Time-resolved fluorescence spectroscopy for application to PAR contaminated areas and hydrogeological research

A mobile fiber-optical sensor system for the on-line and in situ detection of aquatic fluorophores has been developed. By the use of timeresolved laser4nduced fluorescence spectroscopy the determination of cont.axni-ziants i.e. polycyclic aromatic hydrocarbons (PAH) or fluorescence tracers in various environments is possible. In both cases attempts to detect these substances in water by means of fluorescence spectroscopy are complicated by the low concentrations and the overlapping and featureless fluorescence spectra in combination with background fluorescence caused by further compounds e.g. humic material. By collecting the fluorescence decay time as an additional independent dimension, the analytical information is significantly increased, and to a certain extent the detennination of the desired analyte in complex natural mathces is possible. At a first application, the detection of pyrene (PYR) in real samples from a contaminated former coking plant site has been realized. The system is also best suitable for hydrogeological research. Here applications spread from the investigation of the fluorescence tracer migration in an artificial aquifer system to the determination of hydro.. geological parameters at a domestic waste disposal. 1 iNTRODUCTION The detection of aquatic fluorophores in complex, natural matrices is a well known problem i