An electrochemical sensor based on MnO2 nanostructures modified reduced graphene oxide (rGO) for detection of dopamine
Lu Meng, Wenzhao Luo, Yuhui Zhou, Mishan Wu
Abstract
This study was performed to fabricate the electrochemical dopamine sensor based on MnO 2 nanostructures modified reduced graphene oxide (MnO 2 /rGO) electrode in the pharmaceutical sample. The GO nanosheets were synthesized using modified Hummers technique for modification of the glassy carbon electrode (GCE), and then reduced using the electrochemical technique. MnO 2 nanostructures were electrochemically deposited on rGO/GCE. The structural characterization using SEM and XRD showed the vertical growth of tetragonal crystalline of α-MnO 2 nanoplates on crumpled rGO nanosheets. The electrochemical studies using CV, and DPV indicated to higher electroactive surface area of MnO 2 /rGO/GCE and its higher sensitivity to the determination of dopamine than that on GCE, rGO/GCE and MnO 2 /GCE because of the synergetic effect of rGO nanosheets and high porous and sharp tips of MnO2 nanoplates. The amperometric studies showed that the sensitivity, detection limit and linear range of MnO 2 /rGO/GCE were obtained at 0.28808μA/μM, 0.002 μM and 0 to 1100 μM, respectively. The interference effect on the determination of dopamine showed the great selectivity of MnO 2 /rGO/GCE using the amperometry technique at 0.11V. The practical feasibility of MnO 2 /rGO/GCE as a dopamine sensor was evaluated in dopamine hydrochloride injection as a pharmaceutical product and results showed the good agreements between the electrochemical analysis and clinical laboratory data. Finally, the acceptable values of recovery (> 98.2%) and relative standard derivation (<3.91%) of the analytical analysis showed that the proposed dopamine sensor can be used as a precise and reliable sensor in complicated pharmaceutical samples.