Quantitative detection of nitrite with N-doped graphene quantum dots decorated N-doped carbon nanofibers composite-based electrochemical sensor

Herein, we firstly report a novel N-doped graphene quantum dots decorated N-doped carbon nanofibers (NGQDs@NCNFs) composite and its application to construct highly sensitive electrochemical sensor for nitrite determination. The NGQDs@NCNFs composite was prepared by combining electrospinning, carbonization and a facile route of one-step hydrothermal method. The as-prepared composite possessed free-standing film structure and high flexibility, which was favorable for electrode modification. NGQDs successfully grafted on the surface of NCNFs, thus avoiding the large aggregation and maintaining the large electroactive surface area of NGQDs. While the NCNFs acted as a novel support for NGQDs attachment and benefited fast electron transfer. The electrocatalytic performance of the NGQDs@NCNFs composite was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy. It is revealed that the electrochemical nitrite sensor developed based on the novel NGQDs@NCNFs composite exhibited superior analysis performance to previously reported nitrite sensors, such as wide linear range (5-300 mu M, R-2 = 0.999; 400-3000 mu M, R-2 = 0.997), low detection limit (3 mu M), excellent reproducibility and selectivity, and good testing recoveries for the detection of nitrite present in sausage, pickle, lake water and tap water. These results suggest that NGQDs@NCNFs composite could be a promising and convenient material for the fabrication of electrochemical sensors. (C) 2017 Elsevier B.V. All rights reserved.