▎ 摘　　要

A functional Ag-Fe3O4-grapheme oxide magnetic nanocomposite was synthesized and used to prepare a nitrite sensor. Morphology and composition of the nanocomposites were characterized by a transmission electron microscope, UV-VIS spectroscopy, X-ray diffraction, and Fourier transform infrared spectra. Electrochemical investigation indicated that the nanocomposites possess excellent electrochemical oxidation ability towards nitrites. The sensor exhibited two linear ranges: one from 0.5 mu M to 0.72 mM with a correlation coefficient of 0.996 and sensitivity of 1996 mu A mM(-1) cm(-2); the other from 0.72 mM to 8.15 mM with a correlation coefficient of 0.998 and sensitivity of 426 mu A mM(-1) cm(-2). The limit of detection of this sensing system was 0.17 mu M at the signal-to-noise ratio of 3. Additionally, the sensor exhibited long-term stability, good reproducibility, and anti-interference. (C) 2015 Institute of Chemistry, Slovak Academy of Sciences