Orientador: Profa. Dra. Ivanise Gaubeur / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Ciência e Tecnologia/Química, 2015. / O cromo e utilizado em varias atividades industriais e com o aumento da sua
presenca no ambiente se tem uma preocupacao em relacao a contaminacao
ambiental e considerando que as duas principais especies do elemento quimico
apresentam diferentes efeitos na saude humana e importante a realizacao da
especiacao quimica. Este trabalho propoe o desenvolvimento de metodo analitico
para especiacao de cromo combinada a microextracao liquido-liquido dispersiva
com gota organica flutuante (DLLME-FO) e deteccao por espectrometria de
absorcao atomica com chama de fonte continua com alta resolucao (HR-CS F AAS).
As variaveis que afetam a complexacao (valor de pH, tipo e concentracao dos
complexantes: dietilditiocarbamato de sodio (DDTC) e pirrolidinaditiocarbamato de
amonio (APDC), microextracao (volume dos solventes dispersor e extrator e
concentracao salina) e deteccao como a composicao da chama foram otimizadas de
forma univariada e multivariada. Apos as otimizacoes foram escolhidas como
melhores condicoes para complexacao, o complexante APDC (6,0x10-3 mol L-1) e
valor de pH 2,0 e 7,0, para Cr(VI) e cromo total, respectivamente. E as condicoes da
microextracao foram: 5%(m/v) de NaCl, 50 ¿ÊL de 1-undecanol (solvente extrator) e
300 ¿ÊL e 275 ¿ÊL de etanol (solvente dispersor). As caracteristicas analiticas obtidas
foram: faixa linear de 20-100 ¿Êg L-1 para Cr(VI) e cromo total. Para o Cr(VI) foram
obtidos limite de deteccao 0,35 ¿Êg L-1, coeficiente de variacao igual a 7% (n=10) e
fator de enriquecimento igual a 14. Para o cromo total foram obtidos limite de
deteccao 6,7 ¿Êg L-1, coeficiente de variacao igual a 18% (n=10) e fator de
enriquecimento igual a 10. A exatidao foi avaliada em material de referencia
certificado de agua e as concentracoes determinada e certificada foram
concordantes em um nivel de confianca de 95%. O metodo foi aplicado em amostras
de agua e as concentracoes de cromo encontradas estao dentro dos limites
estabelecidos pelas legislacoes vigentes. / Chromium is used in various industrial activities and increasing its presence in the
environment has been a concern in relation to environmental contamination and
considering that the two main species of the chemical element have different effects
on human health is important the realization of chemical speciation.This work
proposes the development of analytical method for chromium speciation combined
dispersive liquid-liquid microextraction based on floating organic drop (DLLME-FO)
and detection by high-resolution continuum source flame atomic absorption
spectrometric (HR-CS F AAS) . The variables that affect the complexation (pH, type
and concentration of complexant: sodium diethyldithiocarbamate (DDTC) and
ammonium pyrrolidinedithiocarbamate (APDC), microextraction (volume of disperser
and extractant solvents and salt concentration) and detection as the composition of
the flame were optimized using univariate and multivariate analysis. After the
optimizations were chosen as the best conditions for complexing the complexant
APDC (6.0x10-3 mol L-1) and pH value 2.0 to 7.0 for Cr (VI) and total chromium,
respectively. And the microextraction conditions were: 5% (w/v) NaCl, 50 ìL of 1-
undecanol (extractant solvent) and 300 ìL of ethanol and 275 ìL (disperser solvent).
The analytical characteristics were obtained: linear range of 20-100 ìg L-1 to Cr (VI)
and total chromium. For the Cr (VI) was obtained limit of detection 0.35 ìg L-1,
coefficient of variation 7% (n=10) and enrichment factor of 14. For the total chromium
was obtained limit of detection 6.7 ìg L-1, coefficient of variation 18% (n=10) and
enrichment factor of 10. The accuracy was evaluated in water certificate reference
material and determined and certified concentrations were agreed at the 95%
confidence level. The method was applied to water samples and chromium
concentrations found are within the limits established by current legislation.
| Identifer | oai:union.ndltd.org:IBICT/oai:BDTD:79213 |
| Date | January 2015 |
| Creators | Porto, Daniele Silva |
| Contributors | Gaubeur, Ivanise, Maltez, Heloisa França, Naozuka, Juliana |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf, 126 f. : il. |
| Source | reponame:Repositório Institucional da UFABC, instname:Universidade Federal do ABC, instacron:UFABC |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | http://biblioteca.ufabc.edu.br/index.php?codigo_sophia=79213&midiaext=71808, http://biblioteca.ufabc.edu.br/index.php?codigo_sophia=79213&midiaext=71809, Cover: http://biblioteca.ufabc.edu.brphp/capa.php?obra=79213 |
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