Research progress on tracing and characterization of dissolved organic matter in water environment

Dissolved organic matter (DOM) in water has a wide range of sources and complex components, which can participate in the migration and transformation of heavy metals and biogeochemical cycles in water. Some technical means can be used to identify the source of DOM in water, and realize the characterization of DOM components and properties, so as to understand its ecological environmental effects. The composition, characteristics and current research hotspots of DOM in water environment were briefly introduced. The application characteristics, important characterization parameters, influencing factors and limitations of UV-Vis absorption spectroscopy, three-dimensional fluorescence spectroscopy, stable isotopes, biomarkers and FT-ICR-MS in the tracing and characterization of DOM in water environment were summarized and compared. The results showed that both UV-Vis absorption spectroscopy and three-dimensional fluorescence spectroscopy had the advantages of convenient operation, fast analysis speed and no sample destruction, but their emphasis on DOM characterization was different. Stable isotope technology focused on the isotopic composition and content of carbon, nitrogen and other elements in DOM, biomarkers could record the information of DOM molecular structure, while FT-ICR-MS could characterize DOM from the molecular level. All the above technologies have broad application prospects for DOM research. However, due to the complexity of DOM components and elements as well as the limitations of each technology, the combined use of multiple technologies has become the development trend of DOM characterization and analysis. Therefore, the conditions, objectives and advantages of multi-technology co-application were described, and the research progress and cases of water environment DOM based on multi-technology integration were summarized. Finally, the future development direction of DOM traceability and representation was prospected.