Fabrication of Graphene–LaMnO3 Sensor for Simultaneous Electrochemical Determination of Dopamine and Uric Acid

Dopamine (DA) and uric acid (UA) are two of important bimolecular widely circulated in body blood. Therefore, development of simple and rapid methods for simultaneous determination of them in routine analysis has a great significance for many researchers. Therefore, for the first time, nanocomposite of graphene (Gr)LaMnO3has been utilized to fabricate the new electro-chemical sensor for simultaneously determining DA and UA via immobilizing Gr-LaMnO3 on the glassy carbon electrode(GCE). Because of the very god catalytic activities, greater electrical conductivity as well as higher surface area of the Gr-LaMnO3, DA and UA with two clearly described peaks have been simultaneously determined at the Gr-LaMnO3 modified electrode. Relative to peaks at the bare GCE, oxidation currents of DA and UA notably enhanced. Moreover, the catalytic peak current linearly depended on concentration of DA and UA in a range of 0.33 – 283.3 and 0.33 –283.3 μM with 0.040 and 0.051 μAμM-1 sensitivity. In addition, limit of detection (LOD) for DA and UA equaled 0.03 and 0.045 μM and diffusion coefficient for DA and UA diffusion at the modified electrode has been computed as 1.71×10−5 and 1.38×10−5 cm2s−1, respectively. It has been found that our electrode could have a successful application for detecting DA and UA in real samples. Thus, this condition demonstrated that the Gr-LaMnO3 nanocomposite displays good analytical performances to detect DA and UA.