Facile preparation of orange-emissive carbon dots for the highly selective detection of silver ions

The importance of measuring the content of silver ions (Ag+) in aqueous solutions and biological samples has increased in recent years due to their very high toxicity to the environment and the human body. Orange-emissive carbon dots (CDs) were simply synthesized through the hydrothermal treatment of p-aminobenzoic acid and rho-aminophenol. The obtained CDs display orange fluorescence and stability, including favorable photostability, salt tolerance and water solubility. Significantly, the fluorescence intensity of the CDs was quenched by the addition of Ag+ via static quenching to form a nonfluorescent complex; thus a highly selective fluorescent method for the determination of Ag+ was developed. The present method showed a rapid response and excellent selectivity for Ag+ over other metal ions, and the relevant linear range and limit of detection were 5-100 M and 1.4 M, respectively. Furthermore, the practicability of this method was validated by the successful determination of Ag+ in water samples and a human serum sample. Compared with previous reports, this method showed rapid response and excellent selectivity, which present it as a valuable strategy in environmental protection and biological assays.