J-modulation effects in DOSY experiments and their suppression: The Oneshot45 experiment

Botana, Adolfo; Aguilar, J. A.; Nilsson, Mathias; Morris, Gareth A.

doi:10.1016/j.jmr.2010.11.012

Cited by 60 publications

(55 citation statements)

References 47 publications

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“…This distorts and weakens signals, and even increases signal overlap, 16 causing problems for chemometric work. For example, distorted signals impair the use of pattern recognition programs.…”

Section: 2mentioning

confidence: 99%

Robust NMR water signal suppression for demanding analytical applications

Aguilar

Kenwright

2016

Analyst

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Publisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. We describe the design and application of robust, general-purpose water signal suppression pulse sequences well suited to chemometric work. Such pulse sequences need to deal well with pulse mis-calibrations, radiation damping, chemical exchange, and the presence of sample inhomogeneities, as well as with significant variations in sample characteristics such as pH, ionic strength, relaxation characteristics and molecular weight. Of course, such pulse sequences should produce undistorted lineshapes and baselines and work well both under automation and in the hands of non-experts. As an example, one such pulse sequences, Robust-5, will be presented. This new pulse sequence meets those criteria and is able to reduce a 50 M proteo water signal down to a 0.9 mM level, without fine tuning, and under automation, and it is therefore well suited to the most demanding of analytical applications.

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Section: 2mentioning

confidence: 99%

Robust NMR water signal suppression for demanding analytical applications

Aguilar

Kenwright

2016

Analyst

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“…Importantly, we show that empirically optimising the choice of axis in the transverse plane can greatly reduce lineshape disturbances and signal phase errors. A modified convection-compensated pulse sequence is used to evaluate the extent of convection along each axis in a simple sample, and the Oneshot45 sequence [34,35] is used to determine the dependence of signal phase error on gradient direction and to demonstrate the improved performance possible in DOSY experiments. with Convection Compensation (DBPPSTE_CC) sequence [21], in which an imbalance delay ∆ 2 is introduced into the diffusion delay ∆ 1 to cause signal amplitude to depend on the velocity distribution within the active volume of the sample.…”

Section: Introductionmentioning

confidence: 99%

Improving accuracy in DOSY and diffusion measurements using triaxial field gradients

Király

Swan

Nilsson

et al. 2016

Journal of Magnetic Resonance

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NMR measurements of diffusion in solution, whether primarily quantitative, or, (as in DOSY, Diffusion-Ordered Spectroscopy) qualitative, can be particularly demanding. Here we show how the use of appropriate transverse (x, y) pulsed field gradients, orthogonal to the more usual z axis pulsed field gradient applied along the long axis of the sample, can greatly reduce two important sources of systematic error in diffusion experiments. These are the extra signal attenuation caused by sample convection, and gradient-dependent signal phase shifts caused by the magnetic field and field-frequency lock disturbances generated by field gradient pulses.

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“…Otherwise, problems arise which influence the accuracy of determination of selfdiffusion coefficients. [47] This is due to the fact that most of modern DOSY pulse sequences (such as Oneshot45) [48,49] employ stimulated echo (STE) elements. Its goal is to eliminate Foucault currents and effects of J-modulation.…”

Section: Resultsmentioning

confidence: 99%