Fluorescent Determination of Mercury(II) Using Rhodamine B Immobilized on Polystyrene Microspheres

Preparation of chitosan-coated polystyrene microspheres for the analysis of trace Pb(ii) ions in salt by GF-AAS assisted with solid-phase extraction

Chitosan-coated polystyrene solid-phase extraction fillers.

Comparison of two rhodamine-based polystyrene solid-phase fluorescent sensors for mercury(II) determination

Two novel rhodamine-based polystyrene solid-phase fluorescent sensors PS-AC-I and PS-AC-II with different coordination atoms (O or S) are synthesized and shown to be able to detect Hg(II) ions. They are characterized by Fourier-transform infrared spectroscopy and by scanning electron microscopy analysis. Their fluorescent properties, including response time, pH effects, fluorescence titrations, metal ion competition and recycling, are investigated and compared. Sensor PS-AC-II displayed higher selectivity and sensitivity to Hg(II), with a lower detection limit of 0.032 µM, which was 15 times better than PS-AC-I. A detection mechanism involving the Hg(II) chelation-induced ring-opening of the rhodamine spirolactam is proposed with the aid of theoretical calculations.

Synthesis, structure-fluorescence relationships and density functional theory studies of novel naphthalimide-piperazine-pyridine-based polystyrene sensors for Hg(ii) detection

Two novel naphthalimide-piperazine-pyridine-based polystyrene solid-phase fluorescent sensors PS-NA and PS-ND with different lengths of the linker were synthesized and shown to be able to detect Hg(ii) ions. Their structures were characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) analysis. Fluorescence properties, including response time, pH effects, fluorescence titration, metal ion selectivity and regeneration, were investigated and compared. Sensor PS-NA displayed a higher fluorescence response to Hg(ii) than PS-ND, with a lower detection limit of 1.01 μM. The detection mechanism involving the Hg(ii) chelation-induced photo-induced electron transfer (PET) was proposed with the aid of density functional theory (DFT) calculations. Sensors PS-NA and PS-ND with seven other similar sensors from our previous studies were collected together for thorough structure-fluorescence relationship (SFR) studies. Sensor PS-NA being recyclable and environmentally friendly was successfully employed in the fluorescence detection of Hg(ii) in real water samples, indicating its good potential in practical application.

Fluorescent difference between two rhodamine-PAHs polystyrene solid-phase sensors for Hg(II) detection based on crystal structure and density functional theory calculation

Two novel rhodamine-polystyrene solid-phase fluorescence sensors PS-RB-2 and PS-R6G-2 with pyrene or naphthalene as fluorophore were synthesized for Hg(II) detection. Their structures were characterized by Fourier transform infrared (FTIR) spectra and scanning electron micrographs (SEM). Sensor PS-RB-2 displayed higher selectivity and sensitivity to Hg(II), with a lower detection limit of 0.065 μM. A detection mechanism involving the Hg(II) chelation-induced spirocycle open of rhodamine was proposed and discussed from theoretic level based on crystal structures and density functional theory (DFT) calculations. Sensor PS-RB-2 with recyclable and environment-friendly performance was successfully employed to fluorescent detection of Hg(II) in real water and fish samples, indicating its good potential in practical application. Its solid phase extraction columns were developed for rapid detection of Hg(II) by observing the color change with the naked eyes.