One minute synthesis of green fluorescent copper nanocluster: The preparation of smartphone aided paper-based kit for on-site monitoring of nanomolar level mercury and sulfide ions in environmental samples

We wish to report, a minute synthesis of green fluorescent copper nanocluster by simple sonication. 1-thio-beta-D-glucose was used as a capping ligand to synthesis copper nanocluster (TG-CuNCs). The TG-CuNCs exhibit the emission maximum at 430 nm. The synthesized TG-CuNCs was well characterized by UV-vis, fluorescent, XRD, HR-TEM and FT-IR techniques. After the addition of Hg2+ or S2- into TG-CuNCs, the fluorescence was quenched. Based on the quenching of fluorescence, we have calculated the detection limit 1.7 nM and 1.02 nM for Hg2+ and S2-, respectively. Finally, we have applied TG-CuNCs for the detection of Hg2+ and S2- in tap, river, pond water. Importantly, the smartphone aided paper-based kit was developed for on-site monitoring of Hg2+ and S2- ions. To the best of our knowledge, this is the first report for the one-minute synthesis of TG-CuNCs and the preparation of smartphone aided paper-based kit for on-site monitoring of Hg2+ and S2- ions. Further, it is anticipated that this synthesis of TG-CuNCs and smartphone aided paper-based kit for Hg2+ and S2- will be useful materials in the filled with the biosensor, material science and nanotechnology.