Ratiometric fluorescence sensor based on carbon quantum dots for visual detection of hypochlorite ions

A ratiometric fluorescence sensor (c-CDs/Ru(bpy)(3)(2+)) based on the selective recognition of chitosan carbon dots (c-CDs) on ClO- and combine with Ru(bpy)(3)(2+) was established for sensitive and visual monitoring of hypochlorite ion (ClO-). Using this nanosensor, a highly sensitive assay of ClO- in the linear range of 0.026 - 70 mu M with a low detection limit (LOD) of 8.6 nM was provided by quenching the blue emission fluorescence. It is more attractive that ClO- can also be visualized by this nanosensor via evident color changes of the solution (from blue to red) under an ultraviolet (UV) lamp. In addition, since c-CDs and Ru(bpy)(3)(2+) have good water dispersibility and water solubility, respectively, the sensor can be applied to the detection of HClO in 100% aqueous solution. This is a new colorimetric and fluorescent dual-mode nanosensor with more simple preparation procedures, low cost, and excellent biocompatibility. It provides a new method for detecting ClO- and promotes the development of biosensing.