Recycling Systems Based on Screen-Printed Electrodes

Screen-printed enzyme electrodes sensitive to catecholamines were developed. The bioelectrocatalytic recycling systems investigated exploited the combination of laccase catalyzed catecholamine oxidation with the electrochemical reduction of the formed quinoic product or, alternatively, electrochemical oxidation of the catecholamine followed by quinoprotein glucose dehydrogenase (GDH) catalyzed reduction. Both systems allowed quantitation of nanomolar concentrations. The lower detection limit for dopamine was 50 nmol/L and 2 nmol/L for the laccase or GDH based system, respectively. The conditions for attaining the highest sensitivity were optimized. Relatively large oxygen fluctuations in solution can be tolerated without disturbing sensor performance. Good long-term stability can be provided for sensor operation and storage.