Iodine stimulated “in-situ” growth of His/GSH-AuNCs for the detection of iodine ions via ratiometric fluorescence

As one of the most indispensable microelements in living organisms, the quantitative detection of iodine is of great significance in the fields of food and life sciences. Herein, a novel ratiometric fluorescent probe His/GSH-AuNCs was developed for the detection of iodide ions. The His/GSH-AuNCs, which can be readily obtained by mixing histidine-stabilized gold nanoclusters (His-AuNCs) and glutathione-stabilized gold nanoclusters (GSH-AuNCs) in an appropriate proportion, have two distinct intrinsic emission peaks at 470 nm and 620 nm when excited at 340 nm. Significantly, the His/GSH-AuNCs could precisely and sensitively capture I − in complex environments via its “in-situ” growth stimulated by iodine. Meanwhile, the fluorescence intensity of two emission peaks of His/GSH-AuNCs was hindered to varying degrees. Based on the different variations of these two emission peaks, a ratiometric fluorescence method was established with the relationship between the variation of the ratio of two emission peaks ((I 470 /I 620 )/(I 470 /I 620 ) 0 ) and the I − concentration. Furthermore, the detection mechanism was investigated by employing a combination of UV–vis and TEM techniques. Moreover, the His/GSH-AuNCs probe has been successfully applied to monitor iodide ions in environmental water samples, tap water samples, and urine samples.