Date of Award

Spring 5-19-2018

Degree Type

Dissertation

Degree Name

PhD. Chemistry

Department

Chemistry and Biochemistry

Advisor

Wyatt R. Murphy Jr., Ph.D.

Committee Member

Nicholas H. Snow, Ph.D.

Committee Member

Gerald J. Buonopane, Ph.D.

Committee Member

Cecilia H. Marzabadi, Ph.D.

Keywords

EEMs, microwell plates, automated biomonitoring, fluorescence, PAHs, PAH metabolites

Abstract

Polyaromatic hydrocarbons (PAHs) in the environment are a significant concern as many compounds in this class are potential carcinogens. PAHs resulting from petroleum spills can contaminate natural waters and the products obtain from them (fish and fish products in particular). Previous studies by Pena, et. al. on ethanolic extracts of organs from menhaden captured in the vicinity of the Deepwater Horizon (Macondo oil well) spill have shown that fluorescence excitation spectroscopy is a useful technique for detecting the presence of PAH metabolites and fluorescent vitamins. The study has also concluded that previous methods for analyzing PAHs using fluorescence spectroscopy used less than desirable fluorescence wavelengths. Continuous biomonitoring of this spill is essential. Due to the high volume of samples needed to assess accurate biomonitored data, a new technique using microwell sample holders was developed (purchased through Horiba Scientific). In order to address optimal fluorescence wavelength monitoring, the study used EEMS (excitation emission spectroscopy) as a tool for accurate and reliable data of all PAHs determined.

Currently, there is no evidence in the literature that high quality fluorescence spectral measurements (e.g. EEMS) have been attempted in microwells. Several concerns arise in these measurements. First, fluorescence measurements are normally made on samples in 1 cm quartz or fused silica cuvettes. Two optical configurations, right angle and front face, are used. Front face detection (small angle detection) is normally used for highly absorbing, scattering or turbid samples. Microwells present an optically similar arrangement to front face detection. Second, the quantum yields for fluorescence (photons emitted/photons absorbed) vary strongly among the PAHs of interest.

Comparison of standard fluorescence cuvettes to the Horiba MicroMax microwell Plate reader was conducted using twelve PAHs or their metabolites.

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