Orientadores: Ivo Milton Raimundo Junior, María Cruz Moreno-Bondi / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-17T08:47:53Z (GMT). No. of bitstreams: 1 Pinheiro_SilviaCristinaLopes_D.pdf: 3031586 bytes, checksum: d04087a8b894575a32142d906b54d76b (MD5) Previous issue date: 2010 / Resumo: O objetivo deste trabalho foi desenvolver sensores fluorimétricos empregando os reagentes luminescentes ZOX (2-piridin-2-il-benzooxazol), [Ru(s2d)2(bim)] (complexo de Ru(II), onde s2d: 1,10-fenantrolina-4,7-di-il) bis(benzenossulfonato e bim: 2,2¿-biimidazol) bpySOH (4-[2-(4¿-metil-[2,2¿] bipiridil-4-il)-vinil]-fenol) e bpySOMA (2-metileno ácido butírico-4-[2-(4¿-metil-[2,2¿] bipiridil-4-il)-vinil]-fenil éster) para a determinação simultânea de metais pesados em águas. Os fluoróforos ZOX e [Ru(s2d)2(bim)] não forneceram resultados satisfatórios uma vez que sofreram lixiviação das matrizes (sol-gel) nas quais estavam imobilizados. Por outro lado, o reagente bpySOH e seu derivado bpySOMA forneceram bons resultados na caracterização em solução assim como na forma imobilizada. Estudos espectrofotométricos em solução com o bpySOH demonstraram estequiometrias de complexação ligante:metal de 1:1 para Cd(II), Ni(II) e Zn(II) e de 2:1 para Cu(II) e Hg(II). As constantes de estabilidade calculadas através de dados espectrofotométricos indicaram que os complexos de Cu(II), Hg(II) e Zn(II) são os mais estáveis. Estudos mostraram que Cu(II), Ni(II) e Zn(II) desativam a emissão do ligante, enquanto Hg(II) e Cd(II) incrementam essa propriedade. Experimentos de tempo de vida demonstraram um mecanismo de supressão estática da fluorescência para todos os complexos. Como estratégia de imobilização do ligante, avaliou-se uma matriz sol-gel (a partir do precursor TMOS). Imobilizado, o ligante mostrou resposta reversível para Cu(II), Hg(II) e Zn(II). O intervalo de resposta obtido para os íons metálicos foi de 2,50¿30,0 mmol L. A determinação simultânea em misturas contendo 2 ou 3 íons foi realizada utilizando Regressão por Mínimos Quadrados Parciais. Os modelos de calibração multivariada apresentaram resultados de previsão satisfatórios com valores de RMSEP inferiores a 3,00 mmol L. O derivado bpySOMA, por sua vez, apresentou comportamento semelhante em termos de valores de estequiometrias de complexação e constantes de estabilidade. Para imobilizá-lo, empregou-se um MIP seletivo para Cu(II). Estudos indicaram a seletividade para este metal frente a Cd(II), Hg(II), Ni(II), Pb(II) e Zn(II). Uma faixa de resposta foi obtida no intervalo de 0,1¿6,0 mmol L. O sensor foi aplicado à determinação de Cu(II) em águas de torneira fortificadas com o metal. Os resultados obtidos, quando comparados com um método de referência (FAAS) indicaram a aplicabilidade do sensor e que o mesmo apresenta potencialidade para trabalhos futuros. / Abstract: This thesis is aimed at developing fluorimetric sensors employing luminescent reagents ZOX (2-pyridin-2-yl-benzooxazole), [Ru(s2d)2(bim)](Ru complex, where s2d: 1,10-phenanthroline-4,7-diyl)bis(benzenesulfonate) and bim: 2,2¿-biimidazole), bpySOH (4-[2-(4¿-methyl-[2,2¿]bipyridinil-4-yl)-vinyl]-phenol) and bpySOMA (2-methylene-butyric acid 4-[2-4¿-methyl-[2,2¿]bipyridinyl-4-yl)-vinyl]-phenyl ester) for the simultaneous determination of heavy metals in waters. The fluorophores ZOX and [Ru(s2d)2(bim)] did not provide satisfactory results, being leached out from the matrix in which they were immobilized. On the other hand, bpySOH and its derivative bpySOMA provided good results in solution as well as after immobilization. Spectrophotometric studies of bpySOH in solution showed stoichiometries ligand:metal of 1:1 for Cd(II), Ni(II) and Zn(II) while 2:1 ratio was obtained for Cu(II) and Hg(II). Stability constants calculated from spectrophotometric data indicated that Cu(II), Ni(II) and Zn(II) complexes are the most stable. In addition, it was observed that Cu(II), Ni(II) and Zn(II) quench the fluorescence of the ligand, while Hg(II) and Cd(II) enhance this property. Lifetime studies demonstrated a static mechanism of quenching of fluorescence for all complexes. The ligand was immobilized in a sol-gel matrix (obtained from TMOS precursor), which presented reversible response for Cu(II), Hg(II) and