3D nitrogen-doped graphite foam@Prussian blue: an electrochemical sensing platform for highly sensitive determination...

A platform is described for voltammetric sensing of hydrogen peroxide (H₂O₂). It is based on the use of nitrogen-doped graphite foam modified with Prussian Blue particles (PB/NGF). Graphite foam was synthesized by chemical vapor deposition, and doping with nitrogen was realized via dielectric barrier plasma discharge. PB particles were grown on the NGF through electrodeposition. SEM images of NGF verified the porous and interconnected structure of graphite foam, and XPS and Raman spectroscopy verified the successful doping with N. The performance of the PB/NGF electrode was characterized by CV and EIS which showed it to possess outstanding properties in terms of sensing H₂O₂. H₂O₂ was quantified in a range of 0.004 to 1.6 mM with a detection limit of 2.4 μM. The PB/NGF electrode also is shown to be a viable substrate for loading glucose oxidase (GOx). The GOx-functionalized electrode responds to glucose over the 0.2 to 20 mM concentration range at a potential of -50 mV (vs. Ag/AgCl), with a sensitivity of 27.48 mA M^-1 cm^-2 and a 0.1 M detection limit (at an S/N ratio of 3). The glucose sensor is selective, stable, and reproducible. The biosensor was successfully applied to the determination of glucose in spiked human serum samples, and this confirmed it practicability. Graphical abstract Schematic of a self-supporting amperometric glucose biosensor based on glucose oxidase and Prussian blue modified 3D nitrogen doped graphite foam.