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Highly sensitive and selective fluorescence sensing and imaging of Fe3+ based on a novel nitrogen-doped graphene
Dongming Wu1, Chaojie Qu1, Jizhong Wang2
1Green Catalysis Center of Zhengzhou University, College of Chemistry, Henan Joint International Research Laboratory of Green Construction of Functional Molecules and Their Bioanalytical Applications, Zhengzhou Key Laboratory of Functional Nanomaterial and Medical Theranostic, Zhengzhou University, Zhengzhou, China.
Abstract:
A novel nitrogen-doped graphene quantum dots (N-GQDs) with a green fluorescence emission was synthesized through microwave method using citric acid and semicarbazide hydrochloride as reactants. The as-synthesized N-GQDs exhibited good stability, excellent water solubility, and negligible cytotoxicity. Due to intermolecular charge transfer, ferric ion (Fe3+ ) has a strong quenching effect on the N-GQDs. Fluorescence quenching has a linear relationship with the Fe3+ concentration in the range 0.02-12 μM. The detection limit was 1.43 nM. What is more, it is worth mentioning that the obtained N-GQDs showed high selectivity and sensitivity towards Fe3+ . Under the optimum conditions, the addition of 10-fold copper ions and 100-fold other metal ions had no influence on the detection of Fe3+ (0.8 μM), which indicated a higher sensitivity compared with that of the reported methods. Due to their excellent properties, the obtained N-GQDs was successfully applied for sensing and imaging Fe3+ in water samples and HeLa cells.
