Investigation of the one-step electrochemical deposition of graphene oxide-doped poly(3,4-ethylenedioxythiophene)-polyphenol oxidase as a dopamine sensor.

In this paper, we fabricated poly(3,4-ethylenedioxythiophene) (PEDOT)-graphene oxide-polyphenol oxidase (PEDOT-GO-PPO) as a dopamine sensor. The morphology of PEDOT-GO-PPO was observed using scanning electron microscopy. Cyclic voltammetry was conducted to study the oxidation-reduction characteristics of dopamine. To optimize the pH, potential and limit of detection of dopamine, the amperometric technique was employed. The found limit of detection was 8 × 10 -9 M, and the linear range was from 5 × 10 -8 to 8.5 × 10 -5 M. The Michaelis-Menten constant ( K m ) was calculated to be 70.34 μM, and the activation energy of the prepared electrode was 32.75 kJ mol -1 . The electrode shows no significant change in the interference study. The modified electrode retains up to 80% of its original activity after 2 months. In the future, the biosensor can be used for the quantification of dopamine in human urine samples. The present modified electrode constitutes a tool for the electrochemical analysis of dopamine.