A novel near-infrared fluorescent sensor for zero background nitrite detection via the covalent-assembly principle

Different chemical states of nitrogen are present in many freshwater and marine ecosystems, and nitrite ions are one of the most toxic water-soluble nitrogen species. Developing an effective and convenient sensing method to constantly detect the concentration of nitrite has become a wide concern. Here, a novel near-infrared fluorescent probe (AAC) was designed and synthesized via the covalent assembly principle, showing excellent selectivity and high sensitivity for nitrite. A new nitrite-quantitative method was established with the help of AAC, and the detection limit of nitrite using the new method was as low as 6.7 nM. AAC was successfully applied for the quantitative detection of nitrite in real-world environmental and food samples (including river water and Chinese sauerkraut), and the detection results were essentially identical to the results obtained from the traditional Griess assay. Moreover, AAC was successfully applied for tracking nitrite in Escherichia coli by fluorescence imaging. Since nitrite can have devastating effects, the method established with AAC allowed us to see effectively about the water quality, food quality, etc.

Automated summary

A novel near-infrared fluorescent probe AAC with excellent selectivity and high sensitivity for nitrite was developed, allowing for the establishment of a new quantitative method with a detection limit as low as 6.7 nM. AAC was successfully applied for quantitatively detecting nitrite in real-world samples, showing consistent results with traditional methods.