Highly sensitive carbon dots fluorescent probe with ratiometric emission for the determination of ClO

A rising ratiometric fluorescent N, S co-doped carbon dots (N, S-CDs) probe for ClO- had been facilely obtained via one step hydrothermal method. The N, S-CDs revealed dual emission at 478 and 552 nm with the excitation of 377 nm. The intensity of fluorescence at 478 nm kept unchanged and fluorescence at 552 nm quenched dramatically in the presence of ClO-. The corresponding fluctuation of color occurred from yellow to blue upon exposure to a UV lamp. Oxidation reaction of functional groups on the surface of N, S-CDs resulted in this evident quenching. The highly N, S-CDs ratiometric fluorescent probe exhibited excellent sensitivity and selectivity towards ClO-. The quantitative analysis of ClO- displayed a linear range of 0.067-60 μmol/L with a detection limit of 9.1 nmol/L (S/N=3). Furthermore, we provided applications of N, S-CDs as the paper-based fluorogenic devices for the fast and easy sensing of ClO-. The ratiometric fluorescent probe could be also further adopted to cellular imaging in terms of low toxicity, good water solubility and biocompatibility, which demonstrated great potential in biosensing and bioimaging.