Smartphone-assisted fluorescence sensor based on AuNCs/ZIF-8 for highly selective detection of Sb ions.

A novel smartphone-assisted fluorescence sensor was prepared for determination of antimony ions (Sb). It was synthesized by encapsulating glutathione (GSH)-decorated gold nanoclusters (AuNCs) into zeolitic imidazolate frameworks (ZIF-8) (denoted as AuNCs/ZIF-8). Based on the strong fluorescence quenching caused by the addition of Sb ions, the AuNCs/ZIF-8 was designed for determination of  Sb ions. The basic reason for fluorescence quenching of AuNCs caused by Sb ions is the reduction of Au (I) to Au (0), which is proved by the XPS. Mercury ions (Hg) and copper ions (Cu), the common interfering ions that can cause the strong quenching of AuNCs, can be masked by sodium borohydride (NaBH) and diethylene triamine pentaacetic acid (DTPA), respectively. Therefore, the prepared fluorescent sensor of AuNCs/ZIF-8 has high selectivity to the Sb ions. Under the optimal conditions, this proposed fluorescence sensor exhibited good linearity in the concentration range 1.25 × 10 to 7.5 × 10 M with a limit of detection of 3.13 × 10 M. Furthermore, this portable smartphone-assisted sensing platform based on AuNCs/ZIF-8 has the advantages of significant simplification and speeds of the operation process, which provides a new analytical method for real-time determination analysis of Sb ions in real samples.