Carbon quantum dots for fluorescent detection of nitrite: A review

NO2- is commonly found in foods and the environment, and excessive intake of NO2- poses serious hazards to human health. Thus, rapid and accurate assay of NO2- is of considerable significance. Traditional instrumental approaches for detection of NO2- faced with limitations of expensive instruments and complicated operations. Current gold standards for sensing NO2- are Griess assay and 2,3-diaminonaphthalene assay, which suffer from slow detection kinetics and bad water solubility. The newly emerged carbon quantum dots (CQDs) exhibit integrated merits including easy fabrication, low-cost, high quantum yield, excellent photostability, tunable emission behavior, good water solubility and low toxicity, which make CQDs be widely applied to fluorescent assay of NO2-. In this review, synthetic strategies of CQDs are briefly presented. Advances of CQDs for fluorescent detection of NO2- are systematically highlighted. Lastly, the challenges and perspectives in the field are discussed.