T1-T2* relaxation correlation measurements

Enjilela, Razieh; Guo, Jiangfeng; MacMillan, Bryce; Marica, Florea; Afrough, Armin; Balcom, Bruce J.

doi:10.1016/j.jmr.2021.106961

Cited by 24 publications

(9 citation statements)

References 31 publications

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“…Ground mode, n = 0, T 1,0 = 0.0626 s An inversion-recovery T 1 encoding is employed in this work, but saturation-recovery T 1 encoding [40,41], and 034040-5 even more complex encoding schemes [38], are also common and possible. Important parameters in the T 1 − T 2 pulse sequence are described in the following.…”

Section: Methods and Parametersmentioning

confidence: 99%

Pore-Size Measurement from Eigenvalues of Magnetic Resonance Relaxation

et al. 2021

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Nonground eigenvalues are widely disregarded in magnetic resonance relaxation measurements of porous media due to difficulties involved in their measurement, detection, and the derivation of physically meaningful parameters from them. Such nonground eigenvalues may be experimentally observed in relaxation measurements, such as the relaxation correlation of T 1 − T 2 , and yield information on the pore size and surface relaxivity of porous media without calibration through other independent measurements. Nonground eigenvalue analysis of T 1 − T 2 measurements on Berea sandstone undertaken at three static magnetic fields produces pore sizes consistent with those obtained through x-ray microtomography and SEM measurements. Similar agreement is found for a Bentheimer sandstone with a more complex pore geometry. A phase-encoding imaging variant of this method measures the imbibition confinementsize profile in Berea sandstone. It is suggested that the existence of nonground eigenmodes may be much more prevalent in simple magnetic resonance relaxation measurements than previously considered. Therefore, it is possible to measure pore size by matching numerical Brownstein-Tarr solutions with those of experiments in a wide variety of samples and magnetic resonance methods.

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Section: Methods and Parametersmentioning

confidence: 99%

Pore-Size Measurement from Eigenvalues of Magnetic Resonance Relaxation

et al. 2021

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“…49,50 Previous work also demonstrated the resolution improvement capabilities of using T 1 -T 2 correlations to obtain higher-dimensional relaxation spectra. 42,44,51,52 This study describes the potential of using improved regularized methods for resolving overlapping SSNMR powder patterns. To this end, protocols were developed to acquire R 1 (T 1 À1 )-and R 2 (T 2 À1 )-encoded NMR datasets using WCPMG-IR, BRAIN-CP-IR, and QCPMG-IR pulse sequences.…”

Section: Introductionmentioning

confidence: 99%

“…49,50 Previous work also demonstrated the resolution improvement capabilities of using T 1 – T 2 correlations to obtain higher-dimensional relaxation spectra. 42,44,51,52…”

Section: Introductionmentioning

confidence: 99%

3D relaxation-assisted separation of wideline solid-state NMR patterns for achieving site resolution

Altenhof

Jaroszewicz

Frydman

et al. 2022

Phys. Chem. Chem. Phys.

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“…A new measurement utilizing T1-T2* relaxation-time correlation maps reported by Enjilela et al 51 has great merit for solid samples. T2* relaxation is driven by T2 relaxation which is typically very short in solid samples.…”

Section: Introductionmentioning

confidence: 99%

Relaxation Time Correlation NMR for Mechanochemical in-situ Reaction Monitoring of Metal-Organic Frameworks

Leger

Guo

MacMillan

et al. 2021

Preprint

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We present a new methodology for real-time observation of mechanochemical transformations, based on a magnetic resonance method in which T1-T2* relaxation time correlation maps are used to track the formation of the popular metal-organic framework (MOF) materials Zn-MOF-74 and ZIF-8. This two-dimensional (2D) relaxation correlation measurement is a new method utilizing simple saturation recovery to obtain a T1-T2* spectrum representing different hydrogen environments. The 2D T1-T2* results show a change in signal amplitudes, and their coordinates, within the plots as the reaction progresses, confirming reaction completion. Static solid samples are usually considered difficult to measure because of their short-lived T2* signal and their common non-exponential decay. Using a new processing method, the signal from samples with non-exponential decay was quantified. The importance of key parameters such as the instrument deadtime, the recovery times, and magnetic field strength for the measurement of solids with a short-lived signal is established. This novel magnetic resonance measurement is important since it provides a simple and easy way to analyse an entire solid reaction mixture within its reaction vessel.

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T1-T2* relaxation correlation measurements

Cited by 24 publications

References 31 publications

Pore-Size Measurement from Eigenvalues of Magnetic Resonance Relaxation

Pore-Size Measurement from Eigenvalues of Magnetic Resonance Relaxation

3D relaxation-assisted separation of wideline solid-state NMR patterns for achieving site resolution

Relaxation Time Correlation NMR for Mechanochemical in-situ Reaction Monitoring of Metal-Organic Frameworks

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