Ratiometric fluorescent sensing of mercury (II) ion based on the Pt nanozyme-triggered fluorescence resonance energy transfer between Si quantum dots and 2,3-diaminophenazine

The demand for efficient methods to determine mercury ion (Hg2+) is increasing. Herein, we developed a ratiometric fluorescence assay by the coupling of nanozyme and fluorescence resonance energy trans-fer (FRET) to determine Hg2+. Platinum nanoparticles (PtNPs) was synthesized as effective nanozyme to catalyze the oxidation of o-phenylenediamine (OPD) at the presence of hydrogen peroxide (H2O2) to pro-duce 2,3-diaminophenazine (DAP). The fluorescence emission of Si quantum dots (QDs) at 414 nm (I414) was observed to be quenched by DAP (emission at 576 nm (I576)) via FRET mechanism, whereas Hg2+ can depress the catalytic activity of PtNPs to generate DAP. Based on this principle, SiQDs/PtNPs/OPD/H2O2-based ratiometric fluorescence assay was developed that the emission ratio of DAP and SiQDs (I-576/I-414) decreased with a higher concentration of Hg2+. Noteworthy, the sensitivity of such system was found to be related with the value of I-576/I-414. The developed assay offered a detection range of 20-3000 nM and a detection limit of 10.5 nM. This assay was applied to analyze Yangtze river water, and its reliability has been validated by the standard ICP-MS method. Our work provided an effective and convenient method for Hg(2+)detection. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study developed a ratiometric fluorescence assay using nanozyme and fluorescence resonance energy transfer to efficiently detect mercury ion, which was validated for its reliability in Yangtze river water samples.