The fabrication of N-doped carbon dots by methionine and their utility in sensing Cu 2+ in real water.

Copper ions (Cu) are ubiquitous in the ecosystem and cause serious environmental pollution, posing a threat to human health. Therefore, sensitive detection of Cu is urgently needed. Herein, we employed a solvothermal method to prepare blue-emitting carbon dots (Met-CDs) using formamide (FA) and methionine (Met) as precursors, with a high quantum yield (QY) of 38%. Based on the good optical stability of Met-CDs and selective quenching by Cu, a sensitive probe using Met-CDs for the detection of Cu in water was successfully designed. Within the linear range of 0.15-2 μM, the limit of detection (LOD) was determined to be as low as 47.7 nM, enabling the quantitative detection of Cu. Moreover, the recovery data of the spiked analysis of lake/river water samples were also satisfactory and verified the feasibility of the probe by the analysis of Cu in natural conditions.