"Turn-on" fluorescent probes based on Rhodamine B/amino acid derivatives for detection of Fe3+ in water

Five kinds of Fe³⁺ fluorescent probes (RhB-Gly, RhB-Ala, RhB-Try, RhB-Cys, and RhB-His) were synthesized and characterized by NMR and mass spectrometry, based on the "OFF-ON" mechanism of Rhodamine B derivatives. The RhB-His based probe showed remarkable sensing performance toward the detection for Fe³⁺ and showed high selectivity for Fe³⁺ in the presence of other metal ions (such as Fe²⁺, Hg²⁺, Zn²⁺, Ba²⁺, Al³⁺, Co²⁺, Cd²⁺, K⁺, Na⁺, Mn²⁺, Pd²⁺, Pb²⁺, Ca²⁺, Ni²⁺, Cu²⁺, and Ag⁺), in PBS buffer solution (containing 2% of EtOH, pH 7.4, 1.0 mmol/L). The enhancement of the fluorescence was linearly proportional with the concentration Fe³⁺ (from 0 to 20 μmol/L), while the detection limit reached 0.88 μmol/L with a response time of 15 s. The RhB-His probe was successfully applied to investigate real samples and living cell imaging.

Chitosan–gold nanocomposite and its functionalized paper strips for reversible visual sensing and removal of trace Hg2+ in practice

To eliminate mercury contamination in aqueous environment, chitosan–gold nanocomposite and its functionalized paper strips were designed and developed for visual sensing and removal of trace Hg²⁺.

Preparation of polymethacrylate monolith modified with cysteine for the determination of Cr(iii) ions

In this study, a simple and rapid polymer monolith microextraction procedure was developed for the determination of Cr(iii) ions by inductively coupled plasma-atomic emission spectrometry. A monolithic column modified with cysteine was synthesized and characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermal gravimetric analysis, specific surface area analysis and pore size distribution analysis. The influences of analytical parameters such as sample pH, adsorption time, eluent type, and coexisting ions were examined. The limit of detection (LOD) and limit of quantification (LOQ) for Cr(iii) ions were 0.005 μg mL-1 and 0.017 μg mL-1, and the relative standard deviation (RSD) was 7.4% (n = 5). The prepared cysteine functionalized monolithic column displayed good enrichment capacity and was successfully applied to the determination of Cr(iii) ions in real samples.