Photocatalytic self-cleaning electrochemical sensor for honokiol based on a glassy carbon electrode modified with reduced graphene oxide and titanium dioxide

The authors describe the construction of a renewable electrochemical method for determination of honokiol in complex traditional Chinese herbs. A nanocomposite consisting of reduced graphene oxide and titanium dioxide was prepared and deposited on the surface of a glassy carbon electrode (GCE). This composite endows the GCE with self-cleaning capability via ultraviolet illumination. Under optimized conditions and at a typical working voltage of 0.54 V (vs. Ag/AgCl), the sensor has a linear response in the 0.025 to 10 μmol·L−1 honokinol concentration range, and the detection limit is 20 nmol·L−1 (at an S/N ratio of 3). The method was successfully applied to the determination of honokiol in cortex herbs and its galenicals.