Soil Organic Matter in Its Native State: Unravelling the Most Complex Biomaterial on Earth

Masoom, Hussain; Courtier‐Murias, Denis; Farooq, Hashim; Soong, Ronald; Kelleher, Brian P.; Zhang, Chao; Maas, Werner E.; Fey, Michael; Kumar, Rajeev; Monette, Martine; Stronks, Henry J.; Simpson, Myrna J.; Simpson, André J.

doi:10.1021/acs.est.5b03410

Cited by 80 publications

(82 citation statements)

References 54 publications

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“…In the contact zone of this model, proteins are proposed to sorb to the surface of phyllosilicate minerals through polar interactions, including electrostatic, cation bridging or ligand exchange associations, as well as more non-polar interactions such as hydrophobic and van der Waals bonding [51,52]. In addition, Masoom et al [28] reported that protein components of soil OM were not visible when a soil was swollen in D 2 O, but could be observed using DMSO-d 6 , a solvent which disrupts hydrogen bonding and hydrophobic interactions and penetrates beneath the outermost layers of OM [29]. This suggested that proteins are buried deeper within the soil OM microstructure and may be sorbed to the mineral surface as observed in the present study.…”

Section: Sorption Of Specific Dom Components To Kaolinitementioning

confidence: 99%

“…Furthermore, components present in the outermost layers of OM sorbed to the organo-clay complexes were characterized at selected intervals using high resolution-magic angle spinning (HR-MAS) NMR. This NMR technique permits the analysis of OM components in solid, solution and gel phases of a sample using a single NMR probe, and has been used previously to study soil OM chemistry at interfaces [14,15,28,37]. We hypothesize that the quantity and composition of OM sorbed to the initial uncoated clay mineral surfaces will be controlled primarily by mineral properties such as SSA and CEC.…”

Section: Introductionmentioning

confidence: 99%

“…This suggested that high affinity aliphatic and aromatic sorption domains in soil are buried beneath a surface layer of more polar compounds such as carbohydrates and proteins. Furthermore, the analysis of organo-clay complexes and whole soils using nuclear magnetic resonance (NMR) spectroscopy showed that aromatic signals were not visible when the samples were swollen in water (D 2 O) [15,28,29]. This indicated that aromatic components such as lignin were not in contact with the NMR solvent and thus were not present at the solid-aqueous interface.…”

mentioning

confidence: 99%

“…However, aromatic signals were observed when the samples were swollen in DMSO-d 6 , a more penetrating solvent that disrupts hydrophobic and hydrogen bonding and can probe OM components beneath the aqueous interface and surface layer of OM. These previous studies provided further evidence that aromatic components are buried deeper within the soil OM microstructure and may be partially protected from degradation by more polar compounds that are present at the soil-aqueous interface [15,28,29].Kleber et al[3] proposed a conceptual model of organo-mineral interactions in which OM may be arranged into three zones on a mineral surface. The zones are differentiated based on the proximity of the OM components to the surface and the types of sorption interactions occurring between the components.…”

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confidence: 99%

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Nuclear Magnetic Resonance Analysis of Changes in Dissolved Organic Matter Composition with Successive Layering on Clay Mineral Surfaces

et al. 2018

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Dissolved organic matter (DOM) chemistry and the potential for organic matter (OM) to self-associate with other OM components are important aspects of understanding the mechanisms of DOM sorption to clay surfaces. To investigate this further, we sorbed DOM isolated from peat humic acid onto either kaolinite, montmorillonite and gibbsite via ten sequential batch equilibration sorption experiments. Dissolved organic carbon (DOC) sorption to all minerals increased consistently, suggesting that sorption occurred via mineral-OM interactions at the beginning of the experiment. After six successive DOM loadings, the concentration of DOC sorbed by kaolinite and gibbsite began to plateau, likely due to the saturation of mineral surface sorption sites. Solution-state nuclear magnetic resonance (NMR) analysis of unbound DOM showed that kaolinite and montmorillonite sorbed aliphatic, protein and lignin components initially and primarily aliphatic and aromatic constituents in later sorption experiments, whereas gibbsite sorbed mostly aliphatic compounds during all DOM loadings. Analysis of the organo-clay complexes using 1 H high resolution-magic angle spinning (HR-MAS) NMR confirmed the preferential sorption of aromatic and aliphatic components to all three minerals. Overall, these results suggest that OM-OM interactions may be important mechanisms of DOM sorption to clay mineral surfaces.Soil Syst. 2018, 2, 8 2 of 17 such as van der Waals forces and hydrogen bonding, while aromatic components were sorbed to a lesser extent and primarily by montmorillonite [14][15][16]. Although previous studies have provided molecular-level insight into sorption processes, most have only examined one DOM loading onto the mineral surface [8][9][10][12][13][14][15][16]. In soil, a mineral particle may be coated with several layers of OM to form organo-clay complexes [3,16,17], and the mineral sorption capacity for OM may decrease with successive OM loading as reactive surface functional groups become saturated with OM [18]. Currently, it is unclear whether mineral properties such as SSA and CEC continue to control DOM sorption with increasing OM layering [19][20][21][22], which may limit the amount of OM that can be sequestered by organo-mineral associations [23].Several studies have demonstrated that OM-OM interactions may also stabilize and protect OM from degradation in soil [24][25][26]. For example, protein encapsulation in humic acid prevented hydrolysis of a proteins by strong acid [26], while coating lignin with dodecanoic acid protected the lignin from chemical degradation by NaClO 2 [24]. Similarly, Thevenot et al. [25] observed that lignin and aliphatic soil OM components such as plant and microbial lipids were associated in ligno-aliphatic complexes, which may slow lignin degradation in soil. In another study, the removal of O-alkyl soil OM components by acid hydrolysis increased the sorption capacity of several soils for three organic contaminants [27]. This suggested that high affinity aliphatic and aromatic sorption domains in ...

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Section: Sorption Of Specific Dom Components To Kaolinitementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Nuclear Magnetic Resonance Analysis of Changes in Dissolved Organic Matter Composition with Successive Layering on Clay Mineral Surfaces

et al. 2018

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“…In many ways, CMP NMR can be thought of as changing NMR technology to match natural samples, rather than changing the sample to match a specific NMR technique. CMP NMR has permitted the study of structural interactions and processes in unaltered heterogeneous samples, including soil, swelling of rubber by biofuels, intact plants, and to follow biological processes (seed growth) …”

Section: Introductionmentioning

confidence: 99%

In vivo comprehensive multiphase NMR

Mobarhan

Soong

Lane

et al. 2019

Magnetic Reson in Chemistry

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Traditionally, due to different hardware requirements, nuclear magnetic resonance (NMR) has developed as two separate fields: one dealing with solids, and one with solutions. Comprehensive multiphase (CMP) NMR combines all electronics and hardware (magic angle spinning [MAS], gradients, high power Radio Frequency (RF) handling, lock, susceptibility matching) into a universal probe that permits a comprehensive study of all phases (i.e., liquid, gel‐like, semisolid, and solid), in intact samples. When applied in vivo, it provides unique insight into the wide array of bonds in a living system from the most mobile liquids (blood, fluids) through gels (muscle, tissues) to the most rigid (exoskeleton, shell). In this tutorial, the practical aspects of in vivo CMP NMR are discussed including: handling the organisms, rotor preparation, sample spinning, water suppression, editing experiments, and finishes with a brief look at the potential of other heteronuclei (2H, 15N, 19F, 31P) for in vivo research. The tutorial is aimed as a general resource for researchers interested in developing and applying MAS‐based approaches to living organisms. Although the focus here is CMP NMR, many of the approaches can be adapted (or directly applied) using conventional high‐resolution magic angle spinning, and in some cases, even standard solid‐state NMR probes.

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SASSY NMR: Simultaneous Solid and Solution Spectroscopy

et al. 2023

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Synergism between different phases gives rise to chemical, biological or environmental reactivity, thus it is increasingly important to study samples intact. Here, SASSY (SimultAneous Solid and Solution spec-troscopY) is introduced to simultaneously observe (and differentiate) all phases in multiphase samples using standard, solid-state NMR equipment. When monitoring processes, the traditional approach of studying solids and liquids sequentially, can lead to information in the non-observed phase being missed. SASSY solves this by observing the full range of materials, from crystalline solids, through gels, to pure liquids, at full sensitivity in every scan. Results are identical to running separate 13 C CP-MAS solid-state and 13 C solution-state experiments back-to-back but requires only a fraction of the spectrometer time. After its introduction, SASSY is applied to process monitoring and finally to detect all phases in a living freshwater shrimp. SASSY is simple to implement and thus should find application across all areas of research.

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Soil Organic Matter in Its Native State: Unravelling the Most Complex Biomaterial on Earth

Cited by 80 publications

References 54 publications

Nuclear Magnetic Resonance Analysis of Changes in Dissolved Organic Matter Composition with Successive Layering on Clay Mineral Surfaces

Nuclear Magnetic Resonance Analysis of Changes in Dissolved Organic Matter Composition with Successive Layering on Clay Mineral Surfaces

In vivo comprehensive multiphase NMR

SASSY NMR: Simultaneous Solid and Solution Spectroscopy

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