One-pot Electro-polymerized SDPAS/PPy/CNTs Modified Electrode for Selective Detection of Dopamine

To improve the performance of dopamine (DA) detection in the presence of ascorbic acid (AA) and uric acid (UA), sodium diphenylamine sulfonate/polypyrrole/multi-walled carbon nanotubes (SDPAS/PPy/CNTs) film was fabricated on the surface of gold electrode through one-pot polymerization initiated by electrochemical oxidation. SDPAS were covalently embedded into the backbone of PPy to endow the resultant film with numerous negative-charged terminals, resulting in selective pre-adsorption of protonated DA⁺ on the electrode and switching the following anodic reaction to be an adsorption-controlled process. The detection of DA in the presence of AA and UA by square wave voltammetry method showed an outstanding repeatability with the relative standard deviation of 0.45 %. A good linear relationship was observed between the oxidative peak current and the concentration of DA in the range of 0.827–104 μM (R²=0.993), and the limit of detection (LOD) was calculated to be 0.105 μM (S/N=3).