Separation of Structural Components in Soil Organic Matter by Diffusion Ordered Spectroscopy

Simpson, André J.; Kingery, William L.; Spraul, Manfred; Humpfer, Eberhard; Dvortsák, Péter; Kerssebaum, Rainer

doi:10.1021/es0106218

Cited by 71 publications

(62 citation statements)

References 21 publications

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“…Activation of bulk SRFA is interim between F3 and F4, consistent with results for estimated molecular weight, and the knowledge that SRFA is dominated by relatively small molecular weight species (Piccolo, 2001;Simpson et al, 2001;Sutton et al, 2005). The same behavior is seen at all supersaturations (see Table 5).…”

Section: Srfa Aciditysupporting

confidence: 85%

Cloud Condensation Nuclei properties of model and atmospheric HULIS

et al. 2006

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Abstract. Humic like substances (HULIS) have been identified as a major fraction of the organic component of atmospheric aerosols. These large multifunctional compounds of both primary and secondary sources are surface active and water soluble. Hence, it is expected that they could affect activation of organic aerosols into cloud droplets. We have compared the activation of aerosols containing atmospheric HULIS extracted from fresh, aged and pollution particles to activation of size fractionated fulvic acid from an aquatic source (Suwannee River Fulvic Acid), and correlated it to the estimated molecular weight and measured surface tension. A correlation was found between CCN-activation diameter of SRFA fractions and number average molecular weight of the fraction. The lower molecular weight fractions activated at lower critical diameters, which is explained by the greater number of solute species in the droplet with decreasing molecular weight. The three aerosol-extracted HULIS samples activated at lower diameters than any of the sizefractionated or bulk SRFA. The Köhler model was found to account for activation diameters, provided that accurate physico-chemical parameters are known.

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Section: Srfa Aciditysupporting

confidence: 85%

Cloud Condensation Nuclei properties of model and atmospheric HULIS

et al. 2006

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“…to provide MW information for samples being analyzed [32,[34][35][36][37][38][39]. Different forms of diffusion NMR experiments have been applied for diverse varieties of systems including inorganic materials [37,[40][41][42], organic molecules [17,23,24,28,[43][44][45][46][47][48][49] and polymers of different kinds (inorganic and organic polymers, polysaccharides, proteins) [21,37,[50][51][52][53][54][55][56][57][58][59][60][61][62]. Application for nucleic acids has been rather limited because the well-defined double helical structures have been investigated for most cases.…”

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confidence: 99%

Diffusion-ordered nuclear magnetic resonance spectroscopy for analysis of DNA secondary structural elements

Ambrus¹,

Yang²

2007

Analytical Biochemistry

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Structure determination of secondary DNA structural elements, such as G-quadruplexes, gains an increasing importance as fundamental physiological roles are being associated with the formation of such structures in vivo. A truncated native DNA sequence generally requires further optimization to obtain a candidate with desired NMR properties for structural analysis in solution. The optimum sequence is expected to form one dominant, stable molecular entity in solution with well-resolved NMR peaks. However, DNA sequences are prone to form structures composed of one, two, three or four strands depending on sequence and solution conditions. The thorough characterization of the molecularity (stoichiometry and molecular weight) and appropriate solution conditions for sequences with different modifications traditionally applies analytical techniques that generally do not represent the solution conditions for NMR structure determination. Here we present the application of diffusion ordered NMR spectroscopy as a useful analytical tool for the optimization and analysis of DNA secondary structural elements, specifically, the DNA G-quadruplex structures, including those formed in the human telomeric sequence and in the promoter regions of bcl-2 and c-myc genes. KeywordsDNA; NMR; DOSY; quadruplex; bcl-2; human telomere; c-myc Structural analysis of unusual DNA motifs with particular emphasis on G-quadruplexes and imotifs has a central role in the identification and characterization of molecular targets related to these structures [1][2][3][4][5][6][7]. Such structures are implicated in several physiologically important regulatory processes, with special emphasis on carcinogenesis [4][5][6][7][8][9][10][11][12]. Most of the structural studies on these elements have been performed by NMR spectroscopy. In most cases the related nucleotide sequence bearing the actual physiological function in vivo needs to be truncated/ elongated and/or mutated in order to obtain a successful candidate for NMR structure determination [3][4][5][6][7]13]. This NMR candidate should be a well-defined molecular entity in physiologically relevant solution conditions (ionic strength, pH, temperature) representing the same conformation as the original sequence. Appropriate modification of the sequence by mutation/truncation/elongation will force the molecule to form a single stable structure without altering crucial connectivities (conformation) of the structure.* To whom correspondence should be addressed at the Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, 1703 E. Mabel St., P.O. Box 210207, room 101/406, Tucson, Arizona 85721, USA; Tel: +1 520 626 6749/626 5969, Fax: +1 520 626 2466, E-mail: ambrus@pharmacy.arizona.edu, yangd@pharmacy.arizona.edu.Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of ...

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“…[60,98,99] DOSY-NMR is based on a pulsed field gradient sequence that enables measurement of translational diffusion (conventionally defined as self-diffusion) of dissolved molecules and provides direct information on molecular dynamics, including intermolecular interactions [100,101] and conformational changes. [102,103] Following the Einstein-Stokes theory, the diffusivity of a molecule decreases when its hydrodynamic radius increases, and information on intermolecular associations may be obtained by measuring the diffusion coefficient in a molecular system.…”

Section: Molecular Diffusionmentioning

confidence: 99%

“…[107,108] Thus, for mixtures containing NOM and a contaminant, DOSY-NMR has the potential to map the changes in diffusion of both the contaminant and the surrounding molecules, thus providing a direct evidence of the occurred interactions. [98] However, analogously to relaxation parameters, also in case of self-diffusion, one has to take into account that the self-diffusion measured by DOSY-NMR corresponds to an intermediate value between those of both the free and bound ligands.…”

Section: Molecular Diffusionmentioning

confidence: 99%

“…The technique was also efficiently applied in environmental studies and focused on interactions between NOM and organic molecules. [28,60,86,88,98] An early example was the application of DOSY-NMR to compare the extent of interactions between a peat HA and both the methyl tert-butyl ether, an important petroleum additive, and chlorsulfuron, a widely used and toxic herbicide. [47] In this work, the two contaminants were mixed with HA, and a series of 1D bipolar pulse pair longitudinal eddy-current delay diffusion experiments at increasing gradient strength was then acquired.…”

Section: Molecular Diffusionmentioning

confidence: 99%

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Interactions between natural organic matter and organic pollutants as revealed by NMR spectroscopy

Mazzei¹,

Piccolo²

2015

Magnetic Reson in Chemistry

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Natural organic matter (NOM) plays a critical role in regulating the transport and the fate of organic contaminants in the environment. NMR spectroscopy is a powerful technique for the investigation of the sorption and binding mechanisms between NOM and pollutants, as well as their mutual chemical transformations. Despite NMR relatively low sensibility but due to its wide versatility to investigating samples in the liquid, gel, and solid phases, NMR application to environmental NOM-pollutants relations enables the achievement of specific and complementary molecular information. This report is a brief outline of the potentialities of the different NMR techniques and pulse sequences to elucidate the interactions between NOM and organic pollutants, with and without their labeling with nuclei that enhance NMR sensitivity.

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Separation of Structural Components in Soil Organic Matter by Diffusion Ordered Spectroscopy

Cited by 71 publications

References 21 publications

Cloud Condensation Nuclei properties of model and atmospheric HULIS

Cloud Condensation Nuclei properties of model and atmospheric HULIS

Diffusion-ordered nuclear magnetic resonance spectroscopy for analysis of DNA secondary structural elements

Interactions between natural organic matter and organic pollutants as revealed by NMR spectroscopy

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