<i>Poly</i>(tannic acid)- Electrochemically Reduced Graphene Oxide Nanocomposite Based Voltammetric Sensor for the Simultaneous Determination of L-dopa and Tyramine

A highly efficient voltammetric sensor for L-dopa and tyramine (TYM) has been developed based on a nanocomposite of poly (tannic acid) ( p (TA)) and electrochemically reduced graphene oxide (rGO). The nanocomposite-modified electrode- p (TA)-rGO/GCE has been prepared using an electropolymerization procedure and is characterized by several analytical techniques. At the modified electrode, well-resolved peaks with enhanced peak current for L-dopa and TYM were obtained at lower overpotentials. Under optimized analytical conditions, the sensor has been used for the simultaneous determination of L-dopa in two dynamic ranges from 7.00 × 10 −6 M–2.00 × 10 −6 M and 1.00 × 10 −6 M–1.00 × 10 −7 M and TYM in the ranges from 8.00 × 10 −6 M–2.00 × 10 −6 M and 1.00 × 10 −6 M–6.00 × 10 −8 M. The proposed sensor offered high sensitivity with a limit of detection of 1.26 × 10 −8 M for L-dopa and 4.73 × 10 −9 M for TYM. The mechanistic aspects of the electro oxidation of the analytes were examined. The validity of the sensor has been assessed by the determination of L-dopa and TYM in artificial physiological samples and satisfactory results were obtained.