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Desenvolvimento de eletrodos modificados com Poli-1-aminonaftaleno e Poli-1,5-diaminonaftaleno e aplicação na determinação de analitos de interesse farmacêutico
(Universidade Federal de São Carlos, 2010-11-18) Silva, Quésia Guedes da; Faria, Ronaldo Censi; https://lattes.cnpq.br/8659496864305621; https://lattes.cnpq.br/7322456840289279
The aim of this work was to study the electrochemical response of the electrode modified with poly-1-aminonaphthalene (1-PAN) and poly-1 ,5- diaminonaphthalene (1,5-PDAN) for dopamine (DA), noradrenaline (NA) adrenaline (AD) and hydroquinone (HDQ) determination in pharmaceutical preparations by means cyclic voltammetry and differential pulse (DPV). The films of a 1-PAN and 1,5- PDAN were electropolymerized on the platinum electrode by cyclic voltammetry. The surface of the films of a 1-PAN and 1,5-PDAN was characterized by SEM technique. The best results were obtained for DA with electrodes prepared in solutions with 1- aminonaphthalene and 1,5-diaminonaphthalene 0.01 mol L-1 in the perchloric acid 1.0 mol L-1, and 70 cycles. The electrode of 1-PAN showed voltammetric response only after the cathodic pre-treatment of -0.7 V for 3 s, and for the electrode of 1.5- PDAN this pretreatment resulted in better definition of peak and higher density current. The first procedure developed was determination to the DA using the electrodes of a 1-PAN and 1,5-PDAN by technique DPV, the analytical curve was linear in the dopamine concentration ranges of 9.90 and 122 μmol L-1, with a detection limit of 4.22 μmol L-1 and 19.6 and 99.0 μmol L-1 with a detection limit of 4.25 μmol L-1, respectively. Further, we studied the determination of NA using electrodes of 1-PAN and 1,5-PDAN by technique DPV, presenting a linear response between 9.90 and 82.5 μmol L-1, with a detection limit of 0.85 μmol L-1 and 9.90 and 90.9 μmol L-1 with a detection limit of 1.81 μmol L-1, respectively. For determination of AD employing electrodes of 1-PAN and 1,5-PDAN by technique DPV, the calibration curve was linear over the concentration range between 29.1 and 145 μmol L-1, with a detection limit of 8.35 μmol L-1 and 38.4 and 166 μmol L-1 with a detection limit of 15.8 μmol L-1, respectively. Finally, a procedure for the determination of HDQ using the electrode of 1,5-PDAN by technique DPV was developed. The analytical curve was linear in the HDQ concentration range between 74.0 and 690 μmol L-1, with a detection limit of 24.1 μmol L-1.These results were concordants with the comparative method, the spectrophotometric, with an acceptable relative error, which suggests the applicability of electrochemical methods proposed in samples of pharmaceutical formulations.
Avaliação da contaminação e destino de multirresíduos de pesticidas organoclorados em água e sedimento utilizando cromatografia gasosa com detector de captura de elétrons (CG/ECD)
(Universidade Federal de São Carlos, 2010-11-18) Simão, Livia Pedrino; Rezende, Maria Olimpia de Oliveira; https://lattes.cnpq.br/6164624893473124; https://lattes.cnpq.br/1908502563885303
The use of pesticides for the purpose of improving agricultural productivity during the last century, played a key role in environmental contamination especially in surface water and sediment. Pesticides used on a large scale are the organochlorines, which, once present in the soil can be transported in large quantities by the rain, mainly reaching surface water. This study aimed to evaluate the contamination of water in the River Basin Monjolinho mutirressíduos by organochlorine pesticides, through physical, chemical, and also using gas chromatography with electron capture detector (GC / ECD) for detection of organochlorine compounds . Therefore, we sampled water and sediment at five points along the River Basin Monjolinho. The method presented achieved Imitating of detection (LOD) of 0.0039 to 0.86 mg L-1, limit of quantification (LOQ) of 0.07 to 2.59 mg L-1 and determination coefficient of 0.99. Through the results of chromatographic analysis, physico-chemical water and sediment, we found the presence of organochlorine compounds in all sampling points, a fact which may be related to persistent use of these compounds near the basin. These results support the view that the organochlorine pesticides are still part of the products used in agriculture of our country and also that the proposed methodology for the determination of organochlorine compounds multiressíduos is profitable and satisfactory.