Zero- to Ultralow-Field NMR Spectroscopy of Small Biomolecules

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Biophysics

Background:

• Nuclear magnetic resonance (NMR) spectroscopy is crucial for chemical analysis but typically requires complex, high-field infrastructure.
• Existing benchtop NMR systems are not easily assembled from commercial components, limiting accessibility.

Purpose of the Study:

• To demonstrate the construction of a portable, zero-field NMR spectrometer using commercially available parts.
• To explore the analytical chemistry applications of this portable zero-field NMR system, including J-spectroscopy and relaxometry.

Main Methods:

• Construction of a portable zero-field NMR spectrometer utilizing a commercial magnetometer.
• Acquisition of J-spectra for small biomolecules: [13C]-formic acid, [1-13C]-glycine, [2,3-13C]-fumarate, and [1-13C]-d-glucose.
• Investigation of relaxometry using a transverse magnetic field during detection.

Main Results:

• Successfully acquired J-spectra of various small biomolecules.
• Demonstrated that water relaxation time is concentration-dependent for dissolved d-glucose (1-10 mM).
• Indicated potential for indirect glucose concentration assessment in aqueous solutions.

Conclusions:

• The portable zero-field NMR spectrometer offers a viable, accessible platform for chemical analysis.
• The system shows promise for analyzing aqueous solutions of biomolecules and for non-invasive glucose monitoring.
• Highlights the potential of portable zero-field NMR sensors for applications beyond traditional research laboratories.