On–Off–On Fluorescent Carbon Dot Nanosensor for Recognition of Chromium(VI) and Ascorbic Acid Based on the Inner Filter Effect

Chromium(VI) [Cr(VI)] is considered as a severe environmental pollutant, due to its highly toxic and carcinogenic properties. Therefore, low cost, highly sensitive sensors for the determination of Cr(VI) are highly demanded. It is well-known that highly luminescent carbon dots (CDs) have been successfully applied as fluorescent nanosensors for pH, ions, and molecular substances. In the present work, we have demonstrated an on-off fluorescent CD probe for detecting Cr(VI) based on the inner filter effect (IFE) because the absorption bands of Cr(IV) fully covered the emission and excitation bands of CDs. This CD-based nanosensor provides obvious advantages of simplicity, convenience, rapid response, high…