Glutathione stabilized green-emission gold nanoclusters for selective detection of cobalt ion

A glutathione stabilized Au nanoclusters (GSH-Au NCs) was synthesized here and used to selective detection of cobalt ion. The as-prepared GSH-Au NCs had strong green light emission around 500 nm, and the features of the NCs have been systematically characterized by UV–vis absorption, X-ray photoelectronic spectroscopic, Fourier transform infrared spectroscopy and transmission electron microscope characterization. The interactions between the GSH-Au NCs and metal ions was studied, and the results indicated that the fluorescence of the GSH-Au NCs could be quenched in the presence of Co 2+ ion at pH of 6.0. The quenching ratio was linear with the concentration of Co 2+ ions, and the calibration curve was I 0 /I  = 0.1187c co  + 0.6085 in the Co 2+ concentration ranges from 2.0 to 50.0 μM with correlation coefficient ( R 2 ) of 0.9950 and the limit of detection (LOD, 3 σ ) of 0.124 μM. In addition, we collected environmental water samples to test the reliability of the method and demonstrated this method is simple, rapid, and selective.