The effect of instrument resolution on diffusion coefficients measured using NMR spectroscopy

10.1617/13676 ◽  
2001 ◽  
Vol 34 (241) ◽  
pp. 389-395
Author(s):  
G. H. Galbraith
2001 ◽  
Vol 34 (7) ◽  
pp. 389-395
Author(s):  
G. H. Galbraith ◽  
J. Guo ◽  
R. C. McLean ◽  
A. S. M. Y. Munsi ◽  
C. H. Sanders

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1723 ◽  
Author(s):  
Martin Pulst ◽  
Yury Golitsyn ◽  
Detlef Reichert ◽  
Jörg Kressler

1,2,3-Triazolium salts are an important class of materials with a plethora of sophisticated applications. A series of three novel 1,3-dimethyl-1,2,3-triazolium salts with fluorine, containing anions of various size, is synthesized by methylation of 1,2,3-triazole. Their ion conductivity is measured by impedance spectroscopy, and the corresponding ionicities are determined by diffusion coefficients obtained from 1H and 19F pulsed field gradient nuclear magnetic resonance (PFG NMR) spectroscopy data, revealing that the anion strongly influences their ion conductive properties. Since the molar ion conductivities and ionicities of the 1,3-dimethyl-1,2,3-triazolium salts are enhanced in comparison to other 1,2,3-triazolium salts with longer alkyl substituents, they are promising candidates for applications as electrolytes in electrochemical devices.


2003 ◽  
Vol 69 (11) ◽  
pp. 6644-6649 ◽  
Author(s):  
Piet N. L. Lens ◽  
Rakel Gastesi ◽  
Frank Vergeldt ◽  
Adriaan C. van Aelst ◽  
Antonio G. Pisabarro ◽  
...  

ABSTRACT The diffusive properties of anaerobic methanogenic and sulfidogenic aggregates present in wastewater treatment bioreactors were studied using diffusion analysis by relaxation time-separated pulsed-field gradient nuclear magnetic resonance (NMR) spectroscopy and NMR imaging. NMR spectroscopy measurements were performed at 22°C with 10 ml of granular sludge at a magnetic field strength of 0.5 T (20 MHz resonance frequency for protons). Self-diffusion coefficients of H2O in the investigated series of mesophilic aggregates were found to be 51 to 78% lower than the self-diffusion coefficient of free water. Interestingly, self-diffusion coefficients of H2O were independent of the aggregate size for the size fractions investigated. Diffusional transport occurred faster in aggregates growing under nutrient-rich conditions (e.g., the bottom of a reactor) or at high (55°C) temperatures than in aggregates cultivated in nutrient-poor conditions or at low (10°C) temperatures. Exposure of aggregates to 2.5% glutaraldehyde or heat (70 or 90°C for 30 min) modified the diffusional transport up to 20%. In contrast, deactivation of aggregates by HgCl2 did not affect the H2O self-diffusion coefficient in aggregates. Analysis of NMR images of a single aggregate shows that methanogenic aggregates possess a spin-spin relaxation time and self-diffusion coefficient distribution, which are due to both physical (porosity) and chemical (metal sulfide precipitates) factors.


2008 ◽  
Vol 86 (6) ◽  
pp. 579-585 ◽  
Author(s):  
Héloise Thérien-Aubin ◽  
Wilms E Baille ◽  
X X Zhu

Pulsed-field gradient NMR spectroscopy was used to study the interactions between small molecular probes and polymers bearing interacting groups. The self-diffusion coefficients of ethylene glycol and its oligomers and their methyl ester derivatives in poly(vinyl alcohol) gels were measured to study the effect of hydrogen bonding. The self-diffusion coefficients of small molecular probes containing hydroxyl, amine, and carboxylic acid groups were determined in several polymer matrices including poly(vinyl alcohol), poly(allylamine), and poly(acrylic acid) bearing lateral hydroxyl, amine, and carboxylic acid groups, respectively. The ionic interactions between the functional groups of the diffusants and of the polymers exhibited a marked effect on the diffusion of the molecular probes. For example, the reduced self-diffusion coefficients measured for a diffusant with a carboxylic acid group in a poly(allylamine) matrix were shown to be lower even though the molecular masses of the diffusants are similar.Key words: pulsed-field gradient NMR spectroscopy, self-diffusion, intermolecular interactions.


1996 ◽  
Vol 29 (6) ◽  
pp. 2138-2142 ◽  
Author(s):  
Jeffrey H. Simpson ◽  
Wen ◽  
Alan A. Jones ◽  
Paul T. Inglefield ◽  
John T. Bendler

2016 ◽  
Vol 40 (9) ◽  
pp. 7657-7662
Author(s):  
Mathieu Meyer ◽  
Lydie Viau ◽  
Ahmad Mehdi ◽  
Sophie Monge ◽  
Patrick Judeinstein ◽  
...  

High molecular weight polysilsesquioxane lithium salts were prepared. Ion self-diffusion coefficients and transference numbers in acetonitrile solutions were quantified by PFG NMR spectroscopy.


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