Electrochemical biosensor with pH regulation of CNTs/HRP multilayer for phenols.

An amperometric horseradish peroxidase (HRP) biosensor based on multilayer films containing carbon nanotubes (CNTs) and HRP was developed. With the pH regulation of the dispersion solution of CNTs, the sensitivity of the HRP multilayer film biosensor is tunable by the control of the dissociation of CNTs. The successful formation of multilayers was confirmed by UV-visible spectroscopy. The features of multilayers were characterized by SEM and electrochemical impedance spectrum (EIS). The performance of the HRP biosensor is reported for the amperometric detection of phenols. The biosensor presented a linear response for catechol from 9.1 × 10(-8) - 6.45 × 10(-5) mol/L, with a sensitivity of 0.00554 A · L/mol and a detection limit of 8.5 × 10(-8) mol/L. The study can provide a feasible simple approach for developing a new sensitivity tunable method for CNTs-based biosensors.