Photoluminescence Spectroscopy of Anthra-thiophenes and Benzonaphtho-thiophenes in Shpol'skii Matrixes
Maha Al-Tameemi, Sadia Arif, Andres Campiglia, Walter B. Wilson, Stephen A. Wise
The dispersion of harmful oil components into the ocean waters could pose long-term risks to flora and fauna. Due to the complexity of oil-contaminated sites, the unambiguous identification and quantitation of environmental pollutants often requires the sequence of high-performance liquid chromatography and gas chromatography-mass spectrometry. A classic example is the analysis of polycyclic aromatic hydrocarbons. This article tackles a different aspect of environmental analysis as it focuses on the Shpolskii spectroscopy of polycyclic aromatic sulfur heterocycles, specifically those belonging to the subgroups often known as anthra-thiophenes and benzonaphtho- thiophenes. Photoluminescence measurements were made with a commercial spectrofluorimeter equipped with a continuous wave excitation source for steady state measurements and a pulsed excitation source for time-resolved measurements in the phosphorescence time domain. To the extent of our literature search, this is the first report on the 4.2 K fluorescence and phosphorescence spectra of anthra-thiophenes and benzonaphtho-thiophenes, and the 77 K and 4.2 K phosphorescence lifetimes of benzonaphtho-thiophenes. 77 K and 4.2 K analytical figures of merit revealed the possibility to detect the studied compounds at the parts-per-billion (ng mL-1) concentration levels. The spectral and lifetime data gathered in this article provides the required information to choose an appropriate photoluminescence technique for the analysis of four-ring polycyclic aromatic sulfur heterocycles in complex environmental extracts.