Development of an amperometric electrode for determination of glutathione in erythrocytes / Desenvolvimento de um eletrodo amperometrico para determinação de glutationa em eritrocitos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

This work describes the development of a new amperometric method for glutathione determination in erythrocytes. For this task, a carbon paste electrode modified with tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) complex was developed. The modified electrode improved the transference of electrons between the glutathione and electrode being very sensitive for glutathione at an applied potential of 200 mV vs SCE. The modified electrode presented good characteristics in terms of selectivity, sensitivity and fast response, for glutathione detection. The best performance was verified using 20% (m/m) of TTF-TCNQ incorporated in the carbon paste and 0.5% of Nafion (m/v). The measurements were performed in phosphate buffer at pH 8.0 containing 0.1 mol L KCl and 0.5 mmol L EDTA. In these conditions, the modified electrode presented a linear response range from 5 to 340 µmol L for glutathione adjusted by the equation Dj = 0.7(±0.1) + 90.1(±0.4)[GSH] with a correlation coefficient of 0.9998 for n=20, where the current density is given in µA cm and the concentration of GSH in mmol L. The response time of the electrode was 0.5 s. Applying this electrode was possible to determine glutathione in erythrocytes after lyses without additional reagents. And comparing the results obtained with the electrode and a spectrophotometric method a good correlation was observed. The recovery tests showed that the amperometric method was better (98 - 102%) that the spectrophotometric one (90 - 92%).

ASSUNTO(S)

eletrodo de pasta de carbono glutathione tetrathiafulvalene-tetracyanoquinodimethane carbon paste electrode tetratiafulvaleno-tetracianoquinodimetano glutationa eritrocitos erythrocytes

ACESSO AO ARTIGO

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