LC-QTOF-MS analyses shed new light on dissolved organic matter composition and podzolization

Dissolved Organic Matter (DOM) in soils has received much research attention over the years. This is not surprising given the important role this most mobile fraction of soil organic matter plays in processes such as pedogenesis, transport and bioavailability of natural and anthropogenic compounds, and the soil’s C cycle. With the increasing advancement of analytical chemical tools, our capabilities of studying the behaviour and interaction of DOM have developed dramatically over the years. Particularly interesting has been the development of advanced molecular characterization tools such as LC-QTOF-MS. However, while showing great promise, the interpretation and aggregation of the vast amounts of data produced by such advanced molecular approaches is a challenge

Here we show how non-target screening by LC coupled to high resolution QTOF-MS detection can be applied to obtain meaningful information about the molecular composition of DOM derived from coniferous and deciduous tree leaf litter material. We highlight both the chemical analysis and the subsequent data interpretation steps needed to arrive at identification of chemical compounds and formulas. For the latter we used a data processing workflow with the in-house developed open-source patRoon software package. As a specific example of the new possibilities opened by this type of detailed characterization methods, we present the results of its application to shed light on the role of DOM in the formation of Podzols

References                        

Brock, O., Helmus, R., Kalbitz, K., & Jansen, B. (2020). European Journal of Soil Science, 71(3), 420-432. https://doi.org/10.1111/ejss.12894

Helmus, R., Ter Laak, T., Van Wezel, A., De Voogt, P. & Schymanski, E. (2021). Journal of Cheminformatics, 13(1). https://doi.org/10.1186/s13321-020-00477-w