A new fluorescent sensor based on single water-soluble β-cyclodextrin (β-CD) molecule as the support carrier of donor and acceptor complex was designed, and used for TNT detection by fluorescence resonance energy transfer (FRET). In this sensing platform, per-6-amino-β-CD (per-6-NH 2-β-CD) was used as the detection vehicle. The probe dye of fluorescein 5(6)-isothiocyanate (FITC) was covalently linked onto the per-6-NH2-β-CD rim with the grafting molar ratio of 1:1, the residual amino groups of per-6-NH2-β-CD can adsorb TNT molecules by forming Meisenheimer complex (TNT-amine complex) with TNT. The absorbtion spectrum of this complex has a spectral overlapping with the emission of FITC in aqueous solution, so it can strongly suppress the fluorescence emission of the adjacent FITC through FRET on β-CD vehicle. This FRET-based fluorescent sensing technique provides a facile, ultrasensitive and selective detection method for TNT molecule. The observed linear fluorescence intensity change could allow the quantitative detection TNT with the detection limit of 20 nM in water.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics