Multifunctional synergistic action of metal-organic framework composites enhance the electrochemical detection sensitivity of dopamine.

Metal-organic frameworks (MOFs) have shown major promise for electrochemical dopamine (DA) sensing owing to their high surface area, tunable pores, and abundant active sites. In this work, iron-tetra(4-carboxyphenyl)porphyrin-coordinated assembly metal-organic framework (Fe-TCPP MOF material) capable of effectively catalyzing the oxidation of DA was synthesized. Subsequently, it was combined with reduced graphene oxide (rGO) with excellent electrical conductivity and perfluorosulfonic acid polymer (Nafion) with cation selectivity to construct an electrochemical sensor that could synergistically enhance the sensitivity of DA detection. The resulting Fe-TCPP/rGO/Nafion electrode detected DA from 0.1 to 3200 μM with a detection limit of 0.021 μM, outperforming most reported sensors. It also maintained high stability, selectivity, and interference resistance over repeated cycles, and achieved recoveries of 84.84-110.76% in real samples. Mechanistically, the porous Fe-TCPP MOF increased accessibility of catalytic sites; rGO improved charge transport and π-π adsorption; and Nafion provided cation-exchange selectivity and electrostatic preconcentration. These complementary roles yielded synergistic gains in catalytic oxidation, preconcentration, selectivity, and anti-interference. The integrated strategy offered a practical route to high-performance MOF-based DA sensors and a useful reference for developing efficient analytical materials.