Simultaneous determination of dopamine, uric acid and ascorbic acid with LaFeO3 nanoparticles modified electrode

LaFeO3 nanoparticles of approximately 22 nm in size were synthesized and characterized by XRD and TEM. A novel glassy carbon electrode modified with LaFeO3 nanoparticles was constructed and characterized by electrochemical impedance spectroscopy and cyclic voltammetry. The modified electrode exhibited strong promoting effect and high stability toward the electrochemical oxidation of dopamine (DA), which gave reversible redox peaks with a formal potential of 0.145 V (vs. Ag/AgCl) in pH 7.0 phosphate buffer solution. The anodic peak current (measured by constant potential amperometry) increased linearly with the concentration of dopamine in the range from 1.5 × 10−7 to 8.0 × 10−4 M. The detection limit was 3.0 × 10−8 M. The relative standard deviation of eight successive scans was 3.47% for 1.0 × 10−6 M DA. The interference by ascorbic acid was eliminated efficiently. The method was used to determine DA in dopamine hydrochloride injections and showed excellent sensitivity and recovery.