Novel hybrid material based on Ru complex and its RuO2 oxide for dopamine and dopamine-uric acid simultaneous determination

Abstract

New binuclear ruthenium (III) complex was synthesized and characterized by elemental analysis, electrospray ionization mass spectrometry (ESI/MS), molar conductance, Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectrophotometry and cyclic voltammetry (CV). These techniques suggested that the Ru (III) complex presented a distorted octahedral coordination geometry. Then, hybrid materials (rGO/RuO2 and rGO/Ru complex/RuO2) were prepared after calcination of the Ru (III) complex with reduced graphene (rGO) under oxygen atmosphere at 700 and 400 °C, respectively. These composites were characterized by attenuated total reflection (ATR), scanning electron microscopy (SEM) and map analyses, X-ray diffraction (XRD), X-ray Photoelectron Spectroscopic (XPS), zeta potential analysis, cyclic voltammetry and electrochemical impedance spectroscopy (EIS). XRD analysis showed that the obtained oxides are crystalline solids, corresponding to RuO2 phases. In the second part of this study, the modified screen-printed carbon electrodes (SPCE) based on these hybrid materials were prepared and used as novel sensors for the detection of dopamine (DA) and uric acid (UA) using differential pulse voltammetry (DPV). The results showed that SPCE/rGO/Ru complex/RuO2 and SPCE/rGO/RuO2 electrodes exhibited a low dopamine detection limit (LOD) of 0.135 μmolL−1 and 1.22 μmol L−1, respectively. The simultaneous determination of DA and UA on SPCE/rGO/Ru complex/RuO2 showed LOD values of 57.4 and 93.48 nM. The reproducibility, repeatability and stability of this sensor were confirmed by RSD% values of 3.8, 2.2 and 4.5%, respectively.