This article provides an overview of experimental and instrumentation developed in the authors’ lab to monitor polycyclic aromatic compounds in environmental samples. We discuss significant improvements we have made to line narrowing spectroscopy measurements at liquid nitrogen (77 K) and liquid helium (4.2 K) temperatures. The main reason for seeking spectral narrowing is to differentiate the spectral features of closely related isomers with significantly different carcinogenicity and toxicity properties. The inconvenience of sample freezing procedures has been eliminated with the aid of cryogenic fiber optic probes. We present instrumentation to efficiently collect multidimensional data formats in frozen matrixes during the fluorescence and phosphorescence lifetime decays. Adding the temporal dimension to vibrationally resolved spectra provides an extremely selective tool for the determination of structural isomers in complex matrixes. Fluorescence and phosphorescence decays report on compound identification and spectral peak purity, an essential condition for the accurate quantitation of targeted isomers without previous chromatographic separation. The hyphenation of line narrowing spectroscopy to sample preparation techniques such as liquid-liquid extraction, solid- phase extraction and solid-phase nano-extraction are presented for the analysis of polycyclic aromatic hydrocarbons in water samples. These include the sixteen priority pollutants in the Environmental Protection Agency list and structural isomers with molecular weight 302.
Buy this Article