Targeted ginkgo kernel biomass precursor using eco-friendly synthesis of efficient carbon quantum dots for detection of trace nitrite ions and cell imaging

Carbon quantum dots (CQDs) are useful in medical imaging and detection of toxins in food. In this work, efficient CQDs are prepared from ginkgo kernels by a hydrothermal reaction. The size distribution of the CQDs is both uniform and narrow, with an average particle diameter of 2.7 nm. We realise a quantum yield of 37.8% from our CQDs. Moreover, the CQDs have high selectivity and sensitivity to NO 2 − , with the linear ranges of 0.50–50 μmol/L, and its limit of detection is 0.15 μmol/L, this developed method was applied to detect NO 2 − in corn sausage, ham sausage, preserved Szechuan pickle, and hot dog, whose concentration of nitrite were further confirmed by high performance liquid chromatograph. Furthermore, the as-prepared CQDs not only have low toxicity and benign biocompatibility, but also display strong blue fluorescence. Therefore, the CQDs can be used for cell imaging of MCF7 cells. Our results indicate that the proposed CQDs based on ginkgo kernel biomass have great potential for cell imaging and NO 2 − detection.