An inorganic base stripping approach to synthesize N-doped Ti3C2 quantum dots as fluorescence nanoprobe for the simultaneous detection of Co2+ and Ag+ ions

• A simple inorganic base stripping strategy to synthesize N-Ti 3 C 2 QDs. • N-Ti 3 C 2 QDs possessed strong high FL emission with high QY of 14.46%. • N-Ti 3 C 2 QDs had good salt stability and oxidation resistance. • N-Ti 3 C 2 QDs as FL probe for the simultaneous detection of Co 2+ and Ag + ions. N-doped Ti 3 C 2 quantum dots (N-Ti 3 C 2 QDs) as the fluorescent nanoprobe were synthesized through inorganic base (i.e. KOH) stripping and solvothermal approach. The N-Ti 3 C 2 QDs displayed well-monodispersed near-spherical particles with average size of 2.3 nm, exhibited brightly blue emission and good stability, and possessed 14.46% of fluorescent quantum yield. Upon addition of Co 2+ or Ag + ions, the fluorescence (FL) of N-Ti 3 C 2 QDs could be quenched significantly. Mechanism investigation indicated that the inner filter and static extinguishing effects are responsible for the Co 2+ or Ag + ions induced FL quenching of the N-Ti 3 C 2 QDs. Based on above outcomes, we developed a simple N-Ti 3 C 2 QDs based fluorescent assay for the simultaneous determination of Co 2+ and Ag + ions, with a low detection limit of 0.21 and 0.10 μM, respectively. The assay was used to determine the content of Co 2+ and Ag + in real samples. This work will provide another way for the synthesis of fluorescent N-Ti 3 C 2 QDs and exploited their application in simultaneous detection of Co 2+ and Ag + .