TCC Química

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https://repositorio.ifal.edu.br/handle/123456789/51

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Navegando TCC Química por Orientador "Lima, Phabyanno Rodrigues"

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    Desenvolvimento de sensor eletroquímico baseado em eletrodos impressos de carbono, modificados com Ácido Polixanturênico para detecção da Afloxitina B1
    (Instituto Federal de Educação Ciência e Tecnologia de Alagoas, 2019-12-05) Silva, Jéssica da Conceição da; Lima, Phabyanno Rodrigues; http://lattes.cnpq.br/9334426018309756; Cavalcante, Sarah Kelly Melo; http://lattes.cnpq.br/0820477133147241; Silva, Jailson dos Santos
    In the present work we describe the development of an electrode that uses xanturenic acid (AX) for the first time as an electrochemical probe, through a simple and efficient Aano-activated, nanomaterial modified carbon printed electrode immobilized with aptamers for the detection of aflotoxin. B1 (AFB1). The sensor surface was characterized by voltammetric techniques such as differential pulse voltammetry (VPD) and cyclic voltammetry (VC), which were used to study the behavior of modified electrodes, to optimize experimental parameters and obtain kinetic parameters. as a study of speed and pH. The electroactive species, quinone / hydroquinone, was electrogenerated in situ on the modified nanomaterials and AX electrode after cycles in the potential range between 0.5 and -1.0 vs. Ag at first sweep in 0.1 mol L-1 phosphate buffer (pH 5.5) with sweep rate of 50 mV s-1. After the activation process, the potential range around the redox quinone / hydroquinone pair was selected and the voltammograms were recorded at different speeds (5-20 mV s-1), then aptamer immobilization was performed, applied with the intention of to test the electrocatalytic activity for AFB1 oxidation. In addition, the electroactive species generated on the electrode surface showed inhibition against the immobilized aptamer when reacting with AFB1, causing a charge retention. Thus, from the results obtained the electrochemical aptensor developed showed a promising alternative to be applied in tests with real samples.
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    Determinação de ácido ascórbico: um sensor eletroquímico à base de pasta de carbono com 4-nitroanilina adsorvida em silica gel modificada
    (Instituto Federal de Educação Ciência e Tecnologia de Alagoas, 2019-12-05) Santos, Monik Tamíres Silva; Cavalcante, Sarah Kelly Melo; http://lattes.cnpq.br/0820477133147241; Lima, Phabyanno Rodrigues; http://lattes.cnpq.br/9334426018309756; Cavalcante, Sarah Kelly Melo; http://lattes.cnpq.br/0820477133147241; Silva, Jailson dos Santos
    The present work describes the development of a multiple wall carbon nanotube paste electrode (MWCNTPE) based on 4-nitroaniline (4NA) adsorbed onto silica gel modified with zirconium oxide (SZ) to detect ascorbic acid (AA). The sensing surface was characterized by Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Infrared Spectroscopy (FTIR). The electroactive species, hydroxylamine / nitrous (R-NHOH / R-NO), was electrogenerated in situ from 4Nitroaniline after cycling in the potential range between 0.5 and -1.0 vs. Ag / AgCl in the first scan in 0.1 mol L-1 PBS buffer (pH 7.0) with a scanning rate of 0.02 Vs-1. The modified electrode showed efficient electrocatalytic activity against the oxidation of ascorbic acid in 0.3 V vs. Ag / AgCl. Electrochemical measurements including Cyclic Voltammetry (VC) and Chronoamperometry were used to study the behavior of the surface of the modified electrode used. These techniques were used to optimize the experimental parameters. Thus, under optimized conditions, the sensor presented a linear response range of 0.5 - 3.0 μmol.L-1, LD (0.15 μmol.L-1), LQ (0.48 μmol.L-1) and sensitivity of 7.60 (mA.L.mmol-1) adding to the sensor positive factors in sensitivity and selectivity. This sensor was applied for the amperometric determination of AA in food samples. The results were consistent with those obtained with the standard titration procedure.