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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