Nitrogen and phosphorus co-doped ratiometric fluorescent carbon dot as well as preparation method and application thereof

The invention provides a nitrogen-phosphorus co-doped ratiometric fluorescent carbon dot as well as a preparation method and application thereof. The preparation method of the carbon dot comprises the following steps: putting 1,8-diaminonaphthalene, phosphoric acid, formamide and secondary water into a hydrothermal reaction kettle together, and carrying out hydrothermal reaction; and centrifuging the obtained product, conducting filtering to remove insoluble substances, conducting dialyzing by using a dialysis bag to remove impurities, and conducting freeze-drying to obtain the nitrogen-phosphorus co-doped ratiometric fluorescent carbon dot. The preparation method is simple and low in cost, and the prepared nitrogen-phosphorus co-doped ratiometric fluorescent carbon dot can be used as a ratiometric fluorescent sensor for high-selectivity and high-sensitivity continuous detection of Mn (VII) and GSH in an aqueous solution, living cells and zebra fish. In addition, the prepared nitrogen-phosphorus co-doped rati