Green-Emitting Carbon Dots as Fluorescent Probe for Nitrite Detection

Abstract

Nitrite (NO2−) is a well-known inorganic pollutant in food and environment that can trigger severe environmental and healthy problems. Consequently, establishing accurate NO2− detection method is very important for food security, environment monitoring and human health. In this work, green fluorescent carbon dots (CDs) with a high fluorescence quantum yield (QY) of 36.13% are prepared for NO2− detection. The CDs are prepared by one-pot hydrothermal carbonization and polymerization of acriflavine. After carbonization, the anti-photobleaching property of CDs significantly enhanced compared to acriflavine. Under acidic conditions, the added of NO2− selectively induces the aggregation and fluorescence quenching of CDs. A good fluorescence linearity response in the range of 50 nM to 10 μM can be developed for NO2− quantitative analysis, with a detection limit of 11.6 nM. Owing to the diazotization reaction of NO2− and the phenylamine groups on the surface of CDs, this method shows excellent selectivity compared to common ions and amino acids. Furthermore, the proposed method shows favorable results in the detection of real water and Cantonese style sausage sample. This study provides a simple and efficient method for NO2− detection in food and environment.