Quantitative Analysis of PAH-Molecules by Time-Resolved LIF-Spectroscopy in Water and in the Ground

Abstract

The increasing environmental pollution makes it necessary to develop new techniques for the trace analysis of various pollutants. For the diagnosis of oil pollution on the water surface the method of laser-induced fluorescence spectroscopy has been established during the last years [1,2,3.4]. In comparison to other spectroscopic techniques, like Raman scattering, the measurement of atomic or molecular fluorescence intensities is superior in sensitivity, because of the large cross sections [5). However, in order to improve the selectivity of this method, not only detecting fluorescence intensities at particular observation wavelengths, but also time-resolved laser-induced measurements have to be applied. Various types of oil products show significant different fluorescence decay spectra between 400 nm and 500 nm after excitation with 337.1 nm according to differing compositions of polycyclic aromatic hydrocarbon (PAH) molecules [1,2,3].