Turn-On and Near-Infrared Fluorescent Sensing for 2,4,6-Trinitrotoluene Based on Hybrid (Gold Nanorod)−(Quantum Dots) Assembly

摘要

ABSTRACT: In this study, we design a FRET system consistingnof gold nanorod (AuNR) and quantum dots (QDs) for turn-onnfluorescent sensing of 2,4,6-trinitrotoluene (TNT) in near-infrarednregion. The amine-terminated AuNR and carboxyl-terminatednQDs first forma compact hybrid assembly through amine-carboxylnattractive interaction, which leads to a high-efficiency (>92%)nFRET from QDs to AuNRs and an almost complete emissionnquenching. Next, added TNT molecules break the preformednassembly because they can replace the QDs around AuNRs, based on the specific reaction of forming Meisenheimer complexesnbetween TNT and primary amines. Thus, the FRET is switched off, and a more than 10 times fluorescent enhancement is obtained.nThe fluorescence turn-on is immediate, and the limit of detection for TNT is as low as 0.1 nM. Importantly, TNT can be wellndistinguished from its analogues due to their electron deficiency difference. The developed method is successfully applied to TNTnsensing in real environmental samples.