Facile preparation of amino-carbon dots/gold nanoclusters FRET ratiometric fluorescent probe for sensing of Pb2+/Cu2+

Abstract

Ratiometric fluorescent probes could eliminate the influence from experimental factors and improve the detection accuracy. In this work, under mild conditions, through the electrostatic attraction between positively charged amino-carbon dots (N-CDots) and negatively charged gold nanoclusters (AuNCs), a novel Förster resonance energy transfer (FRET) ratiometric fluorescent probe was fabricated for reliable, selective, and sensitive sensing of Pb2+ and Cu2+. The as-prepared probe shows dual emission peaks at 440 nm and 565 nm with efficient FRET under a single excitation wavelength of 380 nm. The red fluorescence of AuNCs is enhanced by Pb2+ and quenched by Cu2+, while the blue fluorescence of N-CDots stay stable, resulting in fluorescent ratiometric changes. With this strategy, the probe was successfully applied to detect Pb2+ or Cu2+ in real water samples with satisfactory recoveries at three spiking levels ranging from 94 to 104%. Moreover, it could realize the visual semi-quantitative determination of these two heavy metal ions by naked eyes. The good results imply that the developed N-CDots/AuNCs probe is conducive to Pb2+ or Cu2+ determination and possesses the great application potential for water-quality monitoring.