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 based on quinoprotein aldose dehydrogenase (ALDH). Polymer‐bound ferrocene derivatives with four different structures were studied as electron transfer mediators between the coenzyme of ALDH, pyrroloquinoline qninone (PQQ), and the conducting electrode material.
The ferrocene polymers were mixed into carbon paste, which was used for the preparation of aldose‐detecting electrodes by immobilizing ALDH on the carbon paste surface by adsorption. The current responses of the ferrocene polymer modified electrodes were studied and the effect of the polymer structure on the response was examined.
The electrodes modified with all four polymers showed maximum response at the working potential around 300 mV (vs. Ag/AgCl). The operational stability of the ferrocene polymer modified electrodes was better than that of corresponding dimethylferrocene modified electrodes.
The ferrocene polymer modified electrodes seemed to be suitable for the measurement of real samples.