Electrochemical Study of Anionic Ferrocene Derivatives Intercalated in Layered Double Hydroxides: Application to Glucose Amperometric Biosensors

Layered double hydroxides (Zn(2)Cr(OH)(6)X center dot nH(2)O LDH) containing (3-sulfopropyl)ferrocene-carboxylate (FePSO(3)) and 1,1'-bis(3-sulfopropyl)ferrocene-carboxylate (Fe(PSO(3))(2)) as interlayer anions (X) have been prepared by the coprecipitation method and characterized by PXRD, FTIR, SEM and XPS. The electrochemical behavior of these hybrid materials has been evaluated by cyclic voltammetry. A new amperometric biosensor based on the immobilization of glucose oxidase in ZnCr-FePSO(3) hybrid material was presented, the intercalated anions playing the role of mediators that shuttle electrons between the FAD centers in the enzyme and the electrode surface. The performance of the resulting biosensor for glucose determination under anaerobic conditions was evaluated by chronoamperometry at 0.5 V. The sensitivity (65 mA M(-1) cm(-2)) determined in the concentration range 10-25 mu M is higher than sensitivities reported for other glucose biosensors based on LDH host matrices.