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Gold nanoclusters (AuNCs) stabilized by glutathione (GSH) have been synthesized using a simple one-pot method, which were used as a fluorescence-enhanced probe for the detection of cysteine (Cys) and GSH. The detection is based on the finding that the weak yellow fluorescence of the AuNCs, with excitation/emission maxima of 430/600 nm, can be enhanced by Cys and GSH via NCs aggregation. This method is selective for Cys and GSH. According to the fluorescence enhancement, the detection ranges of AuNCs for Cys and GSH are 2.49 µM ~ 0.80 mM and 1.99 µM ~ 0.44 mM, with the detection limit of 0.42 µM and 0.27 µM, respectively. In addition, the probe has good anti-interference performance over other common biomolecules. Importantly, the probe is successfully used for the determination of Cys in human serum samples, displaying the potential application of the probe in the detection of biological sulfhydryl molecules in actual samples. [ABSTRACT FROM AUTHOR]

Graphene quantum dots (GQDs) as a new type of fluorescent carbon nanomaterials, showing excellent photoluminescence properties, biocompatibility, photoelectric properties, have become the current research focus. Iron element as an essential element in the human body and an important part of hemoglobin, is very important for human health, so the detection of ferric ions has great significance. In this paper, GQDs with strong blue light emission were prepared through pyrolysis treatment using citric acid as a carbon source. Through characterization by transmission electron microscopy (TEM) and fluorescence spectrometer, it was observed that the GQDs have a uniform particle size distribution and highly fluorescent intensity with a quantum yield of 27.4%. Due to the strong quenching effect of Fe3+ on GQDs fluorescence, GQDs was used as a green and facile fluorescence sensor to detect Fe3+ selectively and sensitively. The GQDs fluorescence sensor shows a sensitive response to Fe3+ in a wide linear range (3.5 × 10−6-6.7 × 10−4 M), a low detection limit of 1.6 μM (S/N = 3) and good selectivity. Importantly, the new sensor realizes the detection of Fe3+ ions in tap water because of its low detection limit, wide linear range, and high sensitivity. [ABSTRACT FROM AUTHOR]