Fast and accurate detection of aqueous contaminants is of significant importance as these contaminants raise serious risks for human health and the environment. Lead ion and its compounds are highly toxic and can cause various illnesses. Thus, developing a simple, inexpensive and rapid method to detect Pb2+ with sensitivity and selectivity in real samples at a very low concentration is of high importance. Graphene quantum dots (GQDs) are single or few-layer graphenes with a tiny size of only several nanometers, it possesses some excellent characteristics, such as chemical stability, excellent water solubility and suitability. GQDs and their chemical derivatives have received more attention, as their diameters are mainly distributed in a larger range. Importantly, the carboxylic acid moieties at the edge of GQDs makes it easy to function with various organic, polymeric, inorganic or biological species. In this work, we synthesized a novel GQD-derived composite, i.e. 3,9-Dithia-6-monoazaundecane (DMA) functionalized GQDs (GQD-DMA), using DMA functionalized graphene oxide (GO-DMA) based on hydrothermal method. Moreover, combined with unique properties of as-prepared GQD-DMA and the natural fluorescence of tryptophan, we developed a selective and sensitive strategy for detecting Pb2+ with high sensitivity and selectivity based on GQD-DMA/tryptophan compound system. The detection limit of 9 pM is much lower than most of the previously reported sensors to the best of our knowledge. In addition, we have applied this method to the detection of lead ions in the striatum of rat, combined with microdialysis sampling in vivo and achieved convinced results successfully. We believe it may have general implications in the biological and environmental fields.

Highly sensitive and selective fluorescent probe for cerebral lead ions based on GQD-DMA/tryptophan compound system

247th National Meeting (2014)

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