Quantifying the transfer and settling in NMR experiments with sample shuttling.

Area of Science:

• Magnetic Resonance Spectroscopy
• Physical Chemistry
• Materials Science

Background:

• Nuclear Magnetic Resonance (NMR) with pulsed magnetic field gradients is effective for measuring molecular diffusion with short correlation times.
• Studying incoherent random motions over macroscopic scales with long correlation times requires advanced NMR techniques.

Purpose of the Study:

• To demonstrate a single-scan NMR technique for measuring molecular diffusion over macroscopic length scales.
• To apply this technique to study fluid settling and optimize NMR experiments combined with dissolution dynamic nuclear polarization.

Main Methods:

• Encoding magnetization helices and generating stimulated gradient echo trains after varying mixing times.
• Utilizing a single-scan NMR approach to capture molecular motions with correlation times similar to the experimental timescale.
• Analyzing NMR linewidth broadening effects caused by microbubbles and susceptibility differences.

Main Results:

• An effective dispersion coefficient for fluid settling was determined.
• The technique allowed for the optimization of timing in NMR experiments coupled with sample shuttling.
• Microbubbles were identified as a source of NMR linewidth broadening, impacting signal attenuation predictions.

Conclusions:

• The single-scan NMR diffusion measurement technique is versatile for studying slow, incoherent motions.
• The method provides insights into fluid dynamics and experimental artifact contributions in advanced NMR.
• Accurate prediction of signal attenuation in single-scan 2D correlation spectroscopy NMR experiments is achievable.