Alkali metal (Na/ K) doped graphitic carbon nitride (g-C3N4) for highly selective and sensitive electrochemical sensing of nitrite in water and food samples

Abstract Herein alkali metal (Na/K) doped graphitic carbon nitride (g-C3N4) was fabricated using a facile one-pot route. The as synthesized three materials; bulk g-C3N4 (CN-B), K doped g-C3N4 (K-CN-300) and Na doped g-C3N4 (Na-CN-x) were well characterized using various characterization techniques. CN-B, K-CN-300 and Na-CN-x modified glassy carbon electrode were used as electrochemical nitrite sensor. Among them Na-CN-300 showcased impressive electrochemical current response under optimized condition. The Na doping into CN-B enhanced the electrochemical response of CN-B towards nitrite detection. The fabricated sensor exhibits excellent electrochemical performance and gave linear response for nitrite concentration range of 10 μM to 2 mM with LOD of 1.9 μM. Moreover the sensor displayed impressive selectivity, sensitivity and reproducibility, which are qualities of a good sensor material. In an attempt to fabricate disposable electrochemical sensor, Na-CN-300 was applied on a screen printed electrode and its stability was tested for 30 days. The proposed sensor was deployed for detection of nitrite in real samples (water and food), representing its possibilities for real-time analysis.