A bifunctional NiCo2S4/reduced graphene oxide@polyaniline nanocomposite as a highly-efficient electrode for glucose and rutin detection

A novel NiCo2S4/reduced graphene oxide@polyaniline (NiCo2S4/rGO@PANI) composite was synthesized by a facile two-step hydrothermal treatment and calcination, which was coupled with an in situ polymerization process. A bifunctional electrochemical sensor was developed for glucose electrocatalysis and rutin oxidation based on this composite modified glassy carbon electrode (GCE). The as-prepared composite was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FT-IR). Furthermore, the NiCo2S4/rGO@PANI/GCE composite displayed excellent electrocatalytic activity towards glucose in the linear range of 1-7000 M and a detection limit of 0.14 M (S/N = 3). And for rutin, the linear range was 0.01-200 M with a low detection limit of 0.007 M (S/N = 3). The sensitivity of this sensor for glucose and rutin was evaluated to be 4.924 and 75.50 A M-1 cm(-2), respectively. In addition, this sensor delivered high selectivity, good reproducibility, and long-term stability. The modified electrode was also employed to determine glucose in human blood serum samples and rutin in orange juice, buckwheat tea, and compound rutin tablet samples.