Using Fluorescence Spectrum to Differentiate Natural and Man-Made Organic Compounds in Water Environment

The fluorescence spectrum has long been used in various investigations on natural organic matters (NOM) or dissolved organic matters (DOM) freshwater, coastal and marine waters as well as wastewaters and groundwater. By comparing the synchronous excitation and emission (EX-EM) fluorescence spectrum (FS), this study develops a method to distinguish some natural and man-made pollutants, including antibiotics and humic acids, from some surface water, groundwater, and wastewaters. The locations and finger prints of fluorescence spectra indicated either special function groups and the existence of chemicals of humic acids and antibiotics. A developed computer routine permitted the operation of digitization and background adjustment of spectrum to enable the species and concentrations determination. The identification for species correction could achieve 95 per cent in multi-component analysis. With minimum or no preparation of water samples, the detection limits for different chemicals varied from several ppm to 30 ppb with relatively good correlation in single or multi-component analysis (correction from 0.55 to 0.99). Although there are some problems on accurate determination of concentrations of target chemicals, this study develop a qualitative identification method of humic acids and antibiotics in water samples from fluorescence spectrum and further extended peak positioning and statistical analysis to graphic identification. Future studies should focus on identifying function groups of chemicals and quantifying concentrations in order to rapid and accurately detect the pollutants and their fates in the environment.