“…Being time-consuming, these approaches also cannot be considered for in situ monitoring. As an alternative, spectroscopic techniques are being explored, as they offer a faster response and reasonable sensitivity, which makes them a suitable technological compromise. , Indeed, several optically responsive nanomaterials such as quantum dots, plasmonic nanoparticles, and fluorescent polymer dots were reported to effectively detect biological molecules. − Among various fluorescent nanomaterials, carbon dots (CDs) have demonstrated potential as sensing agents of metal ions due to their low photobleaching and good water solubility. ,− For example, it was revealed that fluorescent CDs can be used for the detection of Pd 2+ , Hg 2+ , Fe 2+ , and others. − The response of CDs to metal ions is generally monitored by measuring their fluorescence intensity. Furthermore, there are reports on fluorophore lifetime measurements for ion sensing.…”