Controlled chitosan coated Prussian blue nanoparticles with the mixture of graphene nanosheets and carbon nanoshperes as a redox mediator for the electrochemical oxidation of nitrite

The graphene nanosheets and carbon nanospheres mixture (GNS–CNS) was prepared by electrolyzing graphite rob in KNO3 solution under a constant current. The cationic chitosan (CS) coated Prussian blue (PB) as an efficient redox mediator could interact with the anion GNS–CNS via electrostatic interaction. The synergy effect of CS@PB nanoparticles and GNS–CNS contributed to the excellent electrochemical response towards the nitrite oxidation. The as-prepared CS@PB/GNS–CNS modified glass carbon (GC) electrode demonstrated its high sensitivity, low detection limit, short response time, and wide concentration range for the nitrite detection.