Photoluminescence Determination of Aluminum Using Glutathione-Capped Gold Nanoclusters

Aluminum is a common metal that is used extensively in daily life. However, over-exposure to aluminum may result in nervous systemrelated diseases. Thus, it is important to develop a rapid sensing method that can be used to screen samples. In this study, glutathione-capped gold nanoclusters with bright photoluminescence were demonstrated to be effective sensing probes for aluminum ions. The photoluminescence of glutathione-capped gold nanoclusters was enhanced in the presence of aluminum ions. The results show that glutathione-capped gold nanoclusters selectively determined aluminum ions in samples prepared in aqueous ammonium acetate buffer (pH 5.5). The acetate maintains the pH and serves as a chelating agent to interact with non-analyte metal ions. Therefore, other metal ions have little effect on the photoluminescence of the glutathione-capped gold nanoclusters. The photoluminescence of the glutathione-capped gold nanoclusters was switched on in samples containing aluminum ions. The selective sensing was based on chelation between the aluminum ions and ligands on the surface of the glutathione-capped gold nanoclusters. The limit of detection was estimated to be as low as approximately 100 nM. The method was used to determine the concentration of aluminum ions in lake water and soil extracts.