FERROCENE-CONTAINING POLYMERS AS ELECTRON-TRANSFER MEDIATORS IN CARBON-PASTE ELECTRODES MODIFIED WITH PQQ-DEPENDENT ALDOSE DEHYDROGENASE

The aim of this work was to improve an aldose-detecting biosensor base d on quinoprotein aldose dehydrogenase (ALDH). Polymer-bound ferrocene derivatives with four different structures were studied as electron t ransfer mediators between the coenzyme of ALDH, pyrroloquinoline quino ne (PQQ), and the conducting electrode material. The ferrocene polymer s were mixed into carbon paste, which was used for the preparation of aldose-detecting electrodes by immobilizing ALDH on the carbon paste s urface by adsorption. The current responses of the ferrocene polymer m odified electrodes were studied and the effect of the polymer structur e on the response was examined. The electrodes modified with all four polymers showed maximum response at the working potential around 300 m V (vs. Ag/AgCl). The operational stability of the ferrocene polymer mo dified electrodes was better than that of corresponding dimethylferroc ene modified electrodes. The ferrocene polymer modified electrodes see med to be suitable for the measurement of real samples.