Electrochemical sensing of dopamine in the presence of serotonin using modified screen-printed carbon electrode

The Zr-based metal-organic framework (NH2-UiO-66(Zr))/graphene oxide (GO) nano­com­posite was synthesized via a simple approach and used as a voltammetric sensing platform. By integrating NH2-UiO-66 (Zr) with GO, the resulting nanocomposite exhibits superior sensor performance due to synergistic effects. The sensor was fabricated using a straightforward drop-casting method, where a suspension of NH2-UiO-66 (Zr)/GO was applied to a screen-printed carbon electrode (NH2-UiO-66 (Zr)/GO/SPCE). The NH2-UiO-66 (Zr)/GO/SPCE sensor was then employed to determine dopamine (DA) using differential pulse voltammetry (DPV). The NH2-UiO-66 (Zr)/GO/SPCE sensor demonstrated a linear response to DA over a concentration range of 0.001 to 800.0 µM, with a high sensitivity of 0.1002 µA µM-1. Using the DPV method, a limit of detection (LOD) of 0.5 nM was achieved. It was further employed as a sensing platform for the simultaneous detection of DA and serotonin (STN). The DA and STN peak separation were 245 mV. The NH2-UiO-66 (Zr)/GO/SPCE sensor was successfully used to analyse DA and STN in a human urine sample, achieving satisfactory recovery rates of 97.8 to 104.2 %.