Fluorescence decay of natural organic matter (NOM)-influence of fractionation, oxidation, and metal ion complexation

Time-resolved fluorescence measurements of aquatic natural organic matter ( NOM) derived from different origins were performed using the time-correlate d. single-photon counting technique. The obtained experimental data were an alyzed with nonlinear least-squares (NLLS) algorithms. The results of a glo bal analysis with three exponential decay terms were compared with the resu lts obtained in a distribution analysis (exponential series method; ESM). F ulvic acid fractions from a bog lake water, from a brown coal production ef fluent, and from a soil seepage water as well as NOM from a municipal waste water were investigated. The influence of the emission wavelength on the N OM fluorescence decay was monitored. Furthermore, the influence of fraction ation using size exclusion chromatography, of ozonation, and of metal ion c omplexation on the fluorescence decay of the NOM samples was investigated.