Electrochemical sensing platform based on fluorine-containing porphyrin conjugated polymers for simultaneous detection of dopamine and uric acid detection

The design of a highly efficient non-enzymatic electrochemical sensor capable of simultaneously detecting dopamine and uric acid is of significant importance to biomedical research, particularly in disease diagnosis and health monitoring. However, due to the similar oxidation potentials of dopamine and uric acid and often coexist with other interferents, conventional electrode materials still face considerable challenges in achieving selective detection of these two analytes. In this work, we endeavor to design a highly selective porphyrin polymer-modified electrode material for the parallel sensing of dopamine and uric acid. First, through DFT calculations, we demonstrated that the adsorption energies of dopamine and uric acid to the two porphyrin monomers in the fluorinated porphyrin conjugated polymer (FeFe-F PCP) are significantly higher compared to those in non-fluorinated porphyrin conjugated polymer (FeFe PCP). Based on this, we further synthesized the FeFe-F PCP by employing a Pd-/CuI-catalyzed Sonogashira coupling reaction between ferrum (II) 5,10,15,20-tetrakis(4-bromophenyl)porphyrin (FePorBr) and ferrum (II) 5,15-di(4-ethynylphenyl)-10,20-diphenylporphyrin (FePor-F), and characterized the resulting material. Subsequently, FeFe-F PCP was employed to modify a GCE for the sensitive and selective sensing of dopamine and uric acid, as well as their simultaneous analysis in biological samples. In individual detection assays, the FeFe-F PCP/GCE effectively detected dopamine and uric acid, achieving linear detection ranges of 1 μM–100 μM and 0.1 μM–80 μM, respectively. The sensor demonstrated low detection limits of 0.16 and 0.03 μM for dopamine and uric acid, correspondingly. Furthermore, simultaneous detection of dopamine and uric acid was achieved within a linear range of 3 μM–100 μM. The developed sensor demonstrated excellent stability, reproducibility, and sensitivity, with low detection limits of 0.33 and 0.30 μM for dopamine and uric acid, respectively. The sensor has been successfully used to detect dopamine and uric acid in human urine samples with recoveries of 98.0%–102.4%, which has great potential for practical applications.