Reducing acquisition times in multidimensional NMR with a time-optimized Fourier encoding algorithm.

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Biophysical Chemistry

Background:

• Accelerating multidimensional nuclear magnetic resonance (NMR) acquisition is crucial for high-throughput studies and analyzing unstable samples.
• Existing fast NMR methods like non-uniform sampling and Hadamard encoding address limitations of traditional fast-Fourier-transform (FFT) methods.

Purpose of the Study:

• To explore an alternative fast NMR acquisition method leveraging a priori knowledge for efficient spectral encoding.
• To develop a technique that minimizes scan times and potential artifacts in multidimensional NMR experiments.

Main Methods:

• Utilizing polychromatic pulses and customized time delays to encode the indirect domain of NMR experiments.
• Porting the indirect-domain encoding to the excitation process, avoiding artifacts common in non-uniform sampling.
• Employing a standard 2D fast-Fourier-transform (FFT) for data processing.

Main Results:

• Demonstrated efficient Fourier encoding of the indirect domain by integrating it into the excitation process.
• Achieved a minimum number of scans equal to the number of resonances in the indirect dimension.
• Successfully acquired 2D heteronuclear correlation NMR spectra for quinine and isobutyl propionic phenolic acid.

Conclusions:

• The developed method offers a fast and artifact-free approach for multidimensional NMR acquisition.
• The technique is readily automatable for complex applications like metabolomics, in-cell, and in vivo NMR.
• This strategy enhances speed and temporal stability, critical for demanding NMR applications.