AN AMPEROMETRIC BIOSENSOR FOR TRANS- RESVERATROL DETERMINATION IN AQUEOUS SOLUTIONS BY MEANS OF CARBON PASTE ELECTRODES MODIFIED WITH PEROXIDASE BASIC ISOENZYMES FROM BRASSICA NAPUS

AM GRANERO, H FERNÁNDEZ, E AGOSTINI, MA ZÓN

ELECTROANALYSIS

Wiley-VCH

Lugar: Alemania; Año: 2008 vol. 8 p. 858 - 864

1040-0397

The catalytic properties of peroxidase basic isoenzymes (PBI´s) from Brassica napus towards trans resveratrol (t-Res) oxidation were demonstrated by the first time by conventional uv-visible spectroscopic measurements. The enzymatic reaction rate was studied under different experimental conditions and the kinetics parameters were determined. An amperometric biosensor based on Brassica napus PBI´s to determine t-Res is proposed by the first time. The method employs a dialysis membrane covered, PBI´s entrapped and ferrocene (Fc)-embedded carbon paste electrode (PBI´s-Fc-CP) and is based on the fact that the decreased amount of H2O2 produced by the action of PBI´s is proportional to the oxidised amount of t-Res in the solution. Comparative amperometric experiments showed that, in spite of PBI´s activity was much lower than commercial horseradish peroxidase (HRP) activity, t-Res was a much better substrate for PBI´s biosensors than those biosensors constructed by using HRP.             The PBI´s-Fc-CP biosensors showed a very good stability during at least twenty days. The reproducibility and the repeatability were 4.5% and 8.3%, respectively, showing a good biosensor performance. The calibration curve was linear in the t-Res concentration (ct-Res) range from 1 x 10-6 to 2.5 x 10-5 M, with a sensibility of (2.31 ±0.05) x 10 6 nAM-1. The lowest ct-Res value measured experimentally for a signal to noise ratio of 3:1 was 0.83 mM.