Novel methodology for the analysis of high-molecular weight polycyclic aromatic hydrocarbons in water and particulate matter samples based on Shpol'skii spectroscopy

Abstract

Polycyclic aromatic hydrocarbons (PAH) are important environmental pollutants originating from a wide variety of natural and anthropogenic sources. PAH are generally formed during incomplete combustion of organic matter containing carbon and hydrogen. Because combustion of organic materials is involved in countless natural processes or human activities, PAH are omnipresent and abundant pollutants in air, soil, and water. Chemical analysis of PAH is of great environmental and toxicological importance. Recent toxicological studies attribute a significant portion of the biological activity of PAH contaminated samples to the presence of high molecular weight (HMW) PAH, i.e. PAH with MW e 300. The first group of HMW PAH, i.e. the MW 300 and MW 302 isomers, has been identified in combustion related samples with high PAH content such as coal tar, carbon black, and fuel combustion exhaust. Their presence has also been confirmed in environmental samples such as air particulate matter, mussels, sediments and soils. Coronene is generally the only MW 300 isomer measured, even though a number of other isomers are possible. However, only a limited number of studies have reported the quantification of individual isomers. The main goal of this project is to develop methods and instrumentation with the ability to efficiently and reliably detect the presence and determine the amounts of the most toxic HMW PAH in water and particulate matter samples. The proposed methodology is based on line-narrowing spectroscopy, an important area of research within the field of analytical chemistry currently lacking in Brazil. We will focus our attention on 23 isomers of MW 302, which include the most toxic/carcinogenic chemicals known to men. This new line of research will be implemented at the Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo (USP). The project will be carried out in close collaboration with Dr. Campliglia's group from the Department of Chemistry, University of Central Florida, USA. Dr. Campiglia has established himself as one of the leading experts in the area of line narrowing spectroscopy. Although room-temperature fluorescence spectroscopy techniques are widely applied in Brazil, line-narrowing spectroscopy techniques - such as Shpol'skii spectroscopy - are far from popular. Their lack of popularity is probably due to the need of cumbersome and expensive instrumentation. Our proposition will remove this limitation by developing low-temperature methodology for commercial instrumentation. The new developments will allow analysts with access to commercial spectrofluorimeters to take advantage of line-narrowing spectroscopy techniques. Line narrowing spectroscopy is a powerful approach to solve spectral interference for the direct analysis (no chromatographic separation) of fluorophors in complex samples. (AU)