Scalable Dissolution-Dynamic Nuclear Polarization with Rapid Transfer of a Polarized Solid

TL;DR

This paper introduces a rapid, scalable method for transferring hyperpolarized solids in dissolution-dynamic nuclear polarization, significantly reducing transfer time and maintaining high polarization levels for enhanced magnetic resonance signals.

Contribution

A novel bullet-based transfer technique enabling fast, adiabatic transfer of hyperpolarized solids with minimal relaxation, suitable for high-resolution NMR applications.

Findings

Transfer time of approximately 70 ms

Polarization levels of about 30% for 13C-labeled pyruvic acid

Method is scalable for small-volume high-resolution NMR

Abstract

In dissolution-dynamic nuclear polarization, nuclear spins are hyperpolarized at cryogenic temperatures using radicals and microwave irradiation. The hyperpolarized solid is dissolved with hot solvent and the solution is transferred to a secondary magnet where strongly enhanced magnetic resonance signals are observed. Here we present a method for transferring the hyperpolarized solid. A bullet containing the frozen, hyperpolarized sample is ejected using pressurized helium gas, and shot into a receiving structure in the secondary magnet, where the bullet is retained and the polarized solid is dissolved rapidly. The transfer takes approximately 70 ms. A solenoid, wound along the entire transfer path ensures adiabatic transfer and limits radical-induced low-field relaxation. The method is fast and scalable towards small volumes suitable for high-resolution nuclear magnetic resonance spectroscopy while maintaining high concentrations of the target molecule. Polarization levels of approximately 30% have been observed for 1-$^{\sf 13}$C-labelled pyruvic acid in solution.