▎ 摘　　要

A sensitive and selective electrochemical sensor based on carboxyl graphene (CG), polypyrrole (PPy), and chitosan (CS) nanocomposite-modified glassy carbon electrode (GCE) has been developed for nitrite determination. The electrochemical performances of CG/PPy/CS/GCE were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Under the optimum experimental conditions, CG/PPy/CS/GCE exhibited excellent differential pulse voltammetry (DPV) response of nitrite. A linear relationship between DPV peak current and the concentration of nitrite was obtained in the range of 0.2 to 1000 mu M. The limit of detection of nitrite was estimated to be 0.02 mu M. Using such modified electrodes, our method is quite reproducible for nitrite determination, even for real water samples.