Facile Synthesis of Reduced Graphene Oxide/Mn₃O₄ Nanocomposite as a Platform for the Voltammetric Determination of Tramadol

We describe a simple hydrothermal method for preparing a nanocomposite of reduced graphene oxide/Mn 3 O 4 (rGO/Mn 3 O 4 ), and its use in electrochemically detecting tramadol (TRA). The sensor was constructed by using a glassy carbon electrode modified with a rGO/Mn 3 O 4 nanocomposite (rGO/Mn 3 O 4 /GCE) as an electro‐catalyst. The electrochemical properties of TRA at rGO/Mn 3 O 4 /GCE were studied using cyclic voltammetry (CV), chronoamperometry, and differential pulse voltammetry (DPV) in a phosphate buffer solution (PBS) with a pH of 8.0. The oxidation peak currents of TRA on rGO/Mn 3 O 4 /GCE increased compared to the bare GCE. This enhancement was attributed to the high surface area and excellent electron transfer performance of the rGO/Mn 3 O 4 nanocomposite on the surface of the electrode. Under optimal conditions, the oxidation peak currents exhibited a linear increase with the concentration of TRA within the range of 0.5 to 700.0 μM, and a detection limit (LOD) of 0.16 μM was achieved. This study has shown that the rGO/Mn 3 O 4 /GCE can effectively be used to analyze TRA in real specimens.