Environmental NMR: Diffusion Ordered Spectroscopy Methods

Zheng, Gang; Price, William S.

doi:10.1002/9780470034590.emrstm1336

Cited by 5 publications

(8 citation statements)

References 76 publications

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“…The DOSY parameters for model compounds were: 4.5 ms diffusion gradient length (δ), (1). 28 With the introduction of DOSY, D from the second domain may help with signal assignment.…”

Section: Nmr Parametersmentioning

confidence: 99%

“…27 In contrast, diffusion-ordered spectroscopy (DOSY) gives a 2D plot with frequency (F) in horizontal domain, and diffusion coefficient (D) in another, which directly correlates with molecular weight (MW) under certain environment. 28 In this regard, DOSY enables to virtually separate the NMR signals of different species in a second domain according to their difference in D.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, the interpretation of the corresponding 2D Spectra is also not straightforward, because there is as yet no direct separation of 31 P compounds of different size and mobility . In contrast, diffusion-ordered spectroscopy (DOSY) gives a 2D plot with frequency (F) in horizontal domain, and diffusion coefficient (D) in another, which directly correlates with molecular weight (MW) under certain environment . In this regard, DOSY enables to virtually separate the NMR signals of different species in a second domain according to their difference in D. Combining the additional information from the D domain with the chemical shifts in the F domain, confident peak identification can be achieved.…”

Section: Introductionmentioning

confidence: 99%

“…In this regard, DOSY enables to virtually separate the NMR signals of different species in a second domain according to their difference in D. Combining the additional information from the D domain with the chemical shifts in the F domain, confident peak identification can be achieved. To the best of our knowledge, DOSY is starting to gain popularity in the field of environmental research. , In fact, 1 H or 19 F DOSY has already been employed to reveal aggregation behavior of natural organic matter, , and the interaction between pollutant and humic matter in nature, , thus offering also potentials for soil P research such as their distribution in different molecular weight fractions , and the structural elucidation. The objectives of the study were (i) to demonstrate the feasibility of DOSY experiment under ideal circumstances, that is, using high concentrations of P model compounds in typical solvent (NaOD and D 2 O) but without interference such as paramagnetic ions and the viscous soil solution matrix, (ii) to revise the Na 2 S precipitation protocol for efficient and practical removal of paramagnetic ions needed for DOSY application, and (iii) to apply DOSY for soil P analysis and demonstrate its strengths and limitations.…”

Section: Introductionmentioning

confidence: 99%

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Diffusion-Ordered Nuclear Magnetic Resonance Spectroscopy (DOSY-NMR): A Novel Tool for Identification of Phosphorus Compounds in Soil Extracts

Wang¹,

Amelung

Willbold³

2017

Environ. Sci. Technol.

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Liquid-state, one-dimension P nuclear magnetic resonance spectroscopy (NMR) has greatly advanced our understanding of the composition of organic phosphorus in the environment. However, the correct assignment of signals is complicated by overlapping and shifting signals in different types of soils. We applied therefore for the first time diffusion-ordered spectroscopy (DOSY) to soil extracts, allowing us to separate phosphorus components in the second domain based on their translational diffusion coefficients. After successful application to a mixture of 14 model compounds, diffusion rates correlated closely with the molecular weight of the individual compound in aqueous solution (R = 0.97). The method was then applied to NaOH/EDTA extracts of a grassland soil, of which paramagnetic contaminations were removed with sodium sulfide following high-velocity centrifugation (21 500g, 45 min) at 4 °C. Diffusion rates in soil extracts were again closely related to molecular weight (R = 0.98), varying from 163.9 to 923.8 Da. However, our DOSY application failed for a forest soil with low organic phosphorus content. Overall, DOSY did help to clearly identify specific NMR signals like myo- and scyllo-inositol hexakisphosphate. It thus provides a more confident signal assignment than 1D P NMR, although currently the ubiquitous use of this novel methodology is still limited to soils with high organic phosphorus content.

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“…The DOSY parameters for model compounds were: 4.5 ms diffusion gradient length (δ), (1). 28 With the introduction of DOSY, D from the second domain may help with signal assignment.…”

Section: Nmr Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Diffusion-Ordered Nuclear Magnetic Resonance Spectroscopy (DOSY-NMR): A Novel Tool for Identification of Phosphorus Compounds in Soil Extracts

Wang¹,

Amelung

Willbold³

2017

Environ. Sci. Technol.

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“…For example, recent advances in Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) have provided precise elemental compositions and molecular masses of individual components of some types of DOM . The elemental ratios obtained from high-resolution FTICR-MS can be plotted in a van Krevelen-type diagram to classify the types of organic compounds that are present. − Multidimensional NMR and other techniques have shown that peptides, carbohydrates, lipids, and lignin are among the classes of compounds that are commonly found in DOM of different origins. − Particle sizes, diffusion coefficients, and fractal dimensions are other examples of DOM bulk properties that have been characterized experimentally. − …”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulation of the Structures, Dynamics, and Aggregation of Dissolved Organic Matter

Devarajan

Liang

et al. 2020

Environ. Sci. Technol.

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Dissolved organic matter (DOM) plays a significant role in the transport and transformation of pollutants in the aquatic environment. However, the experimental characterization of DOM has been limited mainly to bulk properties, and the molecular-level interactions among various components of DOM remain to be fully characterized. Here, we use molecular dynamics (MD) simulations to probe the structural properties of model DOM systems at atomic detail. The 200 ns simulations, validated by available experimental data, reveal processes and mechanisms by which chemical species (cations, peptides, lipids, lignin, carbohydrates, and some low-molecular-weight aliphatic and aromatic compounds) aggregate to form complex DOM. The DOM aggregates are dynamic, consisting of a hydrophobic core and amphiphilic exterior. The lipid tails and other hydrophobic fragments form the core, with hydrophilic and amphiphilic groups exposed to water, making DOM accessible to both polar and nonpolar species. Thus, the lipid component acts as a nucleator, whereas cations (especially Ca2+) connect the molecular fragments on the surface by coordinating with the O-containing functional groups of DOM. The structural details revealed here provide new insights including surface accessible atoms, overall assemblage, and interactions among the molecules of DOM for understanding the kinetics and mechanisms through which DOM interacts with metal and other contaminants.

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