Preparation of polyfluorinated azobenzene/niobate composite as electrochemical sensor for detection of ascorbic acid and dopamine

The polyfluorinated cationic azobenzene derivative, trans-[2-(2,2,3,3,4,4,4-heptafluorobutylamino)ethyl]-{2-[4-(4-hexyphenylazo)-phenoxy]ethyl}-dimethylammonium (abbreviated as C3F7-azo(+)Br(-)) was intercalated into layer semiconductor KNb3O8 by guest-guest exchange method to synthesize a sandwich-structured C3F7-azo(+)-Nb3O8 composite, which can be utilized as an electrochemical sensor for simultaneous detection of ascorbic acid (AA) and dopamine (DA). X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectrometer analysis (EDS) and Fourier transform infrared spectrometer (FTIR) were used to characterize the structure, morphology and composition of C3F7-azo(+)-Nb3O8. It is proposed that C3F7-azo(+) ions were intercalated into [Nb3O8](-) lamellar forming a bi-molecular layer at angle of 47.85 degrees. The results of cyclic voltammetry (CV) and differential pulse voltammetry (DPV) show that the as-prepared C3F7-azo(+)-Nb3O8/GCE can detect AA and DA simultaneously in N-2-saturated PBS (0.2 M, pH = 5.0), and the detection limits of AA and DA are 4.71 mu M and 1.81 mu M severally. Moreover, C3F7-azo(+)-Nb3O8/GCE has a long-term stability and good anti-interference capability.

Automated summary

A sandwich-structured composite material for simultaneous detection of ascorbic acid and dopamine was successfully synthesized by intercalating a polyfluorinated cationic azobenzene derivative into a layer semiconductor. The composite material exhibited good structural and compositional features, and showed effective detection of the target substances under saturated conditions.