Abstract

Photoluminescence phenomena provide valuable information for the direct analysis of target chemicals in complex samples. To take full advantage of the information content of fluorescence and phosphorescence phenomena, the analyst should have access to instrumentation capable to record data formats in the wavelength and time domains. Previous efforts in our lab have developed laser-based instrumentation to combine spectral and lifetime information into data formats known as wavelength time matrices (WTMs) and time-resolved excitation emission matrices (TREEMs). Recording WTMs during the emission decay of the sample makes it possible to unambiguously identify chemicals on the bases of spectral and lifetime information. TREEMs add the temporal dimension to excitation-emission matrices allowing the analyst to enhance the spectral features of any given fluorophore (or phosphor) by choosing an appropriate time window during the total emission decay of the sample. Processing TREEMs with second order multivariate calibration algorithms provides an accurate solution to unpredictable spectral interference, a ubiquitous problem in samples of unknown composition. The main limitation of the previous instrumental system was the narrow range of excitation wavelengths of the tunable dye laser used for sample excitation. This dissertation removes the limitation with an optical parametric oscillator (OPO)-based wavelength tuning laser. It is possible now to excite photoluminescence compounds at their maximum excitation wavelengths within a wide range of ultraviolet and visible wavelengths. Additional improvements include the development of instrumental software for fast acquisition of WTMs and TREEMs. The new instrument was first applied to the analysis of 10 commercially available polycyclic aromatic hydrocarbons (PAHs) and one non-commercially available PAH (Dibenzo[b,l]Fluoranthene) in a standard reference material (SRM 1597a) at the parts per trillion concentration levels. To the extent of our knowledge, this is the first time that Dibenzo[b,l]Fluoranthene is unambiguously determined in a SRM from the National Institute of Standards and Technology (NIST).

Notes

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Graduation Date

2023

Semester

Spring

Advisor

Campiglia, Andres

Degree

Doctor of Philosophy (Ph.D.)

College

College of Sciences

Department

Chemistry

Degree Program

Chemistry

Identifier

CFE0009596; DP0027619

URL

https://purls.library.ucf.edu/go/DP0027619

Language

English

Release Date

May 2023

Length of Campus-only Access

None

Access Status

Doctoral Dissertation (Open Access)

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Chemistry Commons

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