Determination of Antimony(III) by Differential Pulse Voltammetry Using a Gold Nanoparticle–Ionic Liquid–Graphene-Modified Selenium-Doped Carbon Paste Electrode

Smartphone-assisted fluorescence sensor based on AuNCs/ZIF-8 for highly selective detection of Sb3+ ions

A novel smartphone-assisted fluorescence sensor was prepared for determination of antimony ions (Sb3+). 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 Sb3+ ions, the AuNCs/ZIF-8 was designed for determination of  Sb3+ ions. The basic reason for fluorescence quenching of AuNCs caused by Sb3+ ions is the reduction of Au (I) to Au (0), which is proved by the XPS. Mercury ions (Hg2+) and copper ions (Cu2+), the common interfering ions that can cause the strong quenching of AuNCs, can be masked by sodium borohydride (NaBH4) and diethylene triamine pentaacetic acid (DTPA), respectively. Therefore, the prepared fluorescent sensor of AuNCs/ZIF-8 has high selectivity to the Sb3+ ions. Under the optimal conditions, this proposed fluorescence sensor exhibited good linearity in the concentration range 1.25 × 10-8 to 7.5 × 10-4 M with a limit of detection of 3.13 × 10-9 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 Sb3+ ions in real samples.

A simple graphene modified electrode for the determination of antimony(III) in edible plants and beverage

Antimony(III) is a rare electroactive specie present on Earth, whose concentration is not typically determined. The presence of high concentrations of antimony is responsible for a variety of diseases, which makes it desirable to find convenient and reliable methods for its determination. We have developed a convenient glassy carbon modified electrode with electroreduced graphene oxide GC/rGO for the first time determination of Sb(III) in commercial lettuce, celery, and beverages. The surface of the electrode was characterized by scanning electron microscopy (SEM) and cyclic voltammetry, indicating a heterogeneous and rough surface with a real area of 0.28 cm², which is ~2.5 times the area of GC. The optimal chemical and electrochemical parameters used were: sodium acetate buffer (pH = 4.3), an accumulation potential of -1.0 V and an accumulation time of 150 s. The analytical validation was developed evaluating the linear range (10-60 µg L^-1), limit of detection (2.5 µg L^-1), accuracy, repetibility and reproducibility with satisfactory results (relative standard deviation (RSD) values lower than 10%). All the analyzes performed in real samples by stripping voltammetry were compared with GF-AAS, showing statistically similar values, demonstrating that GC/rGO could be effectively applied in the analysis of food samples.