One-pot synthesis of graphene–chitosan nanocomposite modified carbon paste electrode for selective determination of dopamine

Background: A simple, rapid, low-cost and environmentally friendly method was developed to determine dopamine (DA) in the presence of ascorbic (AA) and uric acid (UA) based on a novel technique to prepare a graphene–chitosan (GR–CS) nanocomposite and modify it on the surface of carbon paste electrode (CPE). For our design, CS acts as a media to disperse and stabilize GR, and then GR plays a key role to selective and sensitive determination of DA.
Results: Under physiological conditions, the linear range for dopamine was determined from 1 × 10^-4 to 2 × 10^-7 mol/L with a good correlation coefficient of 0.9961 in the presence of 1000-fold interference of AA and UA. The detection limit was estimated to be 9.82 × 10^-8 mol/L (S/N = 3). In order to study the stability and reproducibility, GR/CS/CPE underwent successive measurements in 10 times and then tested once a d for 30 d. The result exhibited 98.25% and 91.62% activities compared with the original peak current after 10-time measurements and 30-d storage.
Conclusion: The GR/CS/CPE has wide linear concentration range, low detection limit, and good reproducibility and stability, which suggests that our investigations provide a promising alternative for clinic DA determination.

Keywords
Dopamine; Selective determination; Surface modification of carbon paste electrode; Technique of one-pot synthesis