RESUMEN
A new biosensor was prepared based on conductive polymer poly ( 3 , 4-ethylenedioxythiophene ) ( PEDOT) and 1-pyrenebutanoic acid ( PBA) through π-π stacking, as well as hematin associated with PBA through coordinate bonds of Zr4+ and carboxyl group. Its stability and sensitivity were examined by cyclic voltammetry ( CV) , electrochemical impedance spectroscopy ( EIS) and current-time ( i-t) method. A pair of well defined and quasi-reversible redox peaks was observed when GCE/PEDOT/PBA/hematin was tested by CV in PBS without oxygen. The electron transfer rate constant was estimated to be 4. 8 s-1 . Results indicated that the PEDOT film enhanced the electron transfer process of hematin. When the i-t method was used to detect the response of biosensor to catechol with different concentrations, it displayed a linear response for the reduction of catechol in the range of 0. 5-200 μmol/L. The linear equation was i=0. 018C+0. 006 ( R=0. 9998), and the detection sensitivity was 0. 258 μA (μmol/L· cm2) with a detection limit of 0. 33 nmol/L (S/N=3). The results illustrate that the GCE/PEDOT/PBA/hematin biosensor is very sensitive and stable.