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-1sensitivity. 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.