Sulfur-doped graphitic carbon nitride nanosheets as a sensitive fluorescent probe for detecting environmental and intracellular Ag+

Silver is widely used in medical materials, photography, electronics and other industries as a precious metal. The large-scale industrial production of silver-containing products and liquid waste emissions aggravate the environmental pollution. Silver ion is one of the most toxic metal ions, causing pollution to the environment and damage to public health. Therefore, the efficient and sensitive detection of Ag+ in the water environment is extremely important. Sulfur-doped carbon nitride nanosheets (SCN Ns) were prepared by melamine and thiourea via high-temperature calcination. The morphology, chemical composition and surface functional groups of the SCN Ns were characterized by SEM, TEM, XRD, XPS, and FT-IR. The fluorescence of SCN Ns was gradually quenched as the Ag+ concentration increased. The detection limit for Ag+ was as low as 0.28 nM. The quenching mechanism mainly is attributed to static quenching. In this paper, SCN Ns were used as the fluorescent probe for detecting Ag+. SCN Ns have successfully detected Ag+ in different environmental aqueous samples and cells. Finally, SCN Ns were further applied to the visual quantitative detection of intracellular Ag+.

Automated summary

Silver is widely used as a precious metal in various industries, but its large-scale production and waste emissions contribute to environmental pollution. Efficient and sensitive detection of silver ions (Ag+) in the water environment is crucial. This study successfully detected Ag+ in different environmental water samples and cells using sulfur-doped carbon nitride nanosheets (SCN Ns) as a fluorescent probe.