Selective synchronous spectrofluorimetric detection of acenaphthene in mixtures of three-ring aromatic compounds based on complexation with cyclomaltoheptaose (β-cyclodextrin) in the presence of iodide ion as quencher

Abstract

Acenaphthene in a three-ring aromatic compound mixture can be selectively detected in a dimethyl sulfoxide–water (1 + 4) medium containing both cyclomaltoheptaose (β-cyclodextrin, β-CDx) and potassium iodide by synchronous fluorescence spectrometry. In this medium, synchronous fluorescence of acenaphthene was hardly quenched by iodide ion because of the inclusion complexation with β-CDx. According to K_sv values calculated from the simple Stern–Volmer plots, the fluorescence sensitivity to acenaphthene in the iodide-quenching state increased 364-fold in the presence of β-CDx, whereas those to other three-ring aromatics increased only 2–3-fold. Acenaphthene could be characterized by the double peaks at 322 and 328 nm in the synchronous fluorescence spectrum measured with Δλ= 7 nm. The method was applied directly to the selective detection of acenaphthene in mixtures of typical three-ring compounds, including dibenzofuran, fluorene, dibenzothiophene, carbazole, phenanthrene and anthracene, and in commercially available dibenzofuran.