Effect of carbon black functionalization on the analytical performance of a tyrosinase biosensor based on glassy carbon electrode modified with dihexadecylphosphate film.

Carbon Black (CB) has acquired a prominent position as a carbon nanomaterial for the development of electrochemical sensors and biosensors due to its low price and extraordinary electrochemical and physical properties. These properties are highly dependent on the surface chemistry and thus, the effect of functionalization has been widely studied for different applications. Meanwhile, the influence of CB functionalization over its properties for electroanalytical applications is still being poorly explored. In this study, we describe the use of chemically functionalized CB Vulcan XC 72R for the development of sensitive electrochemical biosensors. The chemical pre-treatment increased the material wettability by raising the concentration of surface oxygenated functional groups verified from elemental analysis and FTIR measurements. In addition, it was observed an enhancement of almost 100-fold on the electron transfer rate constant (k0 ) related to unfunctionalized CB, confirming a remarkable improvement of the electrocatalytic properties. Finally, we constructed a Tyrosinase (Tyr) biosensor based on functionalized CB and dihexadecylphosphate (DHP) for the determination of catechol in water samples. The resulting device displayed an excellent stability with a limit of detection of 8.7 × 10-8  mol L-1 and a sensitivity of 539 mA mol-1  L. Our results demonstrate that functionalized CB provides an excellent platform for biosensors development.