Detection of Medium-Sized Polycyclic Aromatic Hydrocarbons via Fluorescence Energy Transfer

Abstract

Reported herein is the use of proximity-induced non-covalent energy transfer for the detection of medium-sized polycyclic aromatic hydrocarbons (PAHs). This energy transfer occurs within the cavity of γ-cyclodextrin in various aqueous environments, including human plasma and coconut water. Highly efficient energy transfer was observed, and the efficiency of the energy transfer is independent of the concentration of γ-cyclodextrin used, demonstrating the importance of hydrophobic binding in facilitating such energy transfer. Low limits of detection were also observed for many of the PAHs investigated, which is promising for the development of fluorescence-based detection schemes.

Figure 1

Structures of all analytes and fluorophores targeted for investigation.

Figure 2

Schematic illustration of cyclodextrin-promoted energy transfer.

Figure 3

Energy transfer in PBS observed for (A) 4–10; (B) 6–10; and (C) 8–10. The black line represents analyte excitation and the grey line (red in online version) represents direct fluorophore excitation.

Figure 4

Energy transfer from analyte 6 to fluorophore 10 in (A) coconut water with cyclodextrin; (B) coconut water without cyclodextrin; (C) plasma with cyclodextrin; and (D) plasma without cyclodextrin. The black line represents analyte excitation and the grey line (red in online version) represents direct fluorophore excitation.