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 μM 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.