Highly sensitive and selective detection of melamine in dairy products by turn-on fluorescence of ultrathin graphitic carbon nitride nanosheets

There is an important and realistic need to develop a practical sensor for melamine in dairy products that is highly sensitive and selective. However, the complicated composition and environment in milk necessitate the use of a stable luminophore as the sensor, as well as excellent photophysical properties. Here, ultrathin graphitic carbon nitride nanosheet (CNNS) was prepared by successive thermal polymerization and acid exfoliation. The photophysical properties of CNNS include its strong ultraviolet absorption and intense blue-light emission. Notably, CNNS could act as a chemo-sensor to detect trace melamine in dairy products. The high stability, eminent sensitivity, powerful selectivity, and competitiveness all substantiate the findings that this CNNS luminophore is a promising sensor for melamine in dairy products, and has potential practical value for monitoring milk quality.