Cucurbit[6]uril nanocavity as an enhanced spectrofluorimetric method for the determination of pyrene

Abstract

The effect of the addition of macrocyclic host cucurbit[6]uril (CB6) on the photophysical properties of polycyclic aromatic hydrocarbon pyrene (PYR) was analyzed. The fluorescence emission spectra of the aromatic compound were determined at 25.0°C in different acidic media (HCl 18%, w/v, or HCOOH 55%, w/v) with and without CB6. A significant enhancement in the fluorescence signals in the presence of CB6 was observed. The average values of the association constant (KA) for the 1:1 stoichiometry complex and the relative fluorescence quantum yield ratio between the complexed and free PYR (φPYR-CB6/φPYR) in acidic media were (4.0±0.5)×102M-1 and (5.7±0.2), respectively.The analytical parameters improved in the presence of CB6. The relative decrease in the limit of detection was 92%. The matrix effect was evaluated in fortified samples of tap water and tea extracts. Apparent recoveries obtained by the proposed method in tap water and tea extracts were (82-103)% and (89-99)%, respectively. Selectivity studies with inorganic and organic species were performed. The method is rapid, direct, selective and simple. © 2011 Elsevier B.V.