Tesis
Desenvolvimento de eletrodos modificados com Poli-1-aminonaftaleno e Poli-1,5-diaminonaftaleno e aplicação na determinação de analitos de interesse farmacêutico
Fecha
2010-11-18Registro en:
SILVA, Quésia Guedes da. Development of electrodes modified with poly-1-aminonaphthalene and poly-1,5-diaminonaphthalene and application in the determination of analytes of pharmaceutical interest. 2010. 150 f. Tese (Doutorado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2010.
Autor
Silva, Quésia Guedes da
Institución
Resumen
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.