Carbon Dots Based-on Polyethyleneimines as a Ratiometric Fluorescent Sensor of Morin

A blue-emitting carbon dots(CDs) based on polyethyleneimines(PEI) was prepared by hydrothermal synthesis method, which is applied to detect morin with a ratiometric fluorescence response. The detection method has very fast response speed, high selectivity and sensitivity, and strong anti-interference. The fluorescence emission of CDs is quenched and a new emission peak centered at 555 nm appears and enhances gradually in the presence of morin. The fluorescence intensity ratio of the new emission peak(555 nm) to the original emission peak(460 nm) increases linearly in the range from 1.0x10(-6) to 4.0x10(-5) mol/L. In particular, the ratio response is very sensitive with an extremely low detection limit of 3.0x10(-8) mol/L. The proposed probe shows no response to other commercial available flavonol with similar structure, common metal ions and amino acids, which indicates a high selectivity toward morin. In addition, the fluorescent color was changed from blue to yellow in the presence of morin, which displays a visual detection method. And the CDs can be applied to detect morin in diluted fetal calf serum either. Therefore, the present study supplies a cost-effective, fast and easily performed approach to detect morin with high selectivity and sensitivity.