Electrocatalytic oxidation of nitrite using metal-free nitrogen-doped reduced graphene oxide nanosheets for sensitive detection

•Nitrogen-doped reduced graphene oxide (NrGO) materials were prepared.•Metal-free NrGO-modified electrode for electrocatalytic oxidation of nitrite.•Sensitive nitrite detection with wide response range and low detection limit.•Practical detection of nitrite in pickled garlic with the electrochemical sensor.

Nitrite can become poisonous to animals and human beings as it can lead to generation of carcinogenic N-nitrosamines. Metal-free nitrogen-doped reduced graphene oxide (NrGO) exhibited a good electrocatalytic activity toward oxidation of nitrite with the relatively low oxidation potential of 0.68 V (v.s. saturated calomel electrode), thus, a facile electrochemical sensor based on metal-free NrGO was fabricated for sensitive detection of nitrite for the first time. The novel sensor showed a wide linear concentration range from 0.5 to 5000 μM and a low detection limit of 0.2 μM at the signal-to-noise ratio of 3 with good selectivity, stability, and reproducibility. This fabricated sensor was used for the determination of nitrite in pickled garlic and river water. These results demonstrate that the facile metal-free NrGO-modified electrochemical sensor has promising applications for the determination of nitrite in food and environment.

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