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Desenvolvimento de procedimentos em fluxo para a determinação de Captopril, Dipirona e Paracetamol envolvendo multicomutação e inibição da quimiluminêscencia
(Universidade Federal de São Carlos, 2008-02-20) Oliveira, Geiser Gabriel de; Fatibello Filho, Orlando; https://lattes.cnpq.br/9859737944357808; https://lattes.cnpq.br/6504190570083114
In the present work, analytical procedures were developed using the multicomutação concept and inhibition of the chemilumenescence for the pharmaceuticals determination, such as, captopril, dipirona and paracetamol. For the control of the analysis module and acquisitions of data a microcomputer was used Pentiun 233 MHz equipped with an electronic interface (PCL - 711S), through programs in language Lab - View 7.0. The detection module consists of a cell of flow of polyethylene (in spiral) of 100 cm, a silicon fotodiodo (OSD-50E) and an electronic device (I model FAC 500), for the conditioning and amplification of the signs chemiluminescents. The analytical procedure was used for captopril determination in pharmaceutical formulations, the system bases on the inhibition of the sign chemiluminescence, between the luminol and the hypochlorite of sodium, when inserting the drug in the system. The analytical curve obtained was linear from 7,5 x 10-6 to 1,0 x 10-4 mol L-1 and detection limit was 9,0 x 10-7 mol L-1 with an analytical frequency of 180 h-1. The same system was used for dipirona determination, that system bases on the oxidation of the dipirona for the hexacianoferrate (III) of potassium, that is the catalyst of the reaction among the luminol-H2O2 happening like this the decrease of the sign quimiluminescente. The analytical curve presented a lineal strip of 1,0 x 10-4 to 9,0 x 10-4 mol L-1 with limit of detection of 9,0 x 10-5 mol L-1 obtaining an analytical frequency of 215 h-1. The studied analytical procedure, for the paracetamol determination in pharmaceutical formulations bases on the consumption of the reagent in excess of hypochlorite of sodium for the drugs, happening from that way to the decrease of the magnitude of the analytical sign. After the optimization of the system it was obtained a lineal strip of answer of 5,0 x 10-6 to 9,0 x 10 -5 mol L-1 with a limit of detection of 2,35 x 10-6 mol L-1 and a frequency of sampling of 180 determinations per hour. In the procedures quimiluminescentes involving multicommutation system stands out the bass consumption of reagents as well as a good analytical frequency.
Federalismo e reforma tributária no governo de Fernando Henrique Cardoso (1994-2002)
(Universidade Federal de São Carlos, 2008-02-20) Colombo, Luciléia Aparecida; Noronha, Eduardo Garuti; https://lattes.cnpq.br/6908348693613769; https://lattes.cnpq.br/9421549755358841
Nowadays, the flux method is one of the most widely used techniques promote growth of YBa2Cu3O7-ä single crystal superconductor. By using the material in a melted state, the reactions due to temperature are possible. To prepare single crystal superconductors of the family Y-Ba-Cu-O, a long period of time is necessary to melt the material in adequate conditions. In order to do this a satisfactory performance of the crucible is required; it must be resistant to any kind of chemical attack. In this work some materials used were investigated in crucibles. Platinum, gold (noble metals), oxides like Al2O3, ZrO2 showed problems when used in processing Y123 superconductors. To avoid this problem the zirconiaytria system is largely applied. Some authors have investigated the SnO2 crucible, but they found problems related to the densification of the SnO2. Recently, it was discovered that SnO2 can be densified without liquid phase, showing 99,7% of the theoretical density when sinterized up to 1300°C. Then, this condition was used to produce crucibles by slip casting to form the YBa2Cu3O7-ä single crystal superconductors without contamination. It was observed, in a first instance, that SnO2 crucibles are resistant to chemical attack of the flux that is rich in barium and copper. During the process it was observed an interface wall between the vial and the flux formed by BaSnO3. This protection is formed after heat treatment at 1025°C during 4, 17 and 24 hours. By increasing the treatment time (up to 24 hours), it was observed that the wall thickness increased too and it was possible stablish a relation between treatment time/thickness wall (that defines the resistance of chemical attack). This enabled the determination of the SnO2 crucible resistance to corrosion, under the flux condition. The second part of this work involved the Y123 single crystal growth. After produced, they were analysed by x-ray diffraction and SEM with microanalysis in cross sections of the crucibles to observe the BaSnO3 interface. It was observed that single crystals were not contaminated by tin, and they were analyzed through measuring magnetization vs. Temperature. The single crystal showed a critical temperature (Tc) around 90,5K with a transition width (Tc) around 19,5K before treatment with an oxygen flux at 450°C. After seven days of a second treatment under the same conditions, the Tc was increased to 92K with a decreasing to 4,5K in Tc. The results showed that SnO2 vials are resistant to BaO-CuO flux and appropriate to single crystal growth in YBa2Cu3O7-ä superconductors without external.