Electrochemical synthesis of Poly(melamine)-Poly (aspartic acid) copolymer for highly sensitive and selective determination of dopamine

In this study, a carbon paste electrode was modified using Poly (melamine)-Poly (aspartic acid) (PMEL-PASP/ CPE) copolymer film, and used for selective determination of dopamine (DA). Field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS), Mott-Schottky test, Raman, and electrochemical impedance spectroscopy (EIS) were used for characterization. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were used for electrochemical studies. The obtained results denoted high electrocatalytic activity for DA oxidation in phosphate buffer solution (PBS, pH = 7.4). A low detection limit of 0.78 nM with three dynamic ranges from 0.01 to 0.12 mu M, 0.32-54.0 mu M, and 60.0-1000 mu M and sensitivity of 2.712, 0.112, and 0.0501 mu A/mu M, respectively, were achieved. Acceptable reproducibility (RSD=4.81%), repeatability (RSD=0.39%), and long-term stability were obtained. Furthermore, the efficiency of the sensor in human blood serum was examined and yielded satisfactory results.