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Previous issue date: 2013-06-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Soil contamination by pesticides is an environmental problem that needs to be
monitored and avoided. However, the lack of fast, accurate and low cost analytical
methods for discovering residual pesticide in complex matrices, such as soil, is a
problem still unresolved. This problem needs to be solved before we are able to assess
the quality of environmental samples.
The intensive use of pesticides has increased since the 60s, because the
dependence of their use, causing biological imbalances and promoting resistance and
recurrence of high populations of pests and pathogens (upwelling). This has contributed
to the appearance of new pests that were previously under natural control.
To develop analytical methods that are able to quantify residues pesticide in
complex environment. It is still a challenge for many laboratories. The integration of
two analytical methods one ecotoxicological and another chemical demonstrates the
potential for environmental analysis of methamidophos.
The aim of this study was to evaluate an ecotoxicological method as "screening"
analytical methamidophos in the soil and perform analytical confirmation in the samples
of the concentration of the analyte by chemical method LC-MS/MS
In this work we tested two soils: a clayey and sandy, both in contact with the
kinetic methamidophos model followed pseudo-second order. The clay soil showed
higher absorption of methamidophos and followed the Freundlich model, while the
sandy, the Langmuir model.
The chemical method was validated LC-MS/MS satisfactory, showing all
parameters of linearity, range, precision, accuracy, and sensitivity adequate. In chronic
ecotoxicological tests with C. dubia, the NOEC was 4.93 and 3.24 for ng L-1 of
methamidophos to elutriate assays of sandy and clay soils, respectively. The method for ecotoxicological levels was more sensitive than LC-MS/MS
detection of methamidophos, loamy and sandy soils. However, decreasing the
concentration of the standard for analytical methamidophos and adjusting for the
validation conditions chemical acquires a limit of quantification (LOQ) in ng L-1,
consistent with the provisions of ecotoxicological test.
The methods described should be used as an analytical tool for methamidophos
in soil, and the ecotoxicological analysis can be used as a "screening" and LC-MS/MS
as confirmatory analysis of the analyte molecule, confirming the objectives of this
work / A contamina??o de solos por agrot?xicos ? um problema ambiental que precisa
ser monitorado e evitado. Por?m, a falta de m?todos de an?lise r?pidos, precisos e de
baixo custo, para res?duos de agrot?xicos em matrizes complexas, como o solo, ? um
problema ainda sem solu??o e precisa ser resolvido para que se possa avaliar a
qualidade de amostras ambientais.
O uso intensivo de agrot?xicos tem aumentado desde a d?cada de 60, causando a
depend?ncia do seu uso, provocando desequil?brios biol?gicos e favorecendo a
resist?ncia e a reincid?ncia de altas popula??es das pragas e pat?genos (ressurg?ncia), o
que contribui com o aparecimento de novas pragas que anteriormente estavam sob o
controle natural.
O desenvolvimento de m?todos anal?ticos que atendam as legisla??es ambientais
de quantificar res?duos de pesticidas em matrizes complexas ambientais continua sendo
um desafio para v?rios laborat?rios.
O objetivo deste trabalho foi avaliar um m?todo ecotoxicol?gico como
screening anal?tico do metamidof?s em solos e realizar a confirma??o anal?tica das
concentra??es do analito nas amostras pelo m?todo qu?mico LC-MS/MS.A integra??o
de dois m?todos anal?ticos, um ecotoxicol?gico e outro qu?mico, demonstra potencial
para a an?lise ambiental do metamidof?s.
Neste trabalho foram testados dois solos: um argiloso e outro arenoso, ambos
seguiram o modelo cin?tico de pseudo-segunda ordem para a adsor??o do metamidof?s.
O solo argiloso apresentou maior adsor??o de metamidof?s e seguiu o modelo de
Freundlich, enquanto o arenoso, o modelo de Langmuir.
O m?todo qu?mico LC-MS/MS validado foi satisfat?rio, apresentando todos os
par?metros de linearidade, intervalo, precis?o, exatid?o e sensibilidade adequados. Nos ensaios ecotoxicol?gicos cr?nicos com Ceriodapnhia dubia, as CENO foram 4,93 e
3,24 ng L-1 de metamidof?s para os elutriatos dos solos arenoso e argiloso,
respectivamente.
O m?todo ecotoxicol?gico apresentou-se mais sens?vel que o LC-MS/MS na
detec??o do metamidof?s, nos solos argiloso e arenoso. No entanto, diminuindo-se a
concentra??o do padr?o anal?tico do metamidof?s e ajustando-se as condi??es de
valida??o qu?mica, adquire-se um limite de quantifica??o (LOQ) em ng L-1, compat?vel
com o estabelecido no ensaio ecotoxicol?gico.
Os m?todos utilizados apresentam-se como uma boa ferramenta anal?tica para o
metamidof?s em solos, sendo que a an?lise ecotoxicol?gica poder? ser utilizada como
um screening e o LC-MS/MS como an?lise confirmat?ria da mol?cula do analito,
confirmando os objetivos desse trabalho
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/17777 |
| Date | 27 June 2013 |
| Creators | Chiquetti, Samanta Cristina |
| Contributors | CPF:13893734449, http://lattes.cnpq.br/2791074318745945, Bertoletti, Eduardo, CPF:67421237887, http://lattes.cnpq.br/6954478217916713, Medeiros, Guilherme Fulg?ncio de, CPF:03935531400, http://lattes.cnpq.br/1731390914884781, Leite, Ricardo Henrique de Lima, CPF:52264343400, http://lattes.cnpq.br/3801476460958779, Dantas, Tereza Neuma de Castro, CPF:07286937391, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4783139Z0&dataRevisao=null, Silva, Djalma Ribeiro da |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Qu?mica, UFRN, BR, F?sico-Qu?mica; Qu?mica |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Portuguese |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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