Peroxidase-glucose oxidase-poly(amphiphilic pyrrole) bioelectrode for selectively mediated amperometric detection of glucose

Monoenzyme (HRP) and bilayer/monolayer bienzyme (HRP-GOX) bioelectrodes were realized bu the oxidative electropolymerization of amphiphilic pyrrole monomer 1 enzyme(s) mixtures, previously adsorbed on the surface of a glassy carbon electrode. Cyclic voltammetry measurements, carried out on poly 1-HRP modified electrodes showed that the electrocatalytical reduction of H2O2, in the presence of K4Fe(Cn)(6) as mediator, occurs at applied potentials well placed in the optimal potential range for amperometric detection. An optimization study concerning the mediator concentration the amount of the immobilized enzyme(s), the electrode material and the matrix structure (mono-or bilayer) was performed in order to obtain the glucose biosensor, At an applied potential of -0.1 V (vs. SCE), batch amperometric response to H2O2 for the HRP modified electrodes gave a sensitivity of fa. 280 mAM(-1) cm(-2) (up to 0.65 mM). For monolayer biosensor the sensitivity io glucose was ca. 170 mAM(-1) cm(-2) (up to 1.9 mM). The interference of ascorbate, urate and acetaminophen was found almost negligible.