Visualization and high sensitivity detection of Fe³⁺ and Cu²⁺ based on glutathione functionalized gold nanoclusters

In this paper, a glutathione functionalized gold nanocluster (GSH-AuNCs) was prepared. GSH-AuNCs can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide to produce a blue-green ox-TMB. By using its peroxidase activity and the GSH-AuNCs-TMB-H₂O₂ system, the visualization of Fe³⁺ and Cu²⁺ and the high sensitivity detection of Fe³⁺ and Cu²⁺ can be realized according to the change of absorbance value and color of the system. The results showed that the sensitivity of the system to detect Fe³⁺ and Cu²⁺ in industrial wastewater reached 1.25 × 10^-9 M and 1.25 × 10^-10M, respectively. At the same time, the chelating agents NH₄F and EDTA · 2Na were introduced to realize the selective detection of the two ions under the coexistence of Fe³⁺ and Cu²⁺ ions.