Electrochemical Sensing of Dopamine with P-g-C₃N₄/ZIF-67/CPE Composite Electrodes

Dopamine is a key neurotransmitter and neuromodulator that regulates many critical brain functions. Accurate monitoring of its level is essential for neuroscience as well as the diagnosis and treatment of many brain diseases. In this work, we developed a new electrochemical sensor, comprising phosphorus-doped graphitic carbon nitride (P-g-C₃N₄) and zeolitic imidazolate framework 67 (ZIF-67), for dopamine detection. In this composite electrode material, ZIF-67 provides numerous adsorption and sensing sites, while P-g-C₃N₄ enhances overall electrical conductivity and stability. Cyclic voltammetry tests reveal the redox behavior of dopamine at the surface of the composite electrode across various pH values and scan rates. Using differential pulse voltammetry, the sensitivity and selectivity of this dopamine sensor were assessed, identifying a limit of detection of 0.39 nM. Further successful quantification of dopamine in urine samples suggests the potential practical use of this new composite electrochemical sensor for detecting dopamine and/or other neurotransmitters.