Zn(II). The response range for the metal ions was 2.50¿30.0 mmol L. Simultaneous determinations of mixtures containing 2 or 3 ions were performed using the Partial Least Square method. Multivariate calibration models showed satisfactory prediction results, with RMSEP values lower than 3.00 mmol L. The derivative ligand bpySOMA showed similar results in terms of complexation stoichiometries and stability constant values. It was immobilized as a molecularly imprinted polymer selective to Cu(II), confirmed by the response of the non-imprinted polymer for Cd(II), Hg(II), Ni(II), Pb(II) and Zn(II) ions. A response range of 0.1¿6.0 mmol Lwas obtained. The sensor was applied to the determination of Cu(II) in tap water and the results agreed with those obtained by Flame Atomic Absorption Spectrometry. / Doutorado / Quimica Analitica / Doutor em Ciências

La détection et l'identification de bactéries pathogènes revêt une grande importance dans de nombreux domaines tels que la santé et l’industrie agroalimentaire. Dans ce contexte, les travaux de thèse s’intéressent à détection non invasive de Salmonella via la fraction volatile de son métabolome dont les métabolites volatils caractéristiques sont le sulfure d’hydrogène et la cadavérine. Ils illustrent également le concept de substrats osmogènes libérant des mCOV exogènes sous l’action d’enzyme spécifique d’Escherichia coli. Un premier capteur colorimétrique capable de distinguer le sulfure d’hydrogène du méthanethiol a été préparé. Il s’agit d’une matrice de silicate nanoporeuse dopée avec les réactifs N,N-diméthyl-p-phénylènediamine et ions Fe3+. Une bonne stabilité de l’intermédiaire réactionnel issu de ces réactifs, la quinonediimine (QD), est obtenue pour une forte concentration d’acide chlorhydrique. La réaction entre QD et 1000 ppm de sulfure d’hydrogène et de méthanethiol entraîne l’apparition respective d’une coloration verte et rouge-marron du capteur. Le capteur fluorimétrique de cadavérine, basé sur la formation d’un complexe fluorescent entre le Naphthol AS-BI déméthylé (ArOH) et la cadavérine, permet de détecter 250 ppb de cadavérine. La preuve de concept de substrats osmogènes a été illustrée avec la détection de p-nitrophénol (pNP) et de β-naphthylamine (β-NA) libérés en présence d’enzymes de E. coli, β-D-glucuronidase et L-alanine- β-naphthylamidase. Les capteurs nanoporeux produits, de taille de pores contrôlée, peuvent détecter 100 ppm de pNP, composé coloré (jaune) et 100 ppm de β-NA, composé fluorescent, ou encore 100 ppm de β-NA par dérivation chimique de ce dernier avec le diméthyl-p-aminocinnamaldéhyde (formation d’un produit rouge). En milieu biologique, l’eau est un interférent majeur. / Microbial contamination of food and biological samples is a big issue in the industry as much as in the medical field. In that context, the present thesis brings innovative solutions. A first explored way is the identification of Salmonella by detecting and measuring the specific metabolomics volatile organic compounds (mVOC) released, H2S and cadaverine. Another new concept is the use of osmogenic substrates able to release mVOC under the action of specific enzyme of Escherichia coli.A first colorimetric sensor able to discriminate H2S from CH3SH was produced, using a nanoporous silicate matrix doped with N,N-dimethyl-p-phenylenediamine and Fe3+ ions. A very acidic medium is needed to stabilize the “key” intermediate of the reaction, the quinonediimine species (QD), which gives with H2S and CH3SH a green and red-brown product, respectively. The fluorimetric sensor of cadaverine is based on the formation of a fluorescent complex between AS-BI demethylated Naphthol and cadaverine and can detect 250 ppb of cadaverine. A proof of concept of osmogenic substrates is given with the detection of p-nitrophenol (pNP) et de β-naphthylamine (β-NA) released under the action of Escherichia coli enzymes, β-D-glucuronidase et L-alanine- β-naphthylamidase. Various nanoporous sensors are produced with tailored pore size, which can detect 100 ppm of the yellow pNP, 100 ppm of the fluorescent β-NA and 100 ppm of the red product issued from the derivation of β-NA with dimethyl-p-aminocinnamaldehyde. In biological media, water remains the major interfering agent.