| Popis: |
Excitation Emission Matrices – EEMs – are three-dimensional representations of the total emissive light in terms of intensity and diversity of emission wavelengths one sample can gather when irradiated in a fixed range of excitation wavelength, generally between 200 nm and 700 nm. Excitation Emission Matrices of Fluorescence – EEMF – is an analytical tool of choice when investigating chromophoric complex systems made of several chemical compounds, such as those of dissolved organic matter – DOM – in surface waters.The characterization of DOM via EEMF is non invasive and easily implementable in field sampling, making it more and more used. Additionally, EEMF can provide information on chemical composition of DOM, dissociate autochthonous from allochthonous organic matter production, visualize biological activities and investigate colloidal and particulate organic matter. Transept sampling approaches along watersheds enable DOM dynamics to be studied as well as biotic (macrophyte inputs, phytoplankton blooms) and abiotic processes (photoprocesses, mineralization, water fluxes). When EEMF is coupled to data processing algorithms, like PARAFAC, hidden features from the temporal and spatial variability of DOM composition in surface waters can be revealed.In order to go deeper in the study of the molecular composition of fluorophores in DOM samples, EEMF could also be coupled with orthogonal analytical tools like ultra-high resolution mass spectrometry or nuclear magnetic resonance. Such a strategy should, in the future, enable a set of chemical moieties or families responsible for DOM's cycling and reactivity to be targeted and strengthen the powerfulness of EEMF by increasing our knowledge on the fluorescent fingerprint gathered in a single EEM. |
