A glassy carbon electrode modified with a nanocomposite consisting of MoS₂ and reduced graphene oxide for electrochemical simultaneous determination of ascorbic acid, dopamine, and uric acid

We describe the synthesis of a hybrid nanocomposite consisting of MoS₂ and reduced graphene oxide (MoS₂/rGO) by a one-pot hydrothermal process, and the use of the material in an amperometric sensor. Scanning electron microscopy and nitrogen adsorption-desorption tests revealed that the nanocomposite possesses a porous and flower-like structure and a large specific surface. Cyclic voltammetry and differential pulse voltammetry demonstrated the nanocomposite to perform excellently in the electrochemical oxidation of ascorbic acid (AA), dopamine (DA), and uric acid (UA), respectively. The oxidation potentials are well separated (oxidation peaks at −64, 168 and 320 mV vs. Ag/AgCl) for AA, DA, and UA, and the respective detection sensitivities are strongly enhanced (0.12, 4.11 and 1.59 μA μM⁻¹ cm⁻²). The sensor was applied to the detection of the three species in spiked human serum samples where it gave recoveries ranging from 98.9 to 104.1 % (for n = 3). (author)