Fluorescent Probe for Detection of Hg2+ and S2-Based on N-Doped Ti3C2 MXene Quantum Dots
A novel fluorescent"on-off-on"method for the detection of Hg2+ and S2-was developed based on N-doped Ti3C2 MXene quantum dots(N-Ti3C2 MQDs)and complexation.The prepared N-Ti3C2 MQDs emitted blue fluorescence(λem=440 nm)with a fluorescence quantum yield of 15.7%.Hg2+ can selectively coordinate with functional groups of—NH2,—COOH,and—OH on the surface of N-Ti3C2 MQDs through electrostatic interaction,resulting in fluorescent quenching of the N-Ti3C2 MQDs system.After the addition of S2-,HgS precipitation is formed due to the strong binding force between S2-and Hg2+,leading to the fluorescent recovery of the N-Ti3C2 MQDs.Based on this principle,a fluorescent"on-off-on"sensing method was constructed to quantitatively detect Hg2+ and S2-.The fluores-centy of the N-Ti3C2 MQDs probe is proportional to Hg2+ and S2-concentrations in the range of 0.02-200 μmol/L and 0.07-150 μmol/L,with a detection limit of 10 nmol/L and 30 nmol/L(S/N=3),respectively.This proposed method has the advantages of low cost,simple operation,high sensitivity,and good selectivity,which has been used for the determination of Hg2+ and S2-in real water samples.
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