Preparation of a Cu/CuO-vertical graphene microelectrode for the simultaneous determination of epinephrine and 2-aminoadenosine

Abstract

The correlation between neurotransmitters, drugs, and neurotoxicity is important for disease diagnosis. Herein, a flexible Cu/CuO-vertical graphene (VG) microelectrode-based electrochemical sensor was developed for the detection of epinephrine (Ep) and 2-aminoadenosine (AAD). A Cu/CuO-VG microelectrode with a diameter of 200 μm was prepared by optimizing the Cu/CuO nanoparticle distribution and VG film thickness using one-step chemical vapor deposition. Under the synergistic electrocatalytic effect of Cu/CuO nanoparticles and graphene nanosheets, as well as the coordination of the VG film for bulk ion adsorption and long-range electron transport, the optimized Cu/CuO-VG microelectrode responded sensitively to Ep and AAD. Quantitative detection of Ep and AAD was achieved over a wide pH range of 5.0–9.0 and concentrations of 0.5–100 μM, with limits of detection reaching 0.13–0.18 and 0.13–0.19 μM, respectively. The microelectrode exhibited high selectivity, repeatability, and long-term stability for the detection of Ep and AAD. This method was successfully applied for the simultaneous detection of Ep and AAD in human blood and urine samples, with excellent recoveries of 92.9%–109.3% and 90.6%–107.6%, respectively.