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A phenylamine-oligothiophene-based fluorescent sensor 2TBEA was reported. This sensor exhibited highly selective, sensitive and rapid detection of Hg 2 + ion in THF/H 2 O (7/3, v/v) solution through fluorescence quenching. The detection was unaffected by the coexistence of other competitive metal cations including Na + , K + , Ag + , Ca 2 + , Fe 3 + , Al 3 + , Co 2 + , Cu 2 + , Ni 2 + , Zn 2 + , Pb 2 + , Cd 2 + , Fe 2 + and Cr 3 + . A1:1 binding ratio for 2TBEA — Hg 2 + was demonstrated by Job's plot and mole-ratio curves. The coordination process was chemically reversible with EDTA. The detection limit was evaluated to be as low as 6.164 × 10 − 8 M. [ABSTRACT FROM AUTHOR]

A fast-responsive fluorescent phenylamine-oligothiophene sensor 3TDDA was reported. This sensor exhibited highly selective and sensitive detection of Hg 2 + ion in aqueous solution (THF/CH 3 CN/H 2 O, 45/50/5, v/v) through fluorescence quenching. The detection was not affected by the coexistence of other competitive metal ions such as Na + , K + , Ag + , Ca 2 + , Fe 3 + , Al 3 + , Co 2 + , Ni 2 + , Zn 2 + , Pb 2 + , Cd 2 + , Fe 2 + and Cr 3 + . A stoichiometric ratio (1:1) of the sensor and Hg 2 + was determined by a Job's plot and mole-ratio curves. The binding of sensor 3TDDA and Hg 2 + was also chemically reversible with EDTA. The detection limit was calculated as low as 4.392 × 10 − 7 M. [ABSTRACT FROM AUTHOR]

Single-layer graphene quantum dots are highly desirable while their facile and controllable preparations remain challenging. Herein, single-layered graphene quantum dots (sl-GQDs) were developed via a facile one-step hydrothermal synthesis, with citric acid and β-cyclodextrin (CD) as starting materials. The sl-GQDs decorated with CD molecules emit green fluorescence with a quantum yield of 5.34%, and exhibit a good response exclusively to ferric ions for their structural oxygenous groups. The linear range of the proposed sensor for ferric ions was found in a wide concentration range of 0–85 μM. The detection limit is about 0.26 μM. The sl-GQDs based sensing platform also demonstrates its feasibility in real water sample analysis with recoveries of 93.8%–101.5%. Image 1 • sl-GQDs were fabricated via a simple and eco-friendly hydrothermal route. • Functionalization and dispersion of CD inhibit π-π stacking of graphene sheets. • sl-GQDs contain abundant oxygenous groups and show high affinity for Fe3+. • sl-GQDs based sensor shows feasibility for tap water sample analysis. [ABSTRACT FROM AUTHOR]