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Updated: Dec 23, 2025
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Hyperpolarized 13C Metabolic Magnetic Resonance Spectroscopy and Imaging
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Crossover from a Solid Effect to Thermal Mixing 1H Dynamic Nuclear Polarization with Trityl-OX063
Asif Equbal1, Yuanxin Li1, Tarnuma Tabassum1
1Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States.
The Journal of Physical Chemistry Letters
|April 22, 2020
Summary
Dynamic nuclear polarization (DNP) using Trityl-OX063 unexpectedly shifted from solid effect to thermal mixing for 1H NMR. This TM-DNP mechanism shows promise for enhanced NMR spectroscopy.
Area of Science:
- Magnetic Resonance Spectroscopy
- Chemical Physics
- Biophysical Chemistry
Background:
- Trityl-OX063 is a water-soluble polarizing agent used for 13C Dynamic Nuclear Polarization (DNP) NMR.
- The solid effect (SE) mechanism is typically ineffective for 1H nuclear spin polarization.
Purpose of the Study:
- To investigate the DNP mechanism for 1H nuclear spins using Trityl-OX063 at 7 Tesla.
- To identify experimental signatures of the thermal mixing (TM) DNP mechanism.
Main Methods:
- Dynamic Nuclear Polarization (DNP) NMR spectroscopy at 7 Tesla.
- Electron Paramagnetic Resonance (EPR) spectroscopy.
- Electron Double-Resonance (EDR) spectroscopy.
Main Results:
- Observed a crossover from SE to TM-DNP for 1H spins with increasing Trityl-OX063 concentration.
- Experimentally confirmed predicted TM-DNP signatures: asymmetric EPR broadening due to electron-electron couplings and hyperpolarization shown via pump-probe EDR.
- Demonstrated low microwave power requirements and high polarization transfer rates.
Conclusions:
- TM-DNP is an effective mechanism for 1H hyperpolarization using Trityl-OX063 at high magnetic fields.
- The identified experimental signatures provide robust validation for TM-DNP.
- TM-DNP offers significant advantages for NMR applications requiring enhanced sensitivity.
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