Deciphering dissolved organic matter by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS): from bulk to fractions and individuals

Exploring the source, transformation pathways, and the fate of natural organic matter (NOM) is critical to understanding the regional/global carbon cycle and carbon budget. The dissolved fraction of NOM, i.e., dissolved organic matter (DOM), is a complex mixture resulting from the transformation of plant, animal and microbial matter and plays a crucial role in many biogeochemical processes at the land-ocean-atmosphere interfaces. The advance of Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) makes the detailed characterization of DOM at the molecular level possible. On the other hand, elucidation of complex DOM sample also presents significant analytical challenges, and these challenges also act as a driving force for the instrumentation and methodology development on FT-ICR MS. This review article has been written to aid those working in biogeochemistry, environmental and atmospheric chemistry, and related areas which investigate elemental cycles and DOM transformations. First, the fundamental theory, historical perspective, and recent advances in the field have been introduced. The detailed molecular characterization of environmental and geological samples continues to present significant analytical challenges, and it also has become a driving force for the development of the instrumentation and experimental methods. These achievements in DOM analysis have had an impact upon the fields of environmental science, geochemistry, and analytical chemistry. Next, varieties of applications of FT-ICR MS have also been described, followed by our view of the future of this technique in earth science research. We believe that this review covers the essential pairing of FT-ICR MS and collectively offers environmental and geochemical scientists a substantial resource for their research. Graphical abstract