"Preparação e aplicação de eletrodos de pasta de carbono modificados com ditiocarbamatos para análise de fármacos" / "Preparation and application of modified carbon paste electrodes with dithicarbamates for analysis of farmacos"

AUTOR(ES)

Rita de Cassia da Silva

DATA DE PUBLICAÇÃO

2006

RESUMO

The morpholinedithiocarbamate (Mor); piperidinedithiocarbamate (Pip) and pirrolidinedithiocarbamate (Pyr), three cyclic amines derived respectivelly from morpholine, piperidine and pirrolidine complex of Ruthenium (III) were synthesized and characterized by elemental analysis, infra-red spectroscopy, mass spectrometry and thermal analysis (thermogravimetry – TG – and differential thermal analysis – DTA). Elemental analysis showed that complexes of general formula Ru2DTC5.XH2O ((DTC = Mor, Pip e Pyr e X = 4, 1,5 e 2 respectively) were obtained. IR spectra revelead that the ligant behaves as a monodentate one with a duplet around 1000 cm-1. Mass spectrometry showed the molecular structures and the stability of the complexes, therefore they require high energy of collision to be broken up; some fragments could have been identified. Thermal analysis showed that after dehydration the complexes decomposed generating Ru2(SO4)3 and Ru2O3 as residues depending on the temperature, according to XDR analysis. After characterization the complexes were used as modifiers in the preparation of carbon paste electrodes. The performance of the modified electrodes (MCPE) was evaluated by cyclic voltammetry at different electrode composition and supporting electrolytes and potential intervals. On basis of peak definition and background current, the MCPERu2Pip5.1,5H2O, containing 10% of the complex, was chosen for further studies. The electrode was used in the determination of carbamazepine (CBZ) cyclic voltammetry. In the presence of CBZ the modifier current increased proportionally, to the analyte concentration in the 1,30 x 10-8 and 6,62 x 10-6 mol L-1. The method was applied in the determination of CBZ in synthetic urine sample spikes with the analyte with recoveries of 97 – 104%. Whem compared with a standart spectrophotometric procedure the results of the prposed method agreeded within 95% of confidence, according to the t-Student test.

ASSUNTO(S)

carbamazepine ditiocarbamato carbamazepina eletrodo de pasta de carbono modificado modified carbon paste electrode dithicarbamate

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