Parahydrogen-Induced Polarization Relayed via Proton Exchange

Area of Science:

• Nuclear Magnetic Resonance Spectroscopy
• Hyperpolarization Techniques
• Quantum Chemistry

Background:

• Nuclear spin hyperpolarization significantly expands magnetic resonance (MR) applications in chemistry and biomedicine.
• Developing efficient and cost-effective hyperpolarization methods remains an active research area.

Purpose of the Study:

• To introduce a novel hyperpolarization method combining direct parahydrogenation with polarization transfer via proton exchange.
• To demonstrate the effectiveness of this new method for polarizing various target molecules.

Main Methods:

• Utilized the propargyl alcohol + parahydrogen (pH2) system for direct 1H hyperpolarization.
• Employed proton exchange to relay polarization from the hyperpolarized intermediate (allyl alcohol) to target molecules.
• Investigated polarization levels in water, alcohols, lactate, glucose, and pyruvic acid.

Main Results:

• Achieved 1H polarization exceeding 13% (P ≈ 13%) using 50% enriched pH2 at ~1 bar.
• Successfully relayed polarization to target molecules, with water and alcohols reaching P ≈ 1% at 100 mM.
• Demonstrated polarization of biologically relevant molecules like lactate, glucose, and pyruvic acid.

Conclusions:

• The parahydrogen-induced hyperpolarization relayed via proton exchange (PHIP-X) method offers a versatile approach for hyperpolarizing a wide range of molecules.
• This technique holds promise for advancing magnetic resonance applications in diverse scientific fields.
• Potential improvements for the methodology were discussed, suggesting future research directions.