Immobilization of gold nanoclusters inside porous electrospun fibers for selective detection of Cu(II): A strategic approach to shielding pristine performance.

Here, a distinct demonstration of highly sensitive and selective detection of copper (Cu(2+)) in a vastly porous cellulose acetate fibers (pCAF) has been carried out using dithiothreitol capped gold nanocluster (DTT.AuNC) as fluorescent probe. A careful optimization of all potential factors affecting the performance of the probe for effective detection of Cu(2+) were studied and the resultant sensor strip exhibiting unique features including high stability, retained parent fluorescence nature and reproducibility. The visual colorimetric detection of Cu(2+) in water, presenting the selective sensing performance towards Cu(2+) ions over Zn(2+), Cd(2+) and Hg(2+) under UV light in naked eye, contrast to other metal ions that didn't significantly produce such a change. The comparative sensing performance of DTT.AuNC@pCAF, keeping the nonporous CA fiber (DTT.AuNC@nCAF) as a support matrix has been demonstrated. The resulting weak response of DTT.AuNC@nCAF denotes the lack of ligand protection leading to the poor coordination ability with Cu(2+). The determined detection limit (50 ppb) is far lower than the maximum level of Cu(2+) in drinking water (1.3 ppm) set by U.S. Environmental Protection Agency (EPA). An interesting find from this study has been the specific oxidation nature between Cu(2+) and DTT.AuNC, offering solid evidence for selective sensors.