Relaxometry: Two-Dimensional Methods

Hills, B.P.

doi:10.1002/9780470034590.emrstm1042

Cited by 11 publications

(3 citation statements)

References 27 publications

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“…Thus, additional methods should be conducted in order to evaluate the real swelling state of a hydrogel in soil and to verify our assumptions. In this context, the standard one-dimensional 1 H NMR relaxometry should be extended by two-dimensional (2D) correlation maps (T 1 -T 2 , T 2 -D and T 2 -T 2 ) (Hills, 2009;Jaeger et al, 2010;Song et al, 2012) and thermo-analytical methods such as differential scanning calorimetry (DSC) (Kucerik et al, 2012;Schaumann, 2005) as they could possibly discriminate between soil pore water and water in hydrogels due to differences in the rotational mobility and freezing behaviour of water molecules in different environments.…”

Section: Discussionmentioning

confidence: 99%

Intrinsic and model polymer hydrogel-induced soil structural stability of a silty sand soil as affected by soil moisture dynamics

Buchmann

Bentz

Schaumann

2015

Soil and Tillage Research

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Section: Discussionmentioning

confidence: 99%

Intrinsic and model polymer hydrogel-induced soil structural stability of a silty sand soil as affected by soil moisture dynamics

Buchmann

Bentz

Schaumann

2015

Soil and Tillage Research

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“…Another strategy is by multidimensional NMR relaxation. Two-dimensional (2D) T 1 T 2 1 H NMR relaxation records a matrix of correlated spin–spin ( T 2 ) and spin–lattice ( T 1 ) relaxation times for each sample that facilitates resolution of physical confinement and chemical composition influence on cellular and subcellular water populations in plant biomass . For example, 2D NMR relaxation is used to assess postharvest produce quality and shelf-stability by studying changes in cellular water distribution due to microstructural and compositional changes in the fruit or vegetable. − Two published studies with lignocellulosic biomass , identified three unique water pools in the T 1 T 2 1 H NMR relaxation spectra of softwood at varying moisture contents.…”

Section: Introductionmentioning

confidence: 99%

Two-Dimensional ¹H-Nuclear Magnetic Resonance Relaxometry for Understanding Biomass Recalcitrance

Jeoh

Karuna

Weiss

et al. 2017

ACS Sustainable Chem. Eng.

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Low-field nuclear magnetic resonance (LFNMR) relaxometry examines the influence of the local environments within porous materials on the responses of the water-associated 1H to magnetic fields, yielding information on the chemical and physical surroundings of the water. 1D NMR relaxometry has been used to examine the relationship between water constraint within lignocellulosic biomass microstructure and its enzymatic digestibility; however, the effect of physical confinement and magnetic dephasing by the local chemistry could not be decoupled. This limitation is overcome by two-dimensional T 1 T 2 1H NMR relaxometry, where simultaneously probing the spin–lattice and spin–spin relaxation times of water 1H resolves physical and chemical contributions to relaxation times of unique water environments within the sample. 2D T 1 T 2 relaxation revealed four water environments in Norway spruce assigned to lumen and cell wall water based on water mobility in the pools. Sulfur dioxide (SO2) pretreatment of the spruce eliminated the cell wall water environments, while increasing the mobility of water in the lumens. Subsequent dewatering of pretreated spruce to high dry matter content in the samples significantly decreased water mobility in the lumens without changing the local chemical composition. For the first time, the use of 2D T 1 T 2 relaxation revealed that osmotic pressure exerted by solute (glucose or bovine serum albumin (BSA)) uptake into the microstructure of lignocellulosic biomass expands the volume of the confined spaces such as the cell lumens. The uptake of BSA was associated with increased water retention and enzymatic digestibility of SO2 pretreated spruce. Overall, 2D T 1 T 2 relaxation results suggest a relationship where increasing water mobility in the biomass microstructure reduces its recalcitrance.

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“…4.5 Two-dimensional measurements to characterize the water entrapment in porous media T 1 and T 2 relaxation times are often analyzed together (McConville et al, 2002), but correlations between longitudinal and transversal relaxation time (T 1 /T 2 ratio), as well as between transversal relaxation time and diffusion coefficient (T 2 /D), can be combined in one single T 1 -T 2 or T 2 -D NMR relaxation experiment ( Fig. 5) (Hills, 2007;Haber-Pohlmeier et al, 2010;Jaeger et al, 2010;Song et al, 2012;Tang et al, 2014).…”

Section: Self Diffusion Coefficient Of Water In Soilmentioning

confidence: 99%

Biohydrogel induced soil–water interactions: how to untangle the gel effect? A review

Brax

Buchmann

Schaumann

2017

J. Plant Nutr. Soil Sci.

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Biohydrogels such as microbial exudates and root‐derived mucilage are soil‐born cross‐linked polymers, able to form porous three‐dimensional networks during water uptake. The gel effect is the variation of soil properties, such as soil hydrology and soil structural stability, resulting from biohydrogel swelling in soil. Conventionally, soil–water–hydrogel interactions are investigated by measuring soil bulk properties such as water retention curves and porosity, without further analyzing the effect of biohydrogel phases in soil on a quantitative basis. Therefore, the evaluation of advanced and novel methods for the characterization of biohydrogel phases in soil and soil–water–hydrogel interactions is necessary. This review evaluates currently available methods for their potential to analyze processes associated to the gel effect. A promising approach to investigate the spatio‐temporal distribution of biohydrogel phases in porous media is based on Nuclear Magnetic Resonance (NMR) such as 1H‐NMR relaxometry, as well as on imaging techniques such as Environmental Scanning Electron Microscopy (ESEM). Especially NMR techniques enable the identification of different water populations based on their differences in the relaxation, and thus the mobility of water molecules in biohydrogels and non‐gel water in soil pores. Rheology measures the flow behavior of biohydrogels, providing information on the structural behavior of the hydrogel network and its gelling mechanism. Soil rheology further quantifies the effect of the biohydrogel phases on the interactions between soil particles, and thus the impact on soil microstructural stability. However, rheology does not elucidate the spatio‐temporal distribution and structural state of biohydrogel phases in soil. All in all, a systematic combination of rheology, NMR and suitable imaging methods seems promising and necessary in order to elucidate the still widely unknown gel effect in soil.

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Relaxometry: Two-Dimensional Methods

Cited by 11 publications

References 27 publications

Intrinsic and model polymer hydrogel-induced soil structural stability of a silty sand soil as affected by soil moisture dynamics

Intrinsic and model polymer hydrogel-induced soil structural stability of a silty sand soil as affected by soil moisture dynamics

Two-Dimensional ¹H-Nuclear Magnetic Resonance Relaxometry for Understanding Biomass Recalcitrance

Biohydrogel induced soil–water interactions: how to untangle the gel effect? A review

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Relaxometry: Two-Dimensional Methods

Cited by 11 publications

References 27 publications

Intrinsic and model polymer hydrogel-induced soil structural stability of a silty sand soil as affected by soil moisture dynamics

Intrinsic and model polymer hydrogel-induced soil structural stability of a silty sand soil as affected by soil moisture dynamics

Two-Dimensional 1H-Nuclear Magnetic Resonance Relaxometry for Understanding Biomass Recalcitrance

Biohydrogel induced soil–water interactions: how to untangle the gel effect? A review

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Two-Dimensional ¹H-Nuclear Magnetic Resonance Relaxometry for Understanding Biomass Recalcitrance