Perspectives of High‐Resolution Mass Spectrometry in Soil Science

ABSTRACT Soil biogeochemical research requires specific, sensitive, and accurate methods to identify and quantify organic molecules in order to trace biochemical processes and assess element cycling in complex, heterogenous systems. High‐resolution mass spectrometry (HRMS) has evolved into a transformative tool for unraveling the complex chemical composition of organic matter applicable to a wide range of analytes from proteins to metabolites and xenobiotics. Next to its quantitative capability, HRMS enables analysis of elemental and isotope compositions, protein amino‐acid sequences, and other molecular structural information, including structural moieties and collisional cross sections. Coupled with gas or liquid chromatography, HRMS offers the opportunity to validate complementary methods and improve accuracy and specificity by reducing artifacts from isobaric and isomeric compounds using structural confirmation obtained by tandem MS. HRMS can also be used for direct surface analysis that does not rely on extraction protocols, thus enabling the examination of largely untreated solid soil samples and providing additional spatial context when used in imaging mode. Finally, HRMS platforms allow for multi‐target analyses, for example, by combining molecular marker classes such as sugars, phenols, terpenoids, lipids, and even multi‐omics approaches. In this perspective we (1) provide an overview of the current state of methods and applications in soil science and (2) outline how integrative HRMS analyses of gaseous, liquid, and solid samples hold the promise of pushing forward the limits of soil biogeochemical research.