were between 0,4 and 4,8µg.dm-3, with values of correlation coefficient (r²), 0,9892, 0,9986 e 0,9962, respectively. The proposed methodology was applied in water samples from the Pato Branco River and its effluents, Rivers Divisa, Pinheiro, drinking water collection of Pato Branco River, Lambedor, Mangueirinha and Panela river in the state of Paraná, using the demonstrated conditions as the best by the factorial experiment. Through the liquid-liquid microextraction technique were dectected on Pinheiro River the presence of three agrochemicals studied with concentrations between 0,3 and 0,5 µg.dm-3. In this way, the efficiency of the analytical method for detection inconcentrations in trace level was proved
This document abstract is also available in Portuguese.
Bibliographical Information:

Advisor:Marcos Rivail da Silva; Clodoaldo Machado; Marcio Barreto Rodrigues

School:Universidade Regional de Blumenau

School Location:Brazil

Source Type:Master's Thesis

Keywords:waters agrochemicals liquid-liquid microextraction

ISBN:

Date of Publication:06/08/2006

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