SciELO - Scientific Electronic Library Online

 
vol.14 número2Determination of cadmium in sediments and in sewage sludge by slurry sampling electrothermal atomic absorption spectrometry using iridium as permanent modifierAnalysis of pesticide residues in Brazilian medicinal plants: matrix solid phase dispersion versus conventional (European Pharmacopoeia) methods índice de autoresíndice de materiabúsqueda de artículos
Home Pagelista alfabética de revistas  

Journal of the Brazilian Chemical Society

versión impresa ISSN 0103-5053

Resumen

LEITE, Oldair D.; FATIBELLO-FILHO, Orlando  y  BARBOSA, Aneli de M.. Determination of catecholamines in pharmaceutical formulations using a biosensor modified with a crude extract of fungi laccase (Pleurotus ostreatus). J. Braz. Chem. Soc. [online]. 2003, vol.14, n.2, pp. 297-303. ISSN 0103-5053.  http://dx.doi.org/10.1590/S0103-50532003000200018.

A carbon paste biosensor modified with a crude enzymatic extract of the Pleurotus ostreatus fungi as a laccase source is proposed for catecholamine determination in pharmaceutical formulations. This enzyme catalyzes the oxidation of adrenaline or dopamine in the corresponding quinones and the current obtained in the electrochemical reduction of each of the products is related to the concentration of these catecholamines in the sample solution. The effect of the laccase concentration from 0.29 to 1.8 U/mg of carbon paste, pH from 3.0 to 8.0, scan rate from 10 to 40 mV s-1 and potential pulse amplitude from 10 to 60 mV on the differential pulse voltammetric response was investigated. The relative standard deviation was smaller than 1.8% for a 2.8 x 10-4 mol L-1 hydroquinone solution at pH 7.0 (n=10). Recoveries varied from 97.3 to 101% for adrenaline and from 95.8 to 102% for dopamine. The analytical curves were rectilinear in the adrenaline concentration range from 6.0 x 10-5 to 7.0 x 10-4 mol L-1 and 7.0 x 10-5 to 4.0 x 10-4 mol L-1 for dopamine, with detection limits of 7.9 x 10-6 mol L-1 and 9.8 x 10-6 mol L-1, respectively. This biosensor was used for adrenaline and dopamine determinations in pharmaceutical formulations. The results obtained using the proposed biosensor are in close agreement with those obtained using an American Pharmacopoeia procedure at a 95% confidence level.

Palabras llave : laccase; Pleurotus ostreatus; catecholamines; biosensor.

        · resumen en Portugués     · texto en Inglés     · pdf en Inglés