A FRET Fluorescent Sensor for Ratiometric and Visual Detection of Sulfide Based on Carbon Dots and Silver Nanoclusters.

Abstract

In this work, the fluorescent sensor based on fluorescence resonance energy transfer (FRET) and electrostatic interaction (EI) was prepared for the ratiometric and visual detecting S2-. The FRET fluorescent sensor consists of two fluorophores, with carbon dots (CDs) as energy donors and silver nanoclusters (Ag NCs) as acceptors. At 390nm excitation, CDs and Ag NCs showed two well-separated peaks at 445nm and 660nm, separately. The existence of S2- caused the red fluorescence at 660nm to be quenched, whereas the blue fluorescence at 445nm was restored, and the fluorescence color of the ratiometric sensor changed from pink to blue. It could be employed in ratiometric and visual detecting S2-. The linear range of quantitative detection S2- was 0.5-100μM, and its detection limit was 0.35μM. CDs-Ag NCs could be used for detecting S2- in mineral water and tap water. The results showed that the FRET ratiometric fluorescent sensor exhibits good anti-interference and high selectivity for detecting S2- in environmental water samples.