title: Study of the effect of pH, salinity and DOC on fluorescence of synthetic mixtures of freshwater and marine salts.
abstract: In order to provide support for the discussion of the fate of organic matter in estuaries, a laboratory simulation was performed by changing freshwater ionic strength, pH and organic matter content. The change in spectroscopic characteristics caused by variations in salinity, pH and organic matter concentration in the filtered samples was observed by UV-Vis and fluorescence spectroscopy. The increase in emission fluorescence intensity of dissolved organic matter (DOM) due to increasing salinity (in the range 0 to 5 g l-1) is affected by the pH of the samples. The emission fluorescence intensity at the three maxima observed in the fluorescence spectra, is linearly correlated with dissolved organic carbon (DOC) concentration at several salinity values in the same sample. The increase in organic matter concentration caused a shift in the emission peak wavelength at 410 nm for several salinity values. We concluded that it is necessary to take into account the influence of salinity and pH on emission fluorescence of dissolved organic matter if it is to be used as a tracer in estuarine or near shore areas.
authors.affiliation: University of Aveiro, Department of Chemistry, 3810 Aveiro, Portugal.
authors.forename: V I
authors.initials: VI
authors.lastname: Esteves
authors.forename: E B
authors.initials: EB
authors.lastname: Santos
authors.forename: A C
authors.initials: AC
authors.lastname: Duarte
mesh_terms: D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D009930:Organic Chemicals; D015203:Reproducibility of Results; D012965:Sodium Chloride; D013048:Specimen Handling; D013057:Spectrum Analysis; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D012965:Sodium Chloride