Ligand-Induced Red-Emitting Copper Nanoclusters for Selective Fluorescence Determination of Aluminum Ions.

Monitoring levels of excessive aluminum ions (Al) is crucial as it can harm the immune system, reduce enzyme activity, cause cell death, and damage environmental and biological systems. Developing a fast and efficient Al ion determination method is the key to addressing this issue. In this work, red-emitting fluorescent copper nanoclusters (CuNCs) were synthesized using -acetyl-l-cysteine (NAC) as a ligand and CuCl·2HO through a facile procedure. The NAC-CuNCs exhibited a large Stokes shift and displayed remarkable luminescence properties. A method for detecting Al through a fluorescence probe was proposed. Its fluorescence mechanism was also explored. The probe showed rapid responsiveness (within 1 min) to Al ion determination. The detection limit for Al was found to be 19.7 nM, which is significantly lower than the WHO's value and most reports, with a linear range of 0-52.9 μM. The determination of Al concentrations in actual water using the fluorescence probe yielded satisfactory outcomes. Moreover, the visual detection of Al ions was also achieved through a smartphone, which can enhance its fast and practical detection.