Time Resolved Excitation Emission (TEE) Spectra: A New Screening Tool Based on Multidimensional Fluorescence Spectroscopy

Abstract

Fluorescence spectroscopy is a sensitive method for the detection of anthropogenic fluorescent pollutants, e.g., oils and fuels or polycyclic aromatic hydrocarbons (PAH), in our environment. However, for applications with fibre optical sensor systems static emission spectra do not always provide sufficient information due to their broad and featureless character. In the case of complex mixtures of fluorophores and chromophores, the fluorescence emission spectra and fluorescence lifetime show a pronounced dependence from the excitation wavelength. Hence additional orthogonal dimensions such as decay time and variable excitation wavelengths are needed. The objective of this work is to utilize a combination of static and dynamic fluorescence spectroscopy, i.e., time resolved excitation emission (TEE) fluorescence spectroscopy, for a fibre optical sensor system. The obtained trilinear data arrays, i.e., fluorescence intensity vs. time, excitation, and emission wavelength, provide then a multitude of information about the excited molecules and their local environment.