Studying Organic Matter Molecular Assemblage within a Whole Organic Soil by Nuclear Magnetic Resonance

Lattao, Charisma; Birdwell, Justin E.; Wang, Jim J.; Cook, Robert L.

doi:10.2134/jeq2007.0137

Cited by 22 publications

(21 citation statements)

References 58 publications

(70 reference statements)

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“…First, the reduction of the aromatic (in the bleached sample) and carbohydrate moieties (in the hydrolyzed sample) concentrates the aliphatic and lipid-like moieties, increasing their toxicity mitigating capacity. In addition, reducing the amount of aromatic and carbohydrate moieties limits the HAs' potential to block lipid-like moieties[53, 54] from an interaction with Tx-100, enhancing their ability to interact with, and reduce the toxicity of, Tx-100.…”

Section: Discussionmentioning

confidence: 99%

Surfactant toxicity to Artemia franciscana and the influence of humic acid and chemical composition

Deese¹,

LeBlanc²,

Cook³

2016

Environ. Chem.

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Surfactants can be extremely toxic to aquatic species and are introduced to the environment in a variety of ways. It is thus important to understand how other environmental constituents, in this case humic acids (HAs), may alter the toxicity of anthropogenic surfactants. Hatching and mortality assays of Artemia Franciscana were performed for three different toxic surfactants: Triton X-100 (Tx-100, non-ionic), cetylpyridinium chloride (CPC, cationic), and sodium dodecyl sulfate (SDS, anionic). Humic acids of varying composition and concentrations were added to the assays to determine the toxicity mitigating ability of the HAs. Tx-100 had a significant toxic effect on Artemia mortality rates and HAs from terrestrial sources were able to mitigate the toxicity, but an aquatic HA did not. CPC and SDS limited hatching success of the Artemia and, as HAs were added, the hatching percentages increased for all HA sources, indicating toxicity mitigation. In order to determine which functional groups within HAs were responsible for the interaction with the surfactants, the HAs were chemically modified by: (i) bleaching to reduce aromatics, (ii) Soxhlet extraction to reduce lipids, and (iii) acid hydrolysis to reduce O- and N-alkyl groups. Although most of the modified HAs had some toxicity mitigating ability for each of the surfactants, there were two notable differences: 1) the lipid-extracted HA did not reduce the toxicity of Tx-100 and 2) the bleached HA had a lower toxicity mitigating ability for CPC than the other modified HAs.

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Section: Discussionmentioning

confidence: 99%

Surfactant toxicity to Artemia franciscana and the influence of humic acid and chemical composition

Deese¹,

LeBlanc²,

Cook³

2016

Environ. Chem.

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“…The choice of the alkyl inner tier is based on recent studies which show that predominantly alkyl moieties are sorbed to clay surfaces from humic substance solutions (SI3). , The choice of aryl moieties as the middle tier and polar hydrophilic moieties in the outer tier (Figure ) is based on the recent studies of sequential extractions and advanced NMR analyses of isolates and soils. , The platform synthesis of tier-1 ESSs (Figure ) consisted of hydrocarbon aliphatic chains of 6, 12, and 18 carbons immobilized on silica by heating with terminal trichlorosilyl derivatives of each hydrocarbon in toluene. For subsequent growth of the tier-2 oligomer blocks, an ATRP initiator was introduced on the free end of the aliphatic chain to give SiO 2 –C 11 –Br (Scheme S1).…”

Section: Resultsmentioning

confidence: 99%

Controllable and Scalable Engineered Soil Surrogates Utilizing Simulated Soil Organic Matter for the Study of Environmental, Ecological, and Agricultural Processes

Pandey

Haywood

Abdalla

et al. 2020

ACS Earth Space Chem.

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An entirely new, tunable, and scalable platform (model) approach for the detailed study of important molecular processes that take place in geomacromolecular matrices, such as soils, using block copolymer materials at inorganic interfaces has been developed and applied to gain a molecular-level understanding of environmental pollutant/soil interactions. This approach provides a scalable platform with molecular-level control of the soil organic matter (SOM) chemical composition and structure, allowing one to examine proposed SOM interactions with agricultural chemicals (ACs). Accordingly, a series of engineered soil surrogates (ESSs) utilizing simulated SOM was synthesized, in which multiblock oligomers were tethered to silica particles, creating one-, two-, and three-tiered ESSs, via controlled radical polymerization. Using norflurazon (NOR) as a model AC sorbate for batch mode sorption experiments, it was found that binding interactions with the ESSs are not just organic content-driven but are also dependent on the nature of the chemical structure of an ESS. By a stepwise increase in the polarity of the second and third tiers, it is shown that the ability of the ESS to sorb NOR decreases, pointing to a largely hydrophobic driving force for NOR adsorption to the ESSs. The ESS platform approach also allows for the investigation of other, more nuanced interactions with this study, directly showing that hydrogen bonding, electrostatic interactions, conformation, and π-stacking strongly influence NOR binding. This approach can also be applied to a range of other environmentally and agriculturally important issues, such as soil remediation, microbial community dynamics and evolution, nutrient cycling, and carbon sequestration, where soil variability between replicate samples has limited research advances.

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“…As already mentioned, LG-CP build-ups have been extensively explored to obtain information about internuclear distances and molecular motions. 15,[42][43][44] However, not much attention has been devoted to LG-CP Hartmann-Hahn (HH) matching profiles, which also depend on the dipolar coupling strength, and thus can also be used to obtain either internuclear distances or motional parameters. Before discussing the influence of dynamics on HH matching profiles, let us first examine its sensitivity to dipolar couplings.…”

Section: Results and Discussion A Lg-cp For Probing Intermediate Dyna...mentioning

confidence: 99%

Intermediate motions and dipolar couplings as studied by Lee–Goldburg cross-polarization NMR: Hartmann–Hahn matching profiles

Cobo

Maliňáková

Reichert

et al. 2009

Phys. Chem. Chem. Phys.

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In this article, we evaluate the use of simple Lee-Goldburg cross-polarization (LG-CP) NMR experiments for obtaining quantitative information of molecular motion in the intermediate regime. In particular, we introduce the measurement of Hartmann-Hahn matching profiles for the assessment of heteronuclear dipolar couplings as well as dynamics as a reliable and robust alternative to the more common analysis of build-up curves. We have carried out dynamic spin dynamics simulations in order to test the method's sensitivity to intermediate motion and address its limitations concerning possible experimental imperfections. We further demonstrate the successful use of simple theoretical concepts, most prominently Anderson-Weiss (AW) theory, to analyze the data. We further propose an alternative way to estimate activation energies of molecular motions, based upon the acquisition of only two LG-CP spectra per temperature at different temperatures. As experimental tests, molecular jumps in imidazole methyl sulfonate, trimethylsulfoxonium iodide, and bisphenol A polycarbonate were investigated with the new method.

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Studying Organic Matter Molecular Assemblage within a Whole Organic Soil by Nuclear Magnetic Resonance

Cited by 22 publications

References 58 publications

Surfactant toxicity to Artemia franciscana and the influence of humic acid and chemical composition

Surfactant toxicity to Artemia franciscana and the influence of humic acid and chemical composition

Controllable and Scalable Engineered Soil Surrogates Utilizing Simulated Soil Organic Matter for the Study of Environmental, Ecological, and Agricultural Processes

Intermediate motions and dipolar couplings as studied by Lee–Goldburg cross-polarization NMR: Hartmann–Hahn matching profiles

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