DECEA - Departamento de Ciências Exatas e Aplicadas

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/551

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2013 - 20142

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Autor: search.filters.author.Nascentes, Clésia Cristina

Resultados da Pesquisa

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    Electrochemical oxidation of ethinylestradiol on a commercial Ti/Ru0.3 Ti0.7O2 DSA electrode.
    (2013) Vieira, Karla Moreira; Nascentes, Clésia Cristina; Motheo, Artur de Jesus; Augusti, Rodinei
    The electrochemical oxidation of the hormone ethinylestradiol in an aqueous-methanolic medium by the application of a constant current of 40mAcm−2 in a flow cell with a commercial Ti/Ru0.3 Ti0.7O2 electrode was evaluated. The effect caused by the use of NaCl as a support electrolyte was also investigated. Hence, HPLC-UV analyses revealed that ethinylestradiol was almost totally consumed after a 60 min reaction time in the presence of NaCl. Conversely, much lower degradation rates were obtained when NaCl was not employed. Moreover, direct infusion ESI-MS and GC-MS analysis revealed that apparently no degradation products had been formed under these conditions. Hence, this study clearly demonstrated that such electrochemical treatment can be efficiently used to promote the complete degradation (and probably mineralization) of the hormone ethinylestradiol.
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    Photoelectrocatalytic oxidation of ethinylestradiol on a Ti/TiO2 electrode : degradation efficiency and search for by-products.
    (2014) Vieira, Karla Moreira; Paschoal, Fabiana Maria Monteiro; Zanoni, Maria Valnice Boldrin; Nascentes, Clésia Cristina; Augusti, Rodinei
    The degradation of ethinylestradiol (EE, an orally bio-active estrogen) in an aqueous-methanolic solution using a Ti/TiO2 thin-film electrode and UV radiation (a photoelectrocatalytic system) was evaluated. Hence, HPLC/UV analysis shows that EE (at 0.34 mmol) is totally consumed after 30 minutes of exposure to the photoelectrocatalytic system in the presence of Na2SO4 (0.1 mol•L−1) and with an applied bias potential of +1.0 V versus the Ag/AgCl reference electrode. Moreover, monitoring by direct infusion electrospray ionization mass spectrometry (ESI-MS) and SPME-GC/ MS (solid phase microextraction coupled with gas chromatography-mass spectrometry) reveals that apparently no degradation products are formed under these conditions. Hence, this study demonstrates that the photoelectrocatalytic system can be efficiently used to promote the complete degradation (and likely mineralization) of this hormone under these conditions